diff --git "a/raw_rss_feeds/https___arxiv_org_rss_physics.xml" "b/raw_rss_feeds/https___arxiv_org_rss_physics.xml" --- "a/raw_rss_feeds/https___arxiv_org_rss_physics.xml" +++ "b/raw_rss_feeds/https___arxiv_org_rss_physics.xml" @@ -7,2212 +7,2497 @@ http://www.rssboard.org/rss-specification en-us - Wed, 10 Dec 2025 05:00:03 +0000 + Thu, 11 Dec 2025 05:00:13 +0000 rss-help@arxiv.org - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 Saturday Sunday - Normal form computation of nonlinear dispersion relationship for locally resonant metamaterial - https://arxiv.org/abs/2512.07861 - arXiv:2512.07861v1 Announce Type: new -Abstract: This article is devoted to the application of the parametrisation method for invariant manifold with a complex normal form style (CNF), for the derivation of high-order approximations of underdamped nonlinear dispersion relationships for periodic structures, more specifically by considering the case of a locally resonant metamaterial chain incorporating damping and various nonlinear stiffnesses. Two different strategies are proposed to solve the problem. In the first one, Bloch's assumption is first applied to the equations of motion, and then the nonlinear change of coordinates provided by the complex normal form style in the parametrisation method is applied. This direct procedure, which applies first the wave dependency to the original physical coordinates of the problem, is referred to as CNF-BP (for CNF applied with Bloch's assumption on physical coordinates). In the second strategy, the nonlinear change of coordinates provided by the parametrisation method, which relates the physical coordinates to the so-called normal coordinates, is first applied. Then the periodic assumption is used, thus imposing a Bloch wave ansatz on the normal coordinates. This method will be referred to as CNF-PN (for CNF with a periodic assumption on normal coordinates). In the conservative case, the CNF-PN strategy exhibits superior capability in capturing complex wave propagation phenomena, whereas the CNF-BP strategy encounters limitations in handling non-fundamental harmonics and the nonlinear interactions between host oscillators. For underdamped systems, the CNF-PN is rigorously validated and systematically compared against numerical techniques, a classical analytical perturbation technique (the method of multiple scales), and direct numerical time integration of annular chain structures. - oai:arXiv.org:2512.07861v1 - physics.optics - math.DS - physics.app-ph + A Unified Variational Framework for Planar Elastica with General Distributed Loads + https://arxiv.org/abs/2512.08958 + arXiv:2512.08958v1 Announce Type: new +Abstract: We present a simple variational framework for planar elastica that enables distributed energies, such as gravitational loading or magnetic body torques, to be incorporated in a modular and unified manner. The formulation is based on expressing all load induced contributions directly at the level of the energy functional, which avoids the force balance constructions used in classical treatments such as Wang (1986) and makes the inclusion of additional physical effects straightforward. The resulting planar energy functional yields compact governing equations in which the contributions of individual load types remain clearly separated. We demonstrate that the framework reproduces the classical heavy elastica equations exactly and naturally accommodates magnetic energy terms commonly used in hard magnetic rod models. Although mathematically elementary, the formulation provides a clean and extensible structure for describing planar rod deformations under general distributed loads. + oai:arXiv.org:2512.08958v1 physics.class-ph - Wed, 10 Dec 2025 00:00:00 -0500 - new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Tao Wang, Cyril Touz\'e, Haiqin Li, Qian Ding - - - Referenceless Proton Resonance Frequency Thermometry Using Deep Learning with Self-Attention - https://arxiv.org/abs/2512.07882 - arXiv:2512.07882v1 Announce Type: new -Abstract: Background: Accurate proton resonance frequency (PRF) MR thermometry is essential for monitoring temperature rise during thermal ablation with high intensity focused ultrasound (FUS). Conventional referenceless methods such as complex field estimation (CFE) and phase finite difference (PFD) tend to exhibit errors when susceptibility-induced phase discontinuities occur at tissue interfaces. - oai:arXiv.org:2512.07882v1 - physics.med-ph - cs.AI - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Yueran Zhao, Chang-Sheng Mei, Nathan J. McDannold, Shenyan Zong, Guofeng Shen + Yimu Mao, Christopher Tropp - Idealized Cumulus Cloud-Scale Motions and the Dynamics of Isolated and Coupled Flows - https://arxiv.org/abs/2512.07889 - arXiv:2512.07889v1 Announce Type: new -Abstract: Developing an understandable theory for the dynamic evolution of the morphology of clouds remains intractable. To break this deadlock, we introduce a new conceptual model for cloud-scale motions named the Kinematics Representation of Non-rotating Updraft Tori (KRoNUT) model, where non-rotating reflects the absence of motion in the azimuthal direction. Using this model, we conduct a series of relaxation experiments whereby we ``turn off'' the baroclinic term associated with a pre-existing cloud-scale circulation. We then implement a moment reduction technique to generate a system of differential equations named the Dynamics of Non-rotating Updraft Tori (DoNUT) equations, which describe the temporal evolution of a cloudy circulation under various combinations of forcings, namely turbulent diffusion, self-advection, and cross-advection from a neighboring cloud-scale flow. The solutions of the DoNUT equations show that all single KRoNUT configurations either start at or evolve toward a specific steady state circulation. The cloud-scale motions represented by the current KRoNUT model always grow vertically but may narrow, due to advection, or widen, due to diffusion. Meanwhile, invigoration or enervation of the vertical velocity may result from advection or diffusion processes, with short, wide KRoNUTs more likely to invigorate and tall, narrow KRoNUTs likely to enervate. Our study of the coupled KRoNUTs provides insight into clouds' tendencies to attract or repel one another. Important results of the coupled KRoNUT analysis include a scaled metric for interaction, ranges of specific height ratios that induce the most meaningful interaction, and circulation parameters that alter the location and stability of a steady KRoNUT. - oai:arXiv.org:2512.07889v1 - physics.flu-dyn + FuXi-Nowcast: Meet the longstanding challenge of convective initiation in nowcasting + https://arxiv.org/abs/2512.08974 + arXiv:2512.08974v1 Announce Type: new +Abstract: Accurate nowcasting of convective storms remains a major challenge for operational forecasting, particularly for convective initiation and the evolution of high-impact rainfall and strong winds. Here we present FuXi-Nowcast, a deep-learning system that jointly predicts composite radar reflectivity, surface precipitation, near-surface temperature, wind speed and wind gusts at 1-km resolution over eastern China. FuXi-Nowcast integrates multi-source observations, such as radar, surface stations and the High-Resolution Land Data Assimilation System (HRLDAS), with three-dimensional atmospheric fields from the machine-learning weather model FuXi-2.0 within a multi-task Swin-Transformer architecture. A convective signal enhancement module and distribution-aware hybrid loss functions are designed to preserve intense convective structures and mitigate the rapid intensity decay common in deep-learning nowcasts. FuXi-Nowcast surpasses the operational CMA-MESO 3-km numerical model in Critical Success Index for reflectivity, precipitation and wind gusts across thresholds and lead times up to 12 h, with the largest gains for heavy rainfall. Case studies further show that FuXi-Nowcast more accurately captures the timing, location and structure of convective initiation and subsequent evolution of convection. These results demonstrate that coupling three-dimensional machine-learning forecasts with high-resolution observations can provide multi-hazard, long-lead nowcasts that outperforms current operational systems. + oai:arXiv.org:2512.08974v1 physics.ao-ph - Wed, 10 Dec 2025 00:00:00 -0500 + cs.LG + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by-nc-nd/4.0/ - Dario P. Falcone, Matthew R. Igel, Joseph A. Biello - - - The effects of H blistering and ELMs on the thermal fatigue cracking of W by strikepoint sweeping - https://arxiv.org/abs/2512.07891 - arXiv:2512.07891v1 Announce Type: new -Abstract: Cyclic thermal loads imposed on a W divertor by strikepoint sweeping may induce low-cycle thermal fatigue cracking of its plasma-facing surfaces. This cracking may be accelerated by plasma-material interactions such as H implantation, blistering, fuzz and void formation. Fatigue cracking may also synergise with ELM cracking. To explore these novel forms of environmentally assisted fatigue, FEA modelling was used to design a uniaxial fatigue experiment for Magnum-PSI that represents strikepoint sweeping at 1 Hz across a 100 mm span of a divertor target. Magnum-PSI was used to combine cyclic thermal loading of W with H implantation and two forms of ELM like pre-cracking. Quantitative SEM analysis of fatigue-cracked W revealed that H implantation significantly delayed crack initiation, with preimplanted targets requiring 450-600 cycles before failure compared to 150 cycles for non-implanted samples. This was attributed to hydrogen-induced dislocation pinning, which produces a case-hardening effect that inhibits persistent slip band formation. ELM-like pre-cracking combined with strikepoint sweeping was found to give rise to localised melting and the formation of 30 micromete diameter droplets, caused by thermal isolation of W regions by fatigue cracks. The implications for the fatigue lifetime of tokamak divertors are also discussed. - oai:arXiv.org:2512.07891v1 - physics.plasm-ph - cond-mat.mtrl-sci - Wed, 10 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/licenses/by-sa/4.0/ - J. Hargreaves, J. Vernimmen, J. Scholten, T. W Morgan + Lei Chen, Zijian Zhu, Xiaoran Zhuang, Tianyuan Qi, Yuxuan Feng, Xiaohui Zhong, Hao Li - Kinetic Alfv\'en waves in the temperature anisotropic space plasma with a kappa-Maxwellian distribution - https://arxiv.org/abs/2512.07893 - arXiv:2512.07893v1 Announce Type: new -Abstract: The dispersion and damping rate of kinetic Alfv\'en waves are studied in temperature anisotropic space plasma with kappa-Maxwellian distribution. Employing a kinetic approach, the wave frequency and damping rate of kinetic Alfv\'en waves and the modified ion acoustic waves are derived in a low \b{eta} plasma, which both depend on the parameters \k{appa} and . The numerical analyses show that the wave frequency of kinetic Alfv\'en waves is larger in kappa-Maxwellian plasma than that in Maxwellian case. The wave frequency of the modified ion acoustic waves in kappa-Maxwellian plasma is larger in the short-wave region but smaller in the long-wave region than that in Maxwellian case. Again, we found that the damping rate of kinetic Alfv\'en waves in kappa-Maxwellian plasma is stronger than that in Maxwellian case. The damping rate of modified ion acoustic waves in kappa-Maxwellian plasma is stronger in the short-wave region but weaker in the long-wave region than that in Maxwellian case. The impact of the parameter on the two modes is relatively small because we consider the low \b{eta} case. These results are helpful for us to understand better the characteristics of kinetic Alfv\'en waves in space plasma. - oai:arXiv.org:2512.07893v1 - physics.plasm-ph - physics.space-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Ultra-trace analysis of U and Th in organic liquid scintillators with high sensitivity + https://arxiv.org/abs/2512.08988 + arXiv:2512.08988v1 Announce Type: new +Abstract: Rare event searches demand extremely low background levels, necessitating ever-advancing screening techniques to enhance sensitivity. Liquid scintillators are highly attractive as detector media due to their inherent radiopurity and scalability in mass. In this work, we present a screening procedure to measure ultra-trace concentrations of natural contaminants -- $^{238}$U and $^{232}$Th -- with sensitivities at the \qty{E-15}{g/g} level. Our method combines neutron activation analysis with radiochemical techniques, followed by \bg\ coincidence spectroscopy to minimize interference backgrounds. This approach achieves sensitivities of \qty{0.65E-15}{g/g} for $^{238}$U and \qty{2.3E-15}{g/g} for $^{232}$Th, among the best reported worldwide. Potential pathways for further sensitivity improvements are outlined in the conclusions. + oai:arXiv.org:2512.08988v1 + physics.ins-det + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Chin. J. Phys. 90 (2024) 199 - Rui Huo, Jiulin Du, Ran Guo + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + A. Barresi, D. Chiesa, D. Merli, M. Nastasi, S. Nisi, E. Previtali, M. Sisti, M. Borghesi, A. Cammi, C. Coletta, G. Ferrante, L. Loi, G. Andronico, V. Antonelli, D. Basilico, M. Beretta, A. Bergnoli, A. Brigatti, R. Brugnera, R. Bruno, A. Budano, B. Caccianiga, V. Cerrone, R. Caruso, C. Clementi, L. V. D'Auria, S. Dusini, A. Fabbri, G. Felici, A. Garfagnini, M. G. Giammarchi, N. Giudice, A. Gavrikov, M. Grassi, N. Guardone, F. Houria, C. Landini, L. Lastrucci, I. Lippi, P. Lombardi, F. Mantovani, S. M. Mari, A. Martini, L. Miramonti, M. Montuschi, D. Orestano, F. Ortica, A. Paoloni, L. Pelicci, E. Percalli, F. Petrucci, G. Ranucci, A. C. Re, B. Ricci, A. Romani, P. Saggese, A. Serafini, C. Sirignano, L. Stanco, E. Stanescu Farilla, V. Strati, M. D. C Torri, C. Tuve', C. Venettacci, G. Verde, L. Votano - Firehose instability in the space plasma with anisotropic Cairns-distribution electrons - https://arxiv.org/abs/2512.07894 - arXiv:2512.07894v1 Announce Type: new -Abstract: We study the electron firehose mode propagating parallel to the ambient magnetic field in the space plasma with anisotropic Cairns-distribution electrons. The dispersion relation, the wave frequency and the growth rate of electron firehose mode are derived, and the condition for onset of the firehose instability is obtained. We show that the wave frequency and the growth rate both depend significantly on the parameters, such as the parallel electron beta , the nonthermal parameter {\Lambda} and the electron temperature anisotropy Ae , and the anisotropic Cairns-distribution electrons change the instability condition. The numerical analyses show that the wave frequency and the growth rate of the electron firehose mode increase with increase of the parameters. The results may be helpful for understanding the firehose instability in space plasma environments. - oai:arXiv.org:2512.07894v1 - physics.plasm-ph + Tether-Based Architecture for Solar-Powered Orbital AI Data Centers + https://arxiv.org/abs/2512.09044 + arXiv:2512.09044v1 Announce Type: new +Abstract: We propose a tether-based structural architecture for orbital data centers operating in Dawn-Dusk Sun-Synchronous (DDSS) orbits under continuous sunlight. These space-based data centers, powered solely by solar energy, could provide multi-megawatt computing for artificial intelligence (AI) inference with minimal latency to Earth. The proposed design uses a tethered chain of computing nodes with photovoltaic panels to achieve uninterrupted 2-20 MW of computing power, and employs radiative cooling and integrated shielding to manage heat and radiation. We detail the system architecture, including mass budgets, passive attitude control, and the dynamics induced by micrometeoroid collisions. + oai:arXiv.org:2512.09044v1 physics.space-ph - Wed, 10 Dec 2025 00:00:00 -0500 + physics.app-ph + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Eur. Phys. J. Plus. 139 (2024) 604 - Rui Huo, Jiulin Du + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Igor Bargatin, Dengge Jin, Zaini Alansari, Jordan R. Raney - Ion-acoustic shock and solitary waves in magnetized plasma with Cairns-Gurevich distribution electrons - https://arxiv.org/abs/2512.07895 - arXiv:2512.07895v1 Announce Type: new -Abstract: The propagation properties of ion-acoustic solitary and shock waves in the magnetized viscous plasma with nonthermal trapped electrons are investigated. The Cairns-Gurevich distribution as the electron distribution is considered to describe the plasma nonthermality and particle trapping. By adopting the reductive perturbation technique, we derived the nonlinear Schamel-Korteweg-de Vries-Burgers (SKdVB) equation, and then obtained the ion-acoustic shock and solitary wave solutions of the SKdVB equation for different limiting cases. It is found that the impact of nonthermal parameter {\alpha}, external magnetic field {\Omega}, obliqueness lz, wave speed U0, and the ion kinematic viscosity {\eta}0 can significantly change the characteristics of the shock and solitary waves. These results may be useful for better understanding the propagation of nonlinear structures in space (i.e. Earth's magnetosphere and ionosphere, auroral regions) and laboratory plasma with nonthermal trapped electrons. - oai:arXiv.org:2512.07895v1 - physics.plasm-ph - physics.space-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Conserved Pseudomomenta in Linear Quasigeostrophic Fluid Flows From Noether's Theorem + https://arxiv.org/abs/2512.09061 + arXiv:2512.09061v1 Announce Type: new +Abstract: Hamiltonian and Lagrangian formulations for the two-dimensional quasi-geostrophic equations linearized about a zonally-symmetric basic flow are presented. The Lagrangian and Hamiltonian exhibit an infinite U(1) symmetry due to the absence of wave + wave -> wave interactions in the linearized approximation. By Noether's theorem the symmetry has a corresponding infinite set of conservation laws which are the well-known pseudomomenta. There exist separately conserved pseudomomenta at each zonal wavenumber, a point that has sometimes been obscured in past treatments. + oai:arXiv.org:2512.09061v1 + physics.flu-dyn + physics.ao-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Commun. Theor. Phys. 77 (2025) 065501 - Rui Huo, Jiulin Du + Dusan Begus, Chenyu Zhang, J. B. Marston - Analysis of the Sybil defense of Duniter-based cryptocurrencies - https://arxiv.org/abs/2512.07897 - arXiv:2512.07897v1 Announce Type: new -Abstract: Duniter-based cryptocurrencies, which are providing a kind of universal basic income, are using a system called "Web of Trust" based on a social network whose evolution is subject to graph theoretical rules, time constraints and a licence in order to avoid large Sybil attacks. We investigate in this article the largest size of a Sybil attack that a simplified version of the graph theoretical rules of a Web of Trust can undergo depending on the number of attackers and on the parameters of the system. We show that even if in theory, without considering social and time constraints, this system cannot in general prevent huge attacks, in the real-world case of a Duniter-based cryptocurrency (with thousands of users), the system can prevent attacks of large size with only graph theoretical rules. - oai:arXiv.org:2512.07897v1 - physics.soc-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Solvent-Directed Femtosecond Laser Ablation: Tuning Phase and Defect Engineering in Hybrid CdPS3/CdS Nanostructures + https://arxiv.org/abs/2512.09073 + arXiv:2512.09073v1 Announce Type: new +Abstract: The limited visible-light absorption of wide-bandgap van der Waals crystals fundamentally restricts their utility in solar energy conversion. Here, we report a surfactant-free, solvent-directed laser synthesis strategy to engineer the phase and optoelectronic properties of Cadmium Phosphorus Trisulfide (CdPS3). By exploiting the non-equilibrium thermodynamics of femtosecond pulsed laser ablation in liquid (fs-PLAL), we demonstrate a tunable transition from the stoichiometric ternary phase to a highly active binary-rich heterostructure. While ablation in water preserves the monoclinic CdPS3 lattice, the reducing environment of isopropanol triggers the formation of CdS quantum dots and metallic cadmium defect sites. This solvent-induced phase engineering transforms the ultraviolet-active host into a robust visible-light photocatalyst. The resulting hybrid CdPS3/CdS nanocolloids exhibit superior charge separation efficiency, driven by Schottky-like metal-semiconductor junctions, achieving ~ 90% degradation of Methylene Blue under 532 nm irradiation within 30 minutes. This work establishes fs-PLAL as a scalable defect-engineering tool for complex ternary layered materials, offering a new design of high-performance metal-thiophosphate-based photocatalysts. + oai:arXiv.org:2512.09073v1 + physics.app-ph + cond-mat.mtrl-sci + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Lucas Isenmann + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Andrei Ushkov, Nadezhda Belozerova, Gleb Tikhonowski, Stepan Klimov, Alexander Syuy, Sergey V. Bazhenov, Sergey Novikov, Vladimir G. Leiman, Aleksey Arsenin, Gleb I. Tselikov, Valentyn Volkov - A one-dimensional reduced plasma model for the electrical treeing - https://arxiv.org/abs/2512.07900 - arXiv:2512.07900v1 Announce Type: new -Abstract: Plasma models, consisting of advection-diffusion Partial Differential Equations coupled with chemical reactions, are widely adopted to describe corona, streamers and dielectric barrier discharges. However, the complex geometry of the electrical treeing represents an obstacle for numerical simulations. We develop a reduced one-dimensional formulation of a plasma model for the electrical treeing, describing the evolution of charge concentrations under the effect of an electric field. The reduced system consists of weakly coupled advection-diffusion-reaction equations for charge concentrations inside the treeing and on the dielectric surface, coupled with production-destruction Ordinary Differential Equations for the dipole moment. A numerical scheme based on Finite Volumes and Patankar-type methods allows efficient simulations, while preserving key physical properties. The model is tested on increasingly complex geometries, from a straight line to a realistic electrical treeing. - oai:arXiv.org:2512.07900v1 + Bayesian Optimization of Laser-Wakefield Acceleration via Spectral Pulse Shaping + https://arxiv.org/abs/2512.09125 + arXiv:2512.09125v1 Announce Type: new +Abstract: In this paper, we investigate the effect of spectral pulse shaping of the laser driver on the performance of channel-guided, laser-plasma accelerators. The study was carried out with the assistance of Bayesian optimization using particle-in-cell simulations. We used a realistic plasma profile based on a novel optical-field-ionized channel technique with ionization injection and low on-axis plasma densities to maximize the energy gain of the electron bunch trailing the laser. Spectral shaping allows us to modify the temporal profile of the laser driver while keeping the laser energy constant, affecting the acceleration and injection processes. Given the complexity and breadth of the parameter space in question, we used numerical optimization to identify high performers. In particular, we found laser profiles with additional spectral content that, when used with optimal plasma channel parameters, result in charge content an order of magnitude higher than the baseline Gaussian case while also increasing the mean energy of the electron bunch. + oai:arXiv.org:2512.09125v1 physics.plasm-ph - Wed, 10 Dec 2025 00:00:00 -0500 + math.OC + physics.acc-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Beatrice Crippa, Anna Scotti, Andrea Villa + B. Z. Djordjevi\'c, C. Benedetti, A. D. McNaughton, C. B. Schroeder, R. Lehe, H. -E. Tsai, S. C. Wilks, B. A. Reagan, G. J. Williams, J. van Tilborg - Schr\"odinger and Klein-Gordon oscillators in Eddington-inspired Born-Infeld gravity: Degree-one Confluent Heun polynomial correspondence - https://arxiv.org/abs/2512.07904 - arXiv:2512.07904v1 Announce Type: new -Abstract: We investigate Schr\"odinger and Klein-Gordon (KG) oscillators in the spacetime of a global monopole (GM) within Eddington inspired Born-Infeld (EiBI) gravity, including, in the relativistic sector, the coupling to a Wu-Yang magnetic monopole (WYMM). By reducing the radial equations to the confluent Heun form and enforcing termination of the Heun series, we obtain conditionally exact solutions in which the radial eigenfunctions truncate to polynomials of degree $(n+1)\geq 1$. This truncation imposes algebraic constraints that quantize the oscillator frequency and restrict the values allowed for the orbital angular momenta $\ell$. In the lowest nontrivial case $n=0$, the degree-one Heun polynomial yields a closed analytic expression for the frequency and determines a finite upper bound on $\ell$, dictated jointly by the EiBI deformation and the GM deficit. The resulting parametric correlations reveal a sharp geometric control of the spectrum: EiBI nonlinearities and the angular deficit fix the admissible bound states through polynomial truncation conditions. The confluent Heun correspondence is made explicit, providing a rigorous and reproducible framework for extracting analytical solutions from otherwise non-polynomial Heun structures. Applying the same method to the KG oscillator with a WYMM, we derive conditionally exact particle and antiparticle energies in a closed form. The relativistic spectrum exhibits perfect charge symmetry and a precise dependence on the WYMM strength, the EiBI parameter and the angular momentum constraint. To the best of our knowledge, this constitutes the first unified and fully consistent treatment of conditionally exact Schr\"odinger and Klein-Gordon oscillators in EiBI gravity based on a degree-one confluent Heun polynomial. - oai:arXiv.org:2512.07904v1 - physics.gen-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Accelerating high-order energy-stable discontinous Galerkin solver using auto-differentiation and neural networks + https://arxiv.org/abs/2512.09128 + arXiv:2512.09128v1 Announce Type: new +Abstract: High-order Discontinuous Galerkin Spectral Element Methods (DGSEM) provide excellent accuracy for complex flow simulations, but their computational cost increases sharply with higher polynomial orders. %that provide very accurate solutions. To alleviate these limitations, this work presents a differentiable DG solver coupled with neural networks (NNs) that learn corrective forcing terms to correct low-order simulations and provide high-order accuracy. The solver's full differentiability enables gradient-based optimization and interactive (solver-in-the-loop) training, mitigating the data-shift problem typically encountered in static, offline learning. Two representative test cases are considered: the one-dimensional viscous Burgers' equation and two-dimensional decaying homogeneous isotropic turbulence (DHIT). The results demonstrate that interactive training with extended unrolling horizons substantially improves the precision and long-term stability of the simulation compared to static training. For the Burgers' equation, a $\mathbb{P}_2$ simulation corrected using a NN-correction achieves the accuracy of a $\mathbb{P}_4$ solution with eight times reduction in computational cost. For the DHIT case, the NN-corrected low-order simulations successfully achieve high-order accuracy while reduce the error beyond the training interval. These results highlight the potential of differentiable solvers combined with neural networks as a robust and efficient framework for accelerating high-fidelity DG-based fluid simulations. + oai:arXiv.org:2512.09128v1 + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Omar Mustafa, Abdullah Guvendi + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Xukun Wang, Oscar A. Marino, Esteban Ferrer - Renewable Energies in the Agricultural Sector: A Perspective Analysis of the Last Three Years - https://arxiv.org/abs/2512.07905 - arXiv:2512.07905v1 Announce Type: new -Abstract: Over the last three years, research on the application of renewable energies in the agricultural sector has grown significantly. In this study, we conducted a bibliometric analysis of global scientific production from 2019 to 2021 to identify trends, leading contributors, and emerging research areas. Based on 1378 documents retrieved from Scopus, we observed a clear upward trend in publications, with a peak in 2021. India, China, the United States, Italy, and the United Kingdom were the most productive countries, while key institutions from China, Iran, and the Netherlands led the research output. Our results reveal five major thematic clusters: renewable energy technologies in agriculture, bioenergy, sustainable agriculture, biomass energy, and the environmental impact of agricultural activities. Notable advances include agrovoltaic systems, the use of agricultural and livestock waste for biogas production, and the development of agricultural robots powered by renewable energy sources. Additionally, there is increasing interest in examining the links among agriculture, renewable energy use, and greenhouse gas emissions, aligned with global sustainability goals. This analysis highlights the evolution of the field, international collaboration patterns, and the most influential research lines, offering valuable insights to guide future scientific developments in integrating renewable energies within the agricultural sector. - oai:arXiv.org:2512.07905v1 - physics.soc-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Simulating surfactant effects in phase-transforming fluids + https://arxiv.org/abs/2512.09140 + arXiv:2512.09140v1 Announce Type: new +Abstract: Surfactants are critical in natural processes and engineering, but measuring their concentrations in non-equilibrium conditions and in the presence of flow is difficult. Therefore, computational methods are a key tool for improving our understanding. Predicting the effect of surfactants on liquid-vapor transformations is particularly challenging due to (1) simultaneous mass transfer, non-equilibrium thermodynamics and Marangoni stresses, and (2) the phenomenological assumptions underlying many liquid-vapor phase-change models. Starting from the Navier-Stokes-Korteweg equations, a first-principles approach to liquid-vapor phase transformations, we developed a model of liquid-vapor flows with surfactants. We performed simulations of bubbles under equilibrium and liquid-vapor interface oscillations to demonstrate that the model successfully reproduces surfactant-mediated reductions in surface tension. We also investigated the mechanisms whereby surfactant affects bubble coalescence and condensation. Overall, this work provides a new framework for studying the effect of surfactants on liquid-vapor transformations and suggests multiple areas for future research, including the impact of complex surface chemistries on flow around bubbles and the acoustic response of bubbles with surfactants. + oai:arXiv.org:2512.09140v1 + physics.flu-dyn + physics.comp-ph + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - 10.3390/en16010345 - Energies 2023, 16(1), 345 - Quetzalcoatl Hernandez-Escobedo, David Mu\~noz-Rodr\'iguez, Alejandro Vargas-Casillas, Jos\'e Manuel Ju\'arez Lopez, Pilar Aparicio-Mart\'inez, Mar\'ia Pilar Mart\'inez-Jim\'enez, Alberto-Jesus Perea-Moreno + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Keyu Feng, Saikat Mukherjee, Tianyi Hu, Hector Gomez - Formal developments in curved momentum space: the quantum field theory roadmap - https://arxiv.org/abs/2512.07913 - arXiv:2512.07913v1 Announce Type: new -Abstract: We advocate that the dual picture of spacetime noncommutativity , i.e. the existence of a curved momentum space, could be a way out to solve some of the open conceptual problems in the field, such as the basis dependence of observables. In this framework, we show how to build deformed Klein--Gordon and Dirac equations. In addition, we give an outlook of how one could define quantum field theories, both free and interacting ones. - oai:arXiv.org:2512.07913v1 - physics.gen-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Binding Kinetics Oppositely Regulates type II Topoisomerase Relaxation and Decatenation Activities + https://arxiv.org/abs/2512.09141 + arXiv:2512.09141v1 Announce Type: new +Abstract: Type II Topoisomerases (topo II) are critical to simplify genome topology during transcription and replication. They identify topological problems and resolve them by passing a double-stranded DNA segment through a transient break in another segment. The precise mechanisms underpinning topo IIs ability to maintain a topologically simple genome are not fully understood. Here, we investigate how binding kinetics affects the resolution of two distinct forms of topological entanglement: decatenation and torsional relaxation. First, by single-molecule measurements, we quantify how monovalent cation concentration affects the dissociation rate of topo II from DNA. Second, we discover that increasing dissociation rates accelerate decatenation while slowing down relaxation catalytic activities. Finally, by using molecular dynamics simulations, we uncover that this opposite behaviour is due to a trade-off between search of target through facilitated diffusion and processivity of the enzyme in catenated versus supercoiled DNA. Thus, our findings reveal that a modulation of topo II binding kinetics can oppositely regulate its topological simplification activity, and in turn can have a significant impact in vivo. + oai:arXiv.org:2512.09141v1 + physics.bio-ph + cond-mat.soft + Thu, 11 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1088/1742-6596/2667/1/012069 - J.Phys.Conf.Ser. 2667 (2023) 1, 012069 - S. A. Franchino-Vi\~nas + http://creativecommons.org/licenses/by/4.0/ + Cleis Battaglia, Filippo Conforto, Yair Augusto Gutierrez Fosado, Matt Newton, Erin Cutts, Davide Michieletto, Antonio Valdes - Hydroacoustic Absorption and Amplification by Turbulence - https://arxiv.org/abs/2512.07920 - arXiv:2512.07920v1 Announce Type: new -Abstract: Acoustic waves propagating through fluid media are significantly influenced by turbulence. This paper experimentally investigates the influence of underwater turbulence on the propagation characteristics of acoustic waves, revealing that acoustic waves can be absorbed or amplified at frequencies far exceeding the turbulent fluctuation frequency. The maximum observed attenuation or amplification of received signals exceeds 60%, with no spectral broadening. The study covers two flow conditions: pipe flow and free jet, driven by either a pump or hydraulic head difference. Hydroacoustic transducers with frequencies ranging from 60 kHz to 4.4 MHz are used, while the wave propagation directions both parallel and perpendicular to the mean flow are considered. The variation trend and magnitude of received signals depend on wave frequency, amplitude and flow conditions. For each case, the amplitudes of all frequency components simultaneously decreases or increases under turbulence, with no new spectral components appearing. After closing the flow control valve, the receiver signal requires a finite time to stabilize to its quiescent-state value. In contrast, suction near the pipe outlet shows that laminar flow has no effect on acoustic signals, confirming that the primary cause of signal variation is turbulent fluctuations rather than mean flow. Comparison with conventional theories and experiments indicates that mechanisms such as bubbles, resonance, scattering, or viscous dissipation cannot explain the observed phenomena. This suggests the existence of a previously unknown interaction mechanism between turbulence and acoustic waves. - oai:arXiv.org:2512.07920v1 + Predictive Compressibility Transformation for Hypersonic Turbulent Boundary Layers with Cold Walls + https://arxiv.org/abs/2512.09147 + arXiv:2512.09147v1 Announce Type: new +Abstract: Compressibility transformations are used to relate hypersonic zero-pressure-gradient (ZPG) turbulent boundary layers (TBLs) to incompressible reference states, but their assessment has largely focused on the collapse of transformed mean velocity profiles, without enforcing a unique, Mach-independent representation of the mean shear. In this work, a stricter consistency condition is proposed, requiring that a single incompressible inner-outer model for the mean velocity gradient reproduce all transformed compressible profiles when expressed in terms of a transformed wall-normal coordinate. This implies collapse not only of the transformed mean velocity but also of semilocal eddy viscosity and TKE production. Existing compressibility transformations are shown, using hypersonic DNS, to incur velocity errors of 1-25% relative to the incompressible inner-outer model, particularly for strongly cooled cases. A new forward compressible-to-incompressible transformation is developed that constructs the transformed coordinate as a convex combination of semilocal and integral-type basis functions with coefficients modeled as functions of friction Mach number and wall heat transfer rate. Casewise optimization yields consistency errors of 1-4% across the available hypersonic DNS set, and this performance is retained using multi-linear and multi-quadratic regressions. The forward transformation is embedded in an inverse incompressible-to-compressible transformation framework, which reconstructs the compressible state from freestream and wall conditions at a prescribed BL thickness. The inverse solver recovers key BL parameters, velocity profiles, and skin friction distributions with good accuracy, and generally improves upon existing models for cold-wall hypersonic TBLs, thereby providing a physically constrained basis for near-wall modeling in hypersonic TBLs with strong wall cooling. + oai:arXiv.org:2512.09147v1 physics.flu-dyn - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Kai-Xin Hu, Yue-Jin Hu + http://creativecommons.org/licenses/by/4.0/ + Engin Danis - Measuring the group velocity dispersion in near resonant hot atomic vapors - https://arxiv.org/abs/2512.07954 - arXiv:2512.07954v1 Announce Type: new -Abstract: Group velocity dispersion (GVD) in near-resonant hot atomic vapors is difficult to measure with standard pulse broadening or interferometric techniques, as absorption, pulse distortion and nonlinearities strongly affect the probe and reduce the signal-to-noise ratio. We introduce a simpler method using a continuous-wave laser with weak phase modulation and a slow photodetector, directly inspired by Bragg-like spectroscopy in fluids of light. During propagation, the red and blue-detuned sidebands accumulate different dispersive phase shifts, leading to oscillations in the transmitted modulation contrast as the modulation frequency is scanned. Vanishing contrast at well-defined frequencies directly yields the GVD. We apply this technique to hot rubidium vapors and observe the strong frequency dependence of the GVD across a broad detuning range of the D2 line at different temperatures. - oai:arXiv.org:2512.07954v1 + Freely controllable single-optical-frequency comb for highly sensitive cavity ring-down spectroscopy + https://arxiv.org/abs/2512.09159 + arXiv:2512.09159v1 Announce Type: new +Abstract: Direct comb spectroscopy is a useful tool for obtaining highly accurate spectroscopic information. However, as the number of comb modes is very large and the optical energy is dispersed over them, the optical energy per each comb mode is ultrasmall, limiting the sensitivity of highly sensitive spectroscopy. If we can concentrate the optical energy into the comb modes that only overlap with the absorption spectra, we can demonstrate drastic improvements in its measurement sensitivity. In this study, we developed a freely controllable optical frequency comb source based on the spectral peak phenomenon. The comb modes overlapping the CH4 absorption spectra were transformed into background-suppressed spectral peaks at the nonlinear loop mirror using a CH4 gas cell. Coherence-preserving power scaling of the generated comb was demonstrated using a fiber Raman amplifier. Subsequently, only the single-comb mode was filtered using a newly developed spectral filter with an ultrahigh resolution. The maximum optical power of a single comb was estimated to be more than 10 mW. The ring-down decay signal from the high-finesse optical cavity was measured using a single selected mode of the generated controllable comb. As a demonstration, the 2v_3 bands of the CH4 absorption spectra were accurately measured by comb-mode-resolved, cavity ring-down spectroscopy (CRDS) with high sensitivity up to 4.2 x 10^(-11) cm^(-1). This sensitivity is two orders of magnitude higher than that of previously reported comb-based CRDS. The residual was only 0.29 %, indicating the high accuracy of the proposed spectrometer for molecular spectral analysis. This approach can be extended to other wavelength ranges and is useful for highly sensitive, high-resolution, comb-resolved spectroscopy. + oai:arXiv.org:2512.09159v1 physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Alix Merolle, Quentin Glorieux + Norihiko Nishizawa, Shotaro Kitajima, Ningwu Liu, Ryohei Terabayashi, Daiki Hashimoto, Hisashi Abe, Hideki Tomita - Watt-level second harmonic generation in periodically poled thin-film lithium tantalate - https://arxiv.org/abs/2512.07968 - arXiv:2512.07968v1 Announce Type: new -Abstract: Second-harmonic generation (SHG) is a fundamental tool in modern laser technology, enabling coherent frequency conversion to remote optical bands, serving as the basis for self-referenced femtosecond lasers and quadrature-squeezed light sources. State-of-the-art SHG relies on bulk crystals and ridge waveguides, although continuous-wave (CW) SH efficiency in bulk crystals is limited by short interaction lengths and large mode areas. Ridge waveguides offer better performance with lower pump power requirements, yet must span several centimeters to deliver high output power, complicating fabrication and narrowing the bandwidth. Recently, SHG in periodically poled thin-film lithium niobate integrated photonic circuits has attracted significant interest, offering orders-of-magnitude improvement in SHG under CW pumping due to the stronger optical mode confinement. However, lithium niobate has a low optical damage threshold, even in MgO-doped substrates, which limits SH power output to well below the watt level. Here, we overcome this challenge and demonstrate 7 mm-long periodically poled thin-film lithium tantalate (PPLT) waveguides that achieve high SH output in the CW regime, with generated power exceeding 1 W and off-chip output above 0.5 W at 775 nm under 4.5 W pump power. PPLT offers a higher optical damage threshold than PPLN and supports watt-level operation. By optimizing electrode geometry and poling conditions, we obtain reproducible poling despite lithium tantalate's coercive field being nearly four times higher than that of MgO-doped lithium niobate. Although its effective nonlinearity is more than five times lower, we achieve watt-level CW output with a short waveguide, demonstrating the potential of PPLT circuits for high-power applications in integrated lasers, quantum photonics, AMO physics, optical clocks, and frequency metrology. - oai:arXiv.org:2512.07968v1 - physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + The skin effect in anomalous transport of charged particles in plasma with a microturbulent magnetic field. I. Isotropic plasma + https://arxiv.org/abs/2512.09168 + arXiv:2512.09168v1 Announce Type: new +Abstract: The influence of electromagnetic skin effect on anomalous charged particle transport in dense, non-relativistic, collisionless plasma with a small-scale turbulent magnetic field was investigated using quasi-linear kinetic equations, through both analytical and numerical methods. Analytical expressions for the diffusion tensor components in the Fokker-Planck equation that take this effect into account have been found. The equation was solved numerically in the case of magnetostatic turbulence. It has been demonstrated that the skin effect increases the mean free path of particles in turbulent plasma, thereby reducing its anomalous resistance. It also leads to anisotropy in particle scattering, resulting in anisotropy in their stationary velocity distribution, which increases as the screening parameter grows. Approximate analytical formulas for the effective mobility of charged particles and the electric conductivity of plasma with isotropic magnetostatic turbulence have been obtained. + oai:arXiv.org:2512.09168v1 + physics.plasm-ph + physics.space-ph + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Nikolai Kuznetsov, Zihan Li, Tobias J. Kippenberg + http://creativecommons.org/licenses/by/4.0/ + N. A. Emelyanov, Vl. V. Kocharovsky - On the accuracy of population level approximation of network processes - https://arxiv.org/abs/2512.07995 - arXiv:2512.07995v1 Announce Type: new -Abstract: The individual-based model of simple contagion processes is considered on regular graphs. This model explicitly incorporates the adjacency matrix of the network enabling us to study the effect of network structure on the dynamic of the propagation process. While the asymptotic behaviour of the model is well known, the transient behaviour has been less studied. Our goal in this paper is to give a theoretical estimate on the accuracy of the one-dimensional population-level approximation. This is carried out for arbitrary simple contagion processes and regular Tur\'an graphs. Numerical evidence is shown that the theoretical estimate is rather sharp for dense graphs. - oai:arXiv.org:2512.07995v1 - physics.soc-ph - math.DS - Wed, 10 Dec 2025 00:00:00 -0500 + The choice of viscous or viscoelastic models affects attenuation and velocity determination in simplified skull-mimicking digital phantoms + https://arxiv.org/abs/2512.09173 + arXiv:2512.09173v1 Announce Type: new +Abstract: Simulation-guided transcranial focused ultrasound therapies rely on estimating skull acoustic properties from pretreatment imaging. Typical clinical resolution (0.5 mm isotropic) cannot resolve bone microstructure, making the acoustic properties underdetermined and sensitive to modeling assumptions. Here, we examine how viscous and viscoelastic models predict changes in attenuation and phase velocity due to microstructure. Using viscous and viscoelastic k-Wave implementations, we simulated transmission of a broadband 625 kHz tone burst (250 kHz-1 MHz) through skull-mimicking digital phantoms. The phantoms contained spherical pores (0.1-1.0 mm diameter) randomly embedded within cortical bone (2.5%-90% porosity). Virtual sensors measured attenuation and phase velocity using a time-distance matrix approach. Both models predict increased attenuation with increasing pore size at a fixed porosity, but differ in the strength and porosity dependence of this relationship. The viscoelastic model generally predicts attenuation peaks at higher porosities than the viscous model. For 1.0 mm pores, the viscous peak (1.98 Np/cm) occurs at 20% porosity, while the viscoelastic peak (2.98 Np/cm) occurs at 70%. Phase velocity decreases with pore size for both models, though the viscoelastic predictions are less sensitive to pore size. These results demonstrate that viscous and viscoelastic models exhibit distinct attenuation and phase-velocity behavior for idealized bone microstructures. While both indicate that microstructure has a strong impact on attenuation, it has a lesser effect on phase velocity for the viscoelastic model compared to the viscous model. This work highlights the importance of acoustic model choice when estimating skull acoustic properties from computed tomography images. Future work will identify which acoustic model best represents ultrasound propagation through skull microstructure. + oai:arXiv.org:2512.09173v1 + physics.med-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by-nc-nd/4.0/ - No\'emi Nagy, S\'andor Horv\'ath, Bal\'azs Maga, P\'eter L. Simon + Samuel Clinard, Taylor Webb, Henrik Od\'een, Dennis L. Parker, Douglas A. Christensen - ALS Storage Ring RF Control System Upgrade Plan and Status - https://arxiv.org/abs/2512.07996 - arXiv:2512.07996v1 Announce Type: new -Abstract: The Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory, a third-generation synchrotron light source operational since 1992, is undergoing a comprehensive upgrade of its storage ring RF control system. The legacy Horner PLC controllers and remote I/O modules, now at end-of-life, are being replaced with an Allen-Bradley PLC platform to improve maintainability, reliability, and long-term support. This paper presents the planning, design, and current status of the upgrade project. - oai:arXiv.org:2512.07996v1 - physics.acc-ph - cs.SY - eess.SY - Wed, 10 Dec 2025 00:00:00 -0500 + Aerodynamic Forces on a Wing Surfing in a Two-dimensional Vortex Wake + https://arxiv.org/abs/2512.09184 + arXiv:2512.09184v1 Announce Type: new +Abstract: Inspired by the wake-surfing nature of animals, this study aims to understand the aerodynamic force variation on a wing surfing in an unsteady 2-D wake. Wind tunnel experiments were conducted using Particle Image Velocimetry (PIV) and force measurements with a fixed wing immersed in the wake of a pitching airfoil. The comparison between force and PIV measurements shows that the lift response of the surfing wing is aligned with the impingement of flow structures, and that the dependence of the cycle-averaged lift fluctuations on the upstream flapping kinematics can be scaled as a function of the reduced amplitude and reduced frequency of the flapping motion. Good collapse of the data is found, and deviations from scaling are explained in terms of the wake characteristics. The phase-resolved lift fluctuations on the vortical wake encountering can be effectively predicted using classic unsteady aerodynamics based on measured unsteady local flow conditions (instantaneous angle of attack and speed). The theoretical predictions compare well with direct force sensor measurements. + oai:arXiv.org:2512.09184v1 + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - 10.18429/jacow-icalepcs2025-tupd030 - ICALEPCS 2025 - Najm Us Saqib, Angel Jurado, Esteban Andrade, Qiang Du, Jeong Han Lee, Miroslaw Dach, Benjamin Flugstad + http://creativecommons.org/licenses/by-sa/4.0/ + Siyang Hao, Kenneth Breuer - Robust External-Beam Calibration of Plastic Scintillation Detectors for In-Vivo Dosimetry in HDR Brachytherapy - https://arxiv.org/abs/2512.08014 - arXiv:2512.08014v1 Announce Type: new -Abstract: Purpose: HDR brachytherapy is a widely adopted modality for cancer treatment. However, it is not free from error and uncertainty. In-vivo dosimetry (IVD) is the only technique that can confirm correct dose delivery. This study details and validates a calibration method for Plastic Scintillation Detector (PSD), bypassing dose gradient and positioning issues in brachytherapy calibration. Methods: The PRB-0057 PSD (Medscint, Canada) was calibrated, 1x1 mm scintillating fiber coupled to a 20 m Eska GH-4001 clear optical fiber (Mitsubishi Rayon, Japan). The fiber is connected to the Hyperscint-RP200 research platform for signal collection. Hyperspectral calibration was performed at a LINAC with a 6 MV beam, enabling removal of stem effects before brachytherapy measurements. For validation, an Iridium-192 Flexisource (Elekta Brachy, The Netherlands), Sk=29447U, was used in a motorized IBA-Blue-Phantom2 water tank (48x48x41cm3). Dose rates were measured at 10 Hz along the source z-axis at a fixed transverse distance of 1.2+/-0.05 cm in 0.2 cm steps. Relative difference (RD) between measured and TG-43U1 dose rates was assessed. A detailed uncertainty budget was associated with brachytherapy measurements. Results: Comparison shows good agreement with RD around 2.5 $\%$ at 1.2 cm, corresponding to positional uncertainties of <0.15 mm. At greater depths up to 8 cm, RDs increase to about 5 $\%$, mainly due to reduced light yield. Uncertainties depend on the source-detector distance, ranging from 3.81 to 6.39 $\%$ (k=1) over the explored range. Conclusions: Results confirm the PSD calibration effectiveness using a 6MV external beam with hyperspectral technique. Uncertainties close to the source align with positional errors and are dominated by reduced PSD sensitivity at larger distances. The study underlined the intrinsic limitation of IVD in the face of known uncertainties. - oai:arXiv.org:2512.08014v1 - physics.med-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Deep Learning Surrogates for Gas Dynamics: A Physics-Informed Pedagogical Approach + https://arxiv.org/abs/2512.09193 + arXiv:2512.09193v1 Announce Type: new +Abstract: Compressible flow problems are characterized by highly nonlinear, implicit, and often transcendental governing equations. In undergraduate gas dynamics educa- tion, solving these equations traditionally relies on iterative numerical methods or extensive look-up tables, which can obscure the physical intuition of the solution space. This paper introduces a comprehensive framework using Deep Learning to generate high-fidelity surrogate models for five canonical problems: Rayleigh flow, Fanno flow, oblique shocks, convergent-divergent nozzles, and unsteady shock tubes. We detail the specific neural network architectures and physics-informed feature en- gineering strategies required for each problem, such as using logarithmic inputs for Fanno friction parameters or geometric anchors for oblique shocks. The resulting models achieve high accuracy and enable instantaneous visualization of complex design spaces, such as thermodynamic T s diagrams and unsteady x t wave interactions. This approach demonstrates how modern data-driven techniques can be integrated into the physics curriculum to enhance conceptual understanding. + oai:arXiv.org:2512.09193v1 + physics.flu-dyn + physics.ed-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Chahrazed Ghannoudi, Marie-Claude Lavallee, Benjamin Cote, Luc Beaulieu + Ehsan Roohi - Overview of the Helios Design: A Practical Planar Coil Stellarator Fusion Power Plant - https://arxiv.org/abs/2512.08027 - arXiv:2512.08027v1 Announce Type: new -Abstract: Thea Energy, Inc. has developed the preconceptual design for "Helios," a fusion power plant based on the planar coil stellarator architecture. In this overview paper, the design is summarized and the reader is referred to the other papers for more detail. The Helios design is based around a two-field-period quasi-axisymmetric ("QA") stellarator equilibrium with aspect ratio 4.5 and a novel tokamak-like X-point divertor. The natural stability, low recirculating power, and steady-state capability of the stellarator are leveraged. Stability and transport are calculated using state-of-the-art, high-fidelity codes and grounded in measured performance of existing experiments. The electromagnetic coil set is high-temperature superconducting ("HTS") and consists of 12 large, plasma-encircling coils like the toroidal field coils of a tokamak, and 324 smaller, field-shaping coils. All coils are planar and convex. A maximum of 20 T on-coil is enforced, a value which has been achieved in existing large-bore HTS coils. There is a minimum of 1.2 m between plasma and coils, leaving space for tritium breeding blanket and neutron shielding. Because of this thick shielding, all coils have a minimum 40-year operational lifetime, the same minimum lifetime of the power plant system. 1.1 GW of thermal power and 390 MW of net electric power are produced. The shaping coils are individually controllable, enabling a uniquely configurable magnetic field for relaxed manufacturing and assembly tolerances and plasma control. A practical maintenance architecture is a primary driver of the design; maintenance is performed on entire toroidal sectors that are removed from between the encircling coils. A biennial maintenance cycle is estimated to take approximately 84 days, resulting in an 88% capacity factor. Rigorous engineering constraints such as temperature and stress limits are enforced. - oai:arXiv.org:2512.08027v1 + Activation of Polylactic Acid and Polycarbonate Surfaces with Non-Thermal Plasma + https://arxiv.org/abs/2512.09205 + arXiv:2512.09205v1 Announce Type: new +Abstract: Non-thermal plasma (NTP) surface activation has become a powerful and versatile strategy to engineer the interfacial properties of biomedical polymers whose intrinsic hydrophobicity limits their biological performance. In polymers such as polylactic acid (PLA) and polycarbonate (PC), NTP promotes the controlled incorporation of polar functional groups, increases surface energy, modifies dielectric behavior, and generates micro-roughness that collectively enhance protein adsorption and early cell adhesion. This review synthesizes and critically evaluates evidence across four complementary analytical pillars-contact-angle theory, dielectric impedance spectroscopy, FT-IR chemical mapping, and optical microscopy-to construct an integrated framework for interpreting plasma-induced chemical and morphological transformations. + The convergence of multimodal results demonstrates that NTP consistently produces chemically active, polar, and moderately textured surfaces that support robust initial cell-material interactions. Furthermore, combining wettability, dielectric, and spectroscopic analysis enables the identification of activation pathways, the assessment of hydrophobic recovery dynamics, and the development of quantitative correlations between dielectric parameters and biological response. However, the literature also reveals key methodological gaps, including the limited use of unified multimodal protocols, insufficient evaluation of temporal stability, and a lack of predictive dielectric-biological models. + By articulating these advances and limitations within a unified conceptual scheme, this review provides a roadmap for future research aimed at standardizing characterization workflows and enabling the rational design of next-generation plasma-functionalized biomaterials for tissue-engineering scaffolds, implantable devices, and advanced drug-delivery systems. + oai:arXiv.org:2512.09205v1 physics.plasm-ph - Wed, 10 Dec 2025 00:00:00 -0500 + cond-mat.mtrl-sci + physics.bio-ph + Thu, 11 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - C. P. S. Swanson, S. T. A. Kumar, D. W. Dudt, E. R. Flom, W. B. Kalb, T. G. Kruger, M. F. Martin, J. R. Olatunji, S. Pasmann, L. Z. Tang, J. von der Linden, J. Wasserman, M. Avida, A. S. Basurto, M. Dickerson, N. de Boer, M. J. Donovan, A. H. Doudn Cate, D. Fort, W. Harris, U. Khera, A. Koen, J. A. Labbate, N. Maitra, A. Ottaviano, R. K. Parmar, E. J. Paul, B. Reydel, A. van Riel, P. K. Romano, M. Savastianov, S. Saxena, S. Seethalla, S. Srinivasan, R. H. Wu, D. Nash, J. Priebe, M. Slepchenkov, S. Walsh, B. Berzin, D. A. Gates, the Thea Energy team + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Jairo Rond\'on, Ginger Urrutia, Angel Gonzalez-Lizardo - Metabolic rate beyond the 3/4 law - https://arxiv.org/abs/2512.08031 - arXiv:2512.08031v1 Announce Type: new -Abstract: This work presents a discrete theoretical model in which basal metabolic rate \(B\) is described as a dynamic function of an organism's ontogenetic stage \(n\). Instead of treating \(B\) only as a static function of body mass \(M\), we adopt the form \(B(n) = B_0 \, M^{\,b(n)}\), in which the effective scaling exponent \(b(n)\) varies systematically throughout development. In contrast to classical approaches, such as Kleiber's empirical law (\(B \propto M^{3/4}\)) and the continuous fractal model of West--Brown--Enquist (WBE), which assume a constant exponent, the present framework emphasizes how the metabolic scaling relationship itself can evolve over the life cycle of a single individual. The model is inspired by a Fibonacci-based description of growth in discrete stages, leading to analytic expressions for \(b(n)\) that connect ontogenetic progression to changes in the scaling between metabolism and mass. In this setting, Kleiber's constant \(B_0 \approx 70\) kcal/day is reinterpreted as a \emph{metabolic anchoring point}, linking the classical law \(B \approx 70\,M^{3/4}\) to a developmentally explicit formulation. We show that the resulting trajectory \(B(n)\) captures, at a conceptual level, how metabolic scaling can shift from strongly sublinear behavior at early stages towards an almost linear regime as \(n\) increases, and that the predicted basal rates remain compatible, in order of magnitude, with values reported for mammals of different sizes. In this way, the work offers a unified framework that connects the evolution of \(B(n)\) across ontogeny to the recursive organization of biological growth. - oai:arXiv.org:2512.08031v1 - physics.bio-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Evaluating the Impact of Population Growth and Applying Decarbonization Regulations on the Energy Market in the ERCOT Interconnection Area + https://arxiv.org/abs/2512.09227 + arXiv:2512.09227v1 Announce Type: new +Abstract: Texas ERCOT is experiencing rapid population growth that increases electricity demand and creates new reliability challenges. At the same time, decarbonization policies are being considered, adding uncertainty about future generation portfolios and system costs. This study evaluates how population driven load growth and proposed decarbonization regulations may affect ERCOT in 2030 using a capacity expansion model. Three population scenarios are analyzed: baseline, lower growth, and higher growth. For each scenario, additional cases introduce a CO2 emissions limit and a carbon price to assess their effects on system costs, generation mix, and non served energy. + Results show that population growth increases total system costs and unmet demand, while storage needs and transmission transfer levels remain relatively stable. A CO2 emissions limit has almost no effect because ERCOT is already expected to meet the 2030 threshold. In contrast, carbon pricing produces a meaningful shift toward renewable generation and reduced use of natural gas, although cost impacts vary by scenario. These findings show the importance of accounting for demographic uncertainty in long term planning and suggest that carbon pricing may be a more effective decarbonization mechanism than static emissions limits. The study also provides a basis for future stochastic modeling that incorporates uncertainty in demand, renewable output, and fuel prices. + oai:arXiv.org:2512.09227v1 + physics.soc-ph + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Dorilson Silva Cambui + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Farah Altarazi - Ab initio study of highly charged ion-induced Coulomb explosion imaging - https://arxiv.org/abs/2512.08102 - arXiv:2512.08102v1 Announce Type: new -Abstract: We present a theoretical investigation of ion-induced Coulomb explosion imaging (CEI) of pyridazine molecules driven by energetic C$^{5+}$ projectiles, using time-dependent density-functional theory (TDDFT) with Ehrenfest nuclear dynamics. By systematically varying the projectile's impact point and orientation relative to the molecular plane, we compare orthogonal and in-plane trajectories and quantify their effects on fragment momenta, electron-density response, and atom-resolved ionization. Newton plots and time-resolved density snapshots show that trajectories avoiding direct atomic collisions yield the most faithful structural reconstructions, whereas direct impacts impart large, highly localized momenta that distort the recovered geometry. Planar trajectories generate substantially greater ionization and broader momentum distributions than orthogonal ones due to deeper traversal through the molecular electron cloud. Quantitative analysis of electron removal at 10~fs confirms that projectile proximity and orientation strongly modulate both local and global ionization. These findings clarify how impact geometry governs the fidelity of ion-induced CEI structural recovery and help explain the variability and noise observed in experimental CEI measurements. More broadly, the results highlight both the strengths and the intrinsic limitations of ion-induced CEI and identify key considerations for interpreting experiments. - oai:arXiv.org:2512.08102v1 - physics.chem-ph - quant-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Non-invasive Techniques for Flow Rate Measurement in Water Pipes: Protocol for a Systematic Review + https://arxiv.org/abs/2512.09239 + arXiv:2512.09239v1 Announce Type: new +Abstract: Accurate, non-invasive flow measurement is imperative for efficient water resource management and leak detection in distribution systems. Despite the advent of diverse external sensing technologies, a paucity of consolidated evidence exists regarding their comparative performance, energy efficiency, and applicability in varied operational contexts. The document delineates the protocol for a systematic literature review (SLR) that aims to identify, evaluate, and synthesize the extant evidence on non-invasive flow monitoring techniques for piped networks. Adhering to the Kitchenham methodology, the review will investigate the accuracy, precision, and energy consumption of prevailing solutions, such as ultrasonic and accelerometer-based systems. The analysis will also assess the impact of signal processing and machine learning (ML) algorithms on enhancing system capabilities. The objective of this study is to map the state-of-the-art, identify key research gaps, and provide an empirical foundation to direct future research toward operational deployment. + oai:arXiv.org:2512.09239v1 + physics.ins-det + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Misa Viveiros, Samuel S. Taylor, Cody Covington, K\'alm\'an Varga + Juan Diego Belesaca, Fabian Astudillo Salinas - Applicability of Metalenses for Generalizable Computer Vision - https://arxiv.org/abs/2512.08109 - arXiv:2512.08109v1 Announce Type: new -Abstract: Optical neural networks (ONNs) are gaining increasing attention to accelerate machine learning tasks. In particular, static meta-optical encoders designed for task-specific pre-processing demonstrated orders of magnitude smaller energy consumption over purely digital counterpart, albeit at the cost of slight degradation in classification accuracy. However, a lack of generalizability poses serious challenges for wide deployment of static meta-optical front-ends. Here, we investigate the utility of a metalens for generalized computer vision. Specifically, we show that a metalens optimized for full-color imaging can achieve image classification accuracy comparable to high-end, sensor-limited optics and consistently outperforms a hyperboloid metalens across a wide range of sensor pixel sizes. We further design an end-to-end single aperture metasurface for ImageNet classification and find that the optimized metasurface tends to balance the modulation transfer function (MTF) for each wavelength. Together, these findings highlight that the preservation of spatial frequency-domain information is an essential interpretable factor underlying ONN performance. Our work provides both an interpretable understanding of task-driven optical optimization and practical guidance for designing high-performance ONNs and meta-optical encoders for generalizable computer vision. - oai:arXiv.org:2512.08109v1 - physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + Isotope Production in Fusion Systems + https://arxiv.org/abs/2512.09242 + arXiv:2512.09242v1 Announce Type: new +Abstract: Fusion systems producing isotopes via neutron-driven transmutation can achieve economic viability well before reaching energy breakeven. Incorporating carefully selected feedstock materials within the blanket allows fusion systems to generate both electrical power and high-value isotopes, expanding the space of viable concepts, significantly enhancing the economic value of fusion energy, and supporting an accelerated path to adoption. We calculate the value of this co-generation and derive a new economic breakeven condition based on net present value. At lower plasma gain, $Q_{\mathrm{plas}}\lesssim1-3$, high-value transmutation, such as medical radioisotopes, enables pure transmuter fusion systems operating at only a few megawatts of fusion power: for example, a 3 megawatt system transmuting ${}^{102}\mathrm{Ru}\rightarrow{}^{99}\mathrm{Mo}$ could fulfill global ${}^{99}\mathrm{Mo}$ demand with $Q_{\mathrm{plas}}\ll1$. At higher gain $Q_{\mathrm{plas}}\gtrsim3$, it becomes viable to generate electricity in addition to isotopes. For example, co-production of electricity and gold, transmuted from mercury in a fusion blanket, can reduce the required plasma gain for viability from $Q_{\mathrm{plas}}\sim10-100$ to $Q_{\mathrm{plas}}\sim3-5$. We further highlight techniques to enhance transmutation including magnetic mirrors, asymmetric neutron wall loading, and neutron multiplication. Fusion neutron-driven transmutation therefore offers a revenue-positive pathway for deploying fusion energy at terawatt-scale, starting from smaller megawatt-scale machines for radioisotope production and then scaling up to co-producing electricity and gold in larger fusion power plants. + oai:arXiv.org:2512.09242v1 + physics.plasm-ph + nucl-ex + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Yubo Zhang, Johannes Fr\"och, Jinlin Xiang, Shane Colburn, Myunghoo Lee, Zhihao Zhou, Minho Choi, Eli Shlizerman, Arka Majumdar + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + J. F. Parisi, J. A. Schwartz, S. E. Wurzel, A. Rutkowski, J. Harter - FRINGE: a protocol for self-referenced quantum state estimation via photon-number-resolved interferometry - https://arxiv.org/abs/2512.08127 - arXiv:2512.08127v1 Announce Type: new -Abstract: We introduce a self-referenced method for quantum-state tomography of light based on photon-number-resolved double-slit interferometry. Two identical copies of the unknown quantum field illuminate laterally displaced slits, guaranteeing perfect spatiotemporal mode matching without a separate local oscillator. In the far-field, detection at transverse position $x$ is associated with a relative slit phase $\phi(x)$, and an $N$-photon event projects the detected quantum field onto a state $|N;\phi(x)\rangle$. The resulting distribution $P(N,\phi)$ is the quantum analogue of a Frequency Resolved Optical Gating (FROG) trace: whereas FROG reconstructs the classical complex spectral field $E(\omega)$ from a spectrally resolved second harmonic of a pulse with its delayed self, our measurement reconstructs the Fock-space wavefunction or density matrix from binomially weighted self-interference. The scheme requires no known or mode-matched reference and is compatible with commercially available photon-number-resolving cameras. Beyond conceptual simplicity and automatic mode matching, the FROG analogy permits direct transfer of mature ultrafast-optics methodologies (e.g., mixed-state, ptychographic, and vectorial extensions) into quantum optics, offering a versatile route to tomography of quantum photon states. - oai:arXiv.org:2512.08127v1 - physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + On How Zonal Fields Suppress Reversed Shear Alfv\'en Eigenmode in Tokamak Plasmas + https://arxiv.org/abs/2512.09243 + arXiv:2512.09243v1 Announce Type: new +Abstract: Employing both nonlinear gyrokinetic simulations and theoretical analyses, we have discovered the novel result that, with energetic particle dynamics kept linear, the nonlinear suppression and eventual saturation of reversed-shear Alfv\'en eigenmode occur via the downward frequency chirping induced by the beat-driven zonal current. More specifically, as the mode frequency chirps downward, there is enhanced mode conversion to radially propagating electron Landau-damped kinetic Alfv\'en waves; resulting in enhanced convective (radiative) damping and, thereby, its suppression and saturation. Theoretical results are in good agreement with simulations both qualitatively and quantitatively. + oai:arXiv.org:2512.09243v1 + physics.plasm-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Matan Even Tzur + Ruirui Ma, Pengfei Liu, Liu Chen, Fulvio Zonca, Zhiyong Qiu - Single-step laser patterning and thinning of biocompatible MEMS flow sensor - https://arxiv.org/abs/2512.08128 - arXiv:2512.08128v1 Announce Type: new -Abstract: Micro-electro mechanical systems (MEMS) thermal flow sensors are increasingly used for compact, low-power flow monitoring in biomedical applications. However, silicon-based method for sensor fabrication is limited by high cost, rigidity, and multi-step cleanroom processes. This study presents a single-step fiber laser micromachining method for fabricating biocompatible, free-standing MEMS thermal flow sensors from ultrathin titanium foil. The process combines patterning and localized thinning in single-step process, with titanium serving as resistive sensing element. A dual-matrix optimization approach consisting of a Threshold Mapping Matrix (TMM) and Energy Density Matrix (EDM) was used to determine optimized parameters without repeated trial-and-error. For localized thinning, sequential R-T scans with cooling intervals reduced redeposition from the Gaussian beam profile and produced uniform thickness reduction from 50 {\mu}m to 20--30 {\mu}m. The fabricated sensors were evaluated through thermal coefficient resistance (TCR) measurement, Infrared (IR) thermography, and airflow tests under steady and cyclic conditions controlled by artificial ventilation system. The fabricated devices showed a stable TCR of 3278 ppm {\deg}C$^{-1}$, a linear relationship calibration curve between velocity and resistance with $R^2$=0.986 and a 54% improvement in thermal response was achieved with the free-standing structure design compared to substrate-fixed designs. This fabrication approach removes the need for photolithography, wet/dry etching, and wafer bonding, enabling faster and lower-cost production of flexible, biocompatible flow sensors. The method can be applied to other MEMS devices that require compact size, flexibility, localized thinning and free-standing structures. - oai:arXiv.org:2512.08128v1 - physics.ins-det - Wed, 10 Dec 2025 00:00:00 -0500 + Ionic Disorder-Mediated Exfoliation and Optical Birefringence in a Non-van der Waals Oxide + https://arxiv.org/abs/2512.09248 + arXiv:2512.09248v1 Announce Type: new +Abstract: The landscape of two-dimensional photonics has been dominated by van der Waals (vdW) materials. Expanding this library to include non-vdW layered systems promises enhanced environmental robustness and access to novel functionalities, such as strong ionic conductivity, yet their exfoliation remains challenging. Here, we establish Na2Zn2TeO6 (NZTO), a P2-type superionic conductor, as an exfoliable non-vdW optical material. We demonstrate that the highly disordered, mobile Na+ interlayer inherently facilitates mechanical cleavage down to few-nanometer thicknesses (about 4 nm). Optical interrogation via spectroscopic ellipsometry reveals NZTO as a wide-bandgap dielectric with pronounced optical birefringence (Delta_n about 0.25) across the visible and near-infrared spectrum. The lattice dynamics, probed by temperature-resolved Raman spectroscopy, underscore the rigidity of the [Zn2TeO6]2- framework, which remains largely decoupled from the high ionic mobility. These results identify NZTO as a compelling platform for robust, anisotropic dielectric photonics, simultaneously opening a pathway toward the convergence of ionic transport and optical control - an emerging paradigm we term iono-photonics. + oai:arXiv.org:2512.09248v1 + physics.optics + cond-mat.mtrl-sci + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Mohammad Nizar Mohamed Zukri, Muhammad Salman Al Farisi, Yoshihiro Hasegawa, Mitsuhiro Shikida + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + N. V. Pak, M. K. Tatmyshevskiy, I. A. Kruglov, K. V. Kravtsov, A. A. Minnekhanov, D. V. Grudinin, A. N. Toksumakov, A. S. Slavich, D. I. Yakubovsky, A. A. Vyshnevyy, M. A. El-Sayed, G. A. Ermolaev, A. V. Arsenin, V. S. Volkov - Laser-assisted deposition of carbon nanotubes in optical fibers with multiparameter control - https://arxiv.org/abs/2512.08154 - arXiv:2512.08154v1 Announce Type: new -Abstract: We demonstrate a new method to deposit carbon nanotubes (CNT) on optical fibers based on a syringe-loaded CNT solution axially aligned to the fiber tip. A laser generates an optical tweezer in a water-based CNT solution, depositing nanotubes over the fiber cross-section. The parameters are adjusted, resulting in two deposited CNT layers with distinct thicknesses. This setup employs smaller solution volumes than those commonly used in beckers, providing high confinement, protection, and interaction of nanotubes, laser, and fiber, offering a promising alternative for real-time monitoring, which are significant to the development of industrial fiber lasers and biomedical optoacoustic devices. - oai:arXiv.org:2512.08154v1 + Scalable van der Waals Photonics: High-Refractive-Index Gallium Sulfide Films with Single-Crystal Optical Properties + https://arxiv.org/abs/2512.09255 + arXiv:2512.09255v1 Announce Type: new +Abstract: The integration of high-refractive-index dielectrics into scalable photonic architectures is foundational to advancing integrated circuits and augmented reality (AR) displays. Van der Waals (vdW) materials offer exceptional optical properties, including high refractive indices and giant anisotropy, but their implementation is constrained by the small area and uncontrolled thickness of mechanically exfoliated flakes. Here, we demonstrate that atomic layer deposition (ALD) grown gallium sulfide (GaS) overcomes the trade-off between high optical performance and manufacturability, emerging as a large-scale vdW dielectric platform. Through rigorous optical and structural benchmarking against pristine single crystals, we establish that the optical constants (n, k) of ALD-GaS are virtually indistinguishable from single-crystal counterparts. By leveraging the retained out-of-plane anisotropy, we demonstrate that ALD-GaS enables superior suppression of crosstalk in densely integrated waveguides compared to conventional scalable high-index platforms. Our findings establish ALD-GaS as a technologically viable pathway for implementing anisotropic vdW materials in visible-spectrum photonics. + oai:arXiv.org:2512.09255v1 physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + cond-mat.mtrl-sci + physics.app-ph + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - 10.1109/SBFotonIOPC66433.2025.11218439 - R. E. da Silva and C. M. B. Cordeiro, "Laser-Assisted Deposition of Carbon Nanotubes in Optical Fibers with Multiparameter Control," SBFoton International Optics and Photonics Conference, Sao Pedro SP, Brazil, 2025, pp. 1-3 - Ricardo E. da Silva, Cristiano M. B. Cordeiro + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Aleksandr Slavich, Georgy Ermolaev, Dmitriy Grudinin, Mikhail Tatmyshevskiy, Alexander Syuy, Nikolay Pak, Dmitry Yakubovsky, Mikhail Mironov, Adilet Toksumakov, Alexander Melentev, Elena Zhukova, Anton Minnekhanov, Gleb Tselikov, Ivan Kruglov, Sergey M. Novikov, Andrey Vyshnevyy, Aleksey Arsenin, Valentyn Volkov - Seasonal thermal stress analysis of defective mass concrete sidewalls based on the average forming temperature method - https://arxiv.org/abs/2512.08158 - arXiv:2512.08158v1 Announce Type: new -Abstract: Thermal cracking in urban underground sidewalls is frequently observed when structures are cast in summer and enter service in winter, as seasonal temperature gradients act under structural restraint. To quantify the local stress field associated with pre-existing cracks, an orthogonal finite-element simulation matrix of 16 combinations is constructed. Distributions of maximum principal stress () at the surface crack tip and along the upper half of the crack bottom are evaluated using steady-state thermal loading and a linear-elastic constitutive model. Across all cases, pronounced tensile stress concentration occurs at both locations: the maximum ranges from 19.2 to 34.1 MPa at the crack surface end and from 17.2 to 29.4 MPa at the crack bottom. These concentrated values are consistently higher than the stress level at the same locations in an otherwise identical uncracked wall, clarifying how seasonal temperature gradients under restraint amplify local stresses around existing defects. The quantitative ranges reported here provide a basis for risk screening and for formulating practical mitigation measures (e.g., joint spacing and insulation strategies) in the design and operation of urban underground enclosure walls. In addition, three-dimensional simulations of randomly distributed internal voids show that adopting average forming temperature increases the peak tensile stress on void surfaces from 3.42 to 4.40 MPa at 10 deg C and from 5.98 to 6.96 MPa at -5 deg C, further highlighting the risk amplification effect of AFT under cold service conditions. - oai:arXiv.org:2512.08158v1 - physics.comp-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Generation of Polarization-Tunable Hybrid Cylindrical Vector gamma Rays + https://arxiv.org/abs/2512.09268 + arXiv:2512.09268v1 Announce Type: new +Abstract: Cylindrical vector (CV) gamma rays can introduce spatially structured polarization as a new degree of freedom for fundamental research and practical applications. However, their generation and control remain largely unexplored. Here, we put forward a novel method to generate CV gamma rays with tunable hybrid polarization via a rotating electron beam interacting with a solid foil. In this process, the beam generates a coherent transition radiation field and subsequently emits gamma rays through nonlinear Compton scattering. By manipulating the initial azimuthal momentum of the beam, the polarization angle of gamma rays relative to the transverse momentum can be controlled, yielding tunable hybrid CV polarization states. Three-dimensional spin-resolved particle-in-cell simulations demonstrate continuous tuning of the polarization angle across (-90{\deg}, 90{\deg}) with a high polarization degree exceeding 60%. Our work contributes to the development of structured gamma rays, potentially opening new avenues in high-energy physics, nuclear science, and laboratory astrophysics. + oai:arXiv.org:2512.09268v1 + physics.plasm-ph + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Ziyan Zhao, Ting Peng, Peng Wu, Chaojun Hu, Qilin Yi, Chuangrui Huang, Junjie Niu, Xiaoxue Xu, Tao Li, Yuan Li + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Si-Man Liu, Yue Cao, Kun Xue, Li-Xiang Hu, Xin-Yu Liu, Xin-Yan Li, Chao-Zhi Li, Xin-Rong Xu, Ke Liu, Wei-Quan Wang, De-Bin Zou, Yan Yin, Jian-Xing Li, Tong-Pu Yu - Efficient simulation framework for modeling collective emission in ensembles of inhomogeneous solid-state emitters - https://arxiv.org/abs/2512.08174 - arXiv:2512.08174v1 Announce Type: new -Abstract: An efficient simulation framework is proposed to model collective emission in disordered ensembles of quantum emitters. Using a cumulant expansion approach, the computational complexity scales polynomially as opposed to exponentially with the number of emitters, enabling Monte Carlo sampling over a large number of realizations. The framework is applied to model negatively charged silicon-vacancy (SiV$^{-}$) centers inside diamond. Incorporating spatial disorder and inhomogeneous broadening, we obtain statistically averaged responses over hundreds of SiV$^{-}$ clusters. These simulations reveal two signatures of collective behavior. First, dynamics of fully inverted clusters show that superradiant emission occurs only with sufficiently large emitter number and high quantum efficiency. Unlike ideal Dicke superradiance, the burst is substantially suppressed by strong near-field dipole-dipole interaction, consistent with existing theoretical predictions. Second, under continuous-wave excitation we compute photoluminescence-excitation spectra, which exhibit interaction-induced broadening in the distribution of resonance peaks. The corresponding density of states also displays a non-zero skewness. Overall, by incorporating realistic inhomogeneities in emitter clusters, our framework is able to predict statistics for disordered ensembles that can be compared to experiments directly. Our approach generalizes to other types of emitters, including atoms, molecules, and quantum dots, thus providing a practical tool for analyzing collective behavior in realistic quantum systems. - oai:arXiv.org:2512.08174v1 - physics.optics + Beta-Ga2O3 Sub-Micron FinFETs with Si Delta-Doped Channel Modulating Charge Density Above 3x10^13 cm^-2 + https://arxiv.org/abs/2512.09279 + arXiv:2512.09279v1 Announce Type: new +Abstract: This letter reports on the design and demonstration of high-performance Beta-Ga2O3 FinFETs utilizing MOCVD-grown Si delta-doped channels to achieve enhanced carrier transport and electrostatic control. A record high sheet charge density of 3.3x10^13 cm^-2 was modulated using 100 nm fin channels, delivering a peak drain current of 410 mA/mm and a peak transconductance of 60 mS/mm. The FinFET architecture enables strong gate modulation, achieving a high Ion/Ioff ratio between 10^8 and 10^9. A low contact resistance of 0.42 ohm.mm was achieved to the Si delta-doped channel using MOCVD contact regrowth. Small-signal RF characterization revealed a current-gain cutoff frequency (fT) of 3.8 GHz and a maximum oscillation frequency (fMAX) of 2.1 GHz for a 0.8-micrometer gate length. These results demonstrate the efficacy of combining precision delta-doping with a 3D FinFET geometry for high-frequency Beta-Ga2O3 electronics, establishing a platform for future RF and high-power applications + oai:arXiv.org:2512.09279v1 physics.app-ph - physics.comp-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Qingyi Zhou, Wenxin Wu, Maryam Zahedian, Zongfu Yu, Jennifer T. Choy + http://creativecommons.org/licenses/by/4.0/ + Nabasindhu Das, Cameron Gorsak, Ankita Kashyap, Advait Gilankar, Pushpanshu Tripathi, Salil A Paranjape, Trevor Thornton, Hari Nair, Nidhin Kurian Kalarickal - Restoring Network Evolution from Static Structure - https://arxiv.org/abs/2512.08209 - arXiv:2512.08209v1 Announce Type: new -Abstract: The dynamical evolution of complex networks underpins the structure-function relationships in natural and artificial systems. Yet, restoring a network's formation from a single static snapshot remains challenging. Here, we present a transferable machine learning framework that infers network evolutionary trajectories solely from present topology. By integrating graph neural networks with transformers, our approach unlocks a latent temporal dimension directly from the static topology. Evaluated across diverse domains, the framework achieves high transfer accuracy of up to 95.3%, demonstrating its robustness and transferability. Applied to the Drosophila brain connectome, it restores the formation times of over 2.6 million neural connections, revealing that early-forming links support essential behaviors such as mating and foraging, whereas later-forming connections underpin complex sensory and social functions. These results demonstrate that a substantial fraction of evolutionary information is encoded within static network architecture, offering a powerful, general tool for elucidating the hidden temporal dynamics of complex systems. - oai:arXiv.org:2512.08209v1 - physics.soc-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Real-Time-Capable Betatron Tune Measurement from Schottky Spectra Using Deep Learning and Uncertainty-Aware Kalman Filtering + https://arxiv.org/abs/2512.09302 + arXiv:2512.09302v1 Announce Type: new +Abstract: Betatron tune measurement is essential for beam control in compact proton-therapy synchrotrons, yet conventional peak-detection techniques are not robust under the low signal-to-noise ratio (SNR) conditions typical of these machines. This work presents a lightweight convolutional neural network that performs real-time tune extraction from Schottky spectra with sub-millisecond inference latency and calibrated uncertainty estimates. The model uses attention-based pooling for reliable peak localization and a dual-branch architecture that jointly predicts the tune and its associated uncertainty. Trained with a Laplace negative log-likelihood loss, it produces uncertainty estimates whose magnitude tracks the instantaneous prediction error, which enables uncertainty-aware Kalman filtering for temporal smoothing. Experiments on a large synthetic dataset spanning SNR levels from 0 to $-20$\,dB demonstrate substantial performance gains over traditional peak-detection baselines, while the Kalman filter further suppresses transient outliers in time-series operation. Preliminary validation on operational beam data confirms stable tune tracking without retraining. With only about $2.0\times 10^{4}$ trainable parameters and real-time inference on commodity GPU hardware, the proposed diagnostic offers a practical solution for rapid and accurate betatron tune monitoring in compact medical synchrotrons and similar accelerators. + oai:arXiv.org:2512.09302v1 + physics.acc-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Jiu Zhang, Zhanwei Du, Hongwei Hu, Ke Wu, Tongchao Li, Chuan Shi, Xiaohui Huang, Yamir Moreno, Yanqing Hu + Peihan Sun, Manzhou Zhang, Renxian Yuan, Deming Li, Jian Dong, Ying Shi - Frequency Locking to Environmental Forcing Suppresses Oscillatory Extinction in Phage-Bacteria Interactions - https://arxiv.org/abs/2512.08224 - arXiv:2512.08224v1 Announce Type: new -Abstract: Bacteriophage-bacteria interactions are central to microbial ecology, influencing evolution, biogeochemical cycles, and pathogen behavior. Most theoretical models assume static environments and passive bacterial hosts, neglecting the joint effects of bacterial traits and environmental fluctuations on coexistence dynamics. This limitation hinders the prediction of microbial persistence in dynamic ecosystems such as soils and oceans.Using a minimal ordinary differential equation framework, we show that the bacterial growth rate and the phage adsorption rate collectively determine three possible ecological outcomes: phage extinction, stable coexistence, or oscillation-induced extinction. Specifically, we demonstrate that environmental fluctuations can suppress destructive oscillations through resonance, promoting coexistence where static models otherwise predict collapse. Counterintuitively, we find that lower bacterial growth rates are helpful in enhancing survival under high infection pressure, elucidating the observed post-infection growth reduction.Our studies reframe bacterial hosts as active builders of ecological dynamics and environmental variation as a potential stabilizing force. Our findings thus bridge a key theory-experiment gap and provide a foundational framework for predicting microbial responses to environmental stress, which might have potential implications for phage therapy, microbiome management, and climate-impacted community resilience. - oai:arXiv.org:2512.08224v1 - physics.bio-ph - nlin.CD - q-bio.PE - Wed, 10 Dec 2025 00:00:00 -0500 + Functional Percolation: A Perspective on Criticality of Form and Function + https://arxiv.org/abs/2512.09317 + arXiv:2512.09317v1 Announce Type: new +Abstract: Understanding the physical constraints and minimal conditions that enable information processing in extended systems remains a central challenge across disciplines, from neuroscience and artificial intelligence to social and physical networks. Here we study how network connectivity both limits and enables information processing by analyzing random networks across the structural percolation transition. Using cascade-mediated dynamics as a minimal and universal mechanism for propagating state-dependent responses, we examine structural, functional, and information-theoretic observables as functions of mean degree in Erdos-Renyi networks. We find that the emergence of a giant connected component coincides with a sharp transition in realizable information processing: complex input-output response functions become accessible, functional diversity increases rapidly, output entropy rises, and directed information flow quantified by transfer entropy extends beyond local neighborhoods. These coincident transitions define a regime of functional percolation, referring to a sharp expansion of the space of realizable input-output functions at the structural percolation transition. Near criticality, networks exhibit a Pareto-optimal tradeoff between functional complexity and diversity, suggesting that percolation criticality provides a universal organizing principle for information processing in systems with local interactions and propagating influences. + oai:arXiv.org:2512.09317v1 + physics.soc-ph + cond-mat.stat-mech + cs.AI + physics.comp-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Hao-Neng Luo, Zhi-Xi Wu, Jian-Yue Guan + Galen J. Wilkerson - Ion-beam driven dust-cyclotron and dust-lower-hybrid instabilities in nonthermal dusty magnetoplasmas with dust-charge fluctuation - https://arxiv.org/abs/2512.08259 - arXiv:2512.08259v1 Announce Type: new -Abstract: We reveal a new dispersive dust-lower-hybrid (DLH)-like mode that can couple to modified dust-cyclotron (DC) waves in a dusty magnetoplasma by the influence of a streaming ion beam. Previous studies have overlooked such hybrid modes and the coupling in the study of resonant cyclotron instabilities in dusty magnetoplasmas. Using two-fluid models for positive ion beams and charged dust grains, nonthermal $\kappa$-density distributions for electrons and positive ions, and orbital motion limited (OML) models for dust-charge fluctuations, we derive a general linear dispersion relation for the coupled DLH and DC modes in the limit of when the hydrodynamic time scale is much longer than the dust-charging time scale. The hybrid mode propagates with a frequency lower than the typical dust-lower-hybrid frequency, $\widetilde{\omega}_{\rm{dl}}\equiv\omega_{\rm{pd}}\Omega_d/\sqrt{\omega^2_{\rm{pd}}+\Omega^2_d}$, where $\omega_{\rm{pd}}$ is the dust-plasma oscillation frequency and $\Omega_d$ is the dust-cyclotron frequency. We obtain the growth rates of instabilities due to Cerenkov and cyclotron interactions and analyze them, taking into account the influences of the static magnetic field, ion-to-electron temperature ratio, electron-to-dust number density ratio, dust-charge fluctuation, and superthermal electrons and ions. We find that the maximum growth rates tend to increase but reach steady states as the wave number increases. The instabilities reported here could be relevant to various plasma environments, including space plasmas (e.g., Earth's magnetosphere) and laboratory dusty plasma experiments. - oai:arXiv.org:2512.08259v1 + A Propagator-based Multi-level Monte Carlo Method for Kinetic Neutral Species in Edge Plasmas + https://arxiv.org/abs/2512.09334 + arXiv:2512.09334v1 Announce Type: new +Abstract: We propose and investigate a new multi-level Monte Carlo scheme for numerical solutions of the kinetic Boltzmann equation for neutral species in edge plasmas. In particular, this method explicitly exploits a key structural property of neutral particle dynamics: the prevalence of frequent collisions for which the outgoing velocity is determined by local plasma parameters. Using this property, we derive a multi-level algorithm based on collision event propagator and show, both analytically and through numerical experiments, that it reproduces the results of standard Monte Carlo methods. We further demonstrate that, in the context of coupled plasma-neutral edge simulations employing correlated Monte Carlo, the proposed scheme retains trajectory correlation to machine precision as the system evolves, whereas conventional methods exhibit rapid decorrelation. These results indicate that the propagator-based multi-level Monte Carlo scheme is a promising candidate for use in fully implicit Jacobian-free Newton-Krylov (JFNK) solvers for coupled plasma-neutral systems. + oai:arXiv.org:2512.09334v1 physics.plasm-ph - Wed, 10 Dec 2025 00:00:00 -0500 + cs.NA + math.NA + physics.comp-ph + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - 10.1088/1402-4896/ae296d - A. P. Misra, N. P. Acharya, S. Basnet, R. Khanal + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Gregory J. Parker, Maxim V. Umansky, Benjamin D. Dudson - Self-Reinforced Deep Priors for Reparameterized Full Waveform Inversion - https://arxiv.org/abs/2512.08284 - arXiv:2512.08284v1 Announce Type: new -Abstract: Full waveform inversion (FWI) has become a widely adopted technique for high-resolution subsurface imaging. However, its inherent strong nonlinearity often results in convergence toward local minima. Recently, deep image prior-based reparameterized FWI (DIP-FWI) has been proposed to alleviate the dependence on massive training data. By exploiting the spectral bias and implicit regularization in the neural network architecture, DIP-FWI can effectively avoid local minima and reconstruct more geologically plausible velocity models. Nevertheless, existing DIP-FWI typically use a fixed random input throughout the inversion process, which fails to utilize the mapping and correlation between the input and output of the network. Moreover, under complex geological conditions, the lack of informative prior in the input can exacerbate the ill-posedness of the inverse problem, leading to artifacts and unstable reconstructions. To address these limitations, we propose a self-reinforced DIP-FWI (SRDIP-FWI) framework, in which a steering algorithm alternately updates both the network parameters and the input at each iteration using feedback from the current network output. This design allows adaptive structural enhancement and improved regularization, thereby effectively mitigating the ill-posedness in FWI. Additionally, we analyze the spectral bias of the network in SRDIP-FWI and quantify its role in multiscale velocity model building. Synthetic tests and field land data application demonstrate that SRDIP-FWI achieves superior resolution, improved accuracy and greater depth penetration compared to multiscale FWI. More importantly, SRDIP-FWI eliminates the need for manual frequency-band selection and time-window picking, substantially simplifying the inversion workflow. Overall, the proposed method provides a novel, adaptive and robust framework for accurate subsurface velocity model reconstruction. - oai:arXiv.org:2512.08284v1 - physics.geo-ph - cs.CV - Wed, 10 Dec 2025 00:00:00 -0500 + Sound emission from oscillating bubbles trapped by the collapse of drop-impact craters + https://arxiv.org/abs/2512.09336 + arXiv:2512.09336v1 Announce Type: new +Abstract: When a drop impacts a deep pool, it forms a crater which subsequently rebounds. Under certain conditions, a dimple forms at the crater bottom, which pinches off to entrap a small bubble. The oscillation of this entrapped bubble is the primary source of the underwater sound produced by rain. We use simultaneous ultra-high-speed video imaging and synchronized acoustic recording, with an immersed hydrophone, to investigate the details of the sound formation, over a range of impact Weber numbers and different dimple shapes. With frame-rates as high as 5 million fps, we can track the shape evolution of the pinched off dimple-bubble, which experiences large volumetric compression, by as much as 50%. The subsequent volume oscillations are consistent with the observed $\simeq 125$ Pa acoustic pressure amplitude, for the strongest compression. For our configuration the sound amplitude increases for smaller bubbles pinched off from the dimple. The acoustic forcing mechanism is therefore the inertial focusing of the momentum of the liquid outside the dimple, as it pinches off. The acoustic frequency agrees well with the Minnaert theory for freely oscillating spherical bubbles, of the same size. The finer details of the acoustic signal reveal an interplay between the larger dimple bubble and the tiny bubble entrapped during the initial contact between the drop and pool. For the singular dimple where no bubble is pinched off, the sound generation has a broader range of frequencies, with the tiny bubble oscillating at $\sim 100$ kHz, after being deformed by the rapid vertical retraction of the dimple below the singular jet. + oai:arXiv.org:2512.09336v1 + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Guangyuan Zou, Junlun Li, Feng Liu, Xuejing Zheng, Jianjian Xie, Guoyi Chen + http://creativecommons.org/licenses/by-nc-sa/4.0/ + Zi Qiang Yang, Yuan Si Tian, Er Qiang Li, Sigur{\dh}ur Tryggvi Thoroddsen - Rigid body kinematics in an intuitive group-theoretic approach, as completely as possible: Part I Rotational phenomena - https://arxiv.org/abs/2512.08285 - arXiv:2512.08285v1 Announce Type: new -Abstract: This paper focuses on rotational phenomena of rigid body kinematics. It discusses them in a group-theoretic approach as completely as possible, using methods and notations as intuitive as possible. With a review of current literature, this article also covers some original parts that remain largely unexplored. - oai:arXiv.org:2512.08285v1 - physics.class-ph - Wed, 10 Dec 2025 00:00:00 -0500 + 389.3-Tb/s 1017-km C-band Transmission over Field-Installed 12-Coupled-Core Fiber Cable with >12-Tb/s Spatial MIMO Channels + https://arxiv.org/abs/2512.09344 + arXiv:2512.09344v1 Announce Type: new +Abstract: We demonstrate 4.65-THz WDM/SDM transmission of 140-Gbaud PS-QAM signals over field-installed 12-coupled-core fiber cable with standard cladding diameter, achieving a record 0.455 Pb/s coupled-core capacity in a field environment. We also demonstrate 0.389 Pb/s over-1000-km transmission of spatial MIMO channels with >12 Tb/s/wavelength net bitrate. + oai:arXiv.org:2512.09344v1 + physics.optics + eess.SP + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Ziyuan Wang + http://creativecommons.org/licenses/by/4.0/ + Akira Kawai, Kohki Shibahara, Megumi Hoshi, Masanori Nakamura, Takayuki Kobayashi, Ryota Imada, Takayoshi Mori, Taiji Sakamoto, Yusuke Yamada, Kazuhide Nakajima, Munehiko Nagatani, Hitoshi Wakita, Yuta Shiratori, Hiroshi Yamazaki, Hiroyuki Takahashi, Soichi Endo, Takemi Hasegawa, Ryo Nagase, Yutaka Miyamoto - Photon Phase-Space Dynamics in a Plasma Wakefield Accelerator - https://arxiv.org/abs/2512.08295 - arXiv:2512.08295v1 Announce Type: new -Abstract: Frequency up-shifting of laser light in a beam-driven plasma wakefield has the potential to provide high-intensity sources of short wavelength radiation. Simulations have demonstrated that a laser pulse can undergo large frequency shifts, limited only by the drive beam energy, when the plasma density is tailored to match the accelerating phase of the wake to the group velocity of the pulse. Here, we study the dynamical evolution of photons in the phase-space vicinity of the plasma wake- phase matching condition. Numerical calculations using a photon kinetic model are validated by direct comparison with full electromagnetic particle-in-cell simulations. These calculations form the basis of a linear theory of the photon dynamics which reveals several important results, including scalings for the properties of the witness pulse and a self-similar solution for the photon phase-space dynamics. One prediction of the theory is that the pulse can be compressed indefinitely with no lower bound on the duration. This predication suggests that photon acceleration can provide a novel source of sub-femtosecond, short wavelength radiation. - oai:arXiv.org:2512.08295v1 - physics.plasm-ph - math-ph - math.MP + 133-Tbps 1040-km (13$\times$80 km) Lumped-Amplified Transmission Over 22 THz in S-to-U-Band Using Hybrid Multiband Repeater with PPLN-Based Optical Parametric Amplifiers and EDFAs + https://arxiv.org/abs/2512.09347 + arXiv:2512.09347v1 Announce Type: new +Abstract: We demonstrated 22.05-THz four-band long-haul transmission with a S-to-U-band lumped repeater consisting of PPLN-based optical parametric amplifiers and EDFAs over an 80-km-span SMF link. The achieved net bitrate was 133.06 Tbps at 1040 km with the 25.5-dBm fibre launch power designed by accounting for ISRS. + oai:arXiv.org:2512.09347v1 physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + eess.SP + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Neil Beri, John Palastro, Qian Qian, Kyle Miller, Brandon Russell, Alexander Thomas + Shimpei Shimizu, Takayuki Kobayashi, Masashi Abe, Takushi Kazama, Akira Kawai, Kosuke Kimura, Masanori Nakamura, Fukutaro Hamaoka, Koji Enbutsu, Takahiro Kashiwazaki, Munehiko Nagatani, Hitoshi Wakita, Yuta Shiratori, Hiroshi Yamazaki, Hiroyuki Takahashi, Takeshi Umeki, Yutaka Miyamoto - Optics experiments as a tool for developing critical thinking in physics education - https://arxiv.org/abs/2512.08297 - arXiv:2512.08297v1 Announce Type: new -Abstract: Experimental activities are an essential part of physics education. In addition to conveying scientific knowledge, they play a significant role in developing scientific literacy, inquiry skills, and critical thinking. In today's world, where students are exposed to vast amounts of information of varying quality, the ability to analyse, evaluate, and interpret information correctly has become increasingly important. This paper presents a series of physics experiments in the field of optics, specifically designed to foster critical thinking at various stages of the inquiry process. The topic of optics was chosen deliberately, as many optical phenomena occur naturally in everyday life, are familiar to students, and stimulate their curiosity. At the same time, they provide space for formulating hypotheses, designing experiments, interpreting data, and evaluating alternative explanations. Each experiment begins with a real-life problem situation that students are expected to explore and resolve through their own investigative work. The tasks are structured to encourage discussion, require argumentation, and promote reflection on both the process and the outcomes. The proposed experiments are suitable for students at both primary and secondary school levels and can be implemented in formal as well as non-formal educational settings. The aim of this contribution is to demonstrate how well-designed and pedagogically grounded experiments can not only enhance the understanding of physical concepts but also systematically develop critical thinking skills - one of the key competencies of 21st-century education. - oai:arXiv.org:2512.08297v1 - physics.ed-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Thin-film magnomechanics in the low gigahertz regime + https://arxiv.org/abs/2512.09348 + arXiv:2512.09348v1 Announce Type: new +Abstract: The coherent interaction between magnons and phonons in the low-GHz regime represents an unexplored frontier in hybrid magnonics, critical for quantum information processing and microwave-to-acoustic transduction. While previous studies have focused on higher frequencies (>5 GHz), we demonstrate magnon-phonon coupling near 2 GHz using spoof surface plasmon polariton (SSPP) waveguides integrated with yttrium iron garnet (YIG) thin films of varying thicknesses. SSPP waveguides provide strong slow-wave enhancement, enabling efficient magnon readout in this challenging regime. Systematic measurements reveal the dependence of coupling strength on YIG thickness and phonon wavelength matching, achieving cooperativity C = 1 for a 3 $\mu$m film at 2 GHz. Angle-dependent studies uncover coupling to both transverse and longitudinal phonon modes. Further investigation shows that thicker films exhibit rich multimode dynamics between high-order magnons and HBAR phonons. These results establish a robust low-GHz magnomechanical platform, opening pathways for multimode quantum transduction and hardware-efficient quantum technologies. + oai:arXiv.org:2512.09348v1 + physics.app-ph + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - 10.1088/1742-6596/3155/1/012017 - J. Phys.: Conf. Ser. 3155 012017 (2025) - Miriam Spodniakov\'a Pfefferov\'a, Martin Plesch + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Yu Jiang, Zixin Yan, Yizhong Huang, Xufeng Zhang - Critical Thresholds in Non-Pharmaceutical Interventions for Epidemic Control - https://arxiv.org/abs/2512.08339 - arXiv:2512.08339v1 Announce Type: new -Abstract: Non-pharmaceutical interventions, such as contact tracing and social distancing, are critical for controlling epidemic outbreaks, yet their dynamic interactions remain underexplored. We introduce a probabilistic framework to analyze the synergy between contact tracing speed, quantified by the contact tracing period $\tau$, and the average number of close contacts, $\bar{k}_+$, reflecting social distancing measures. We identify critical thresholds ($R=1$) that separate pandemic and contained phases in the $\bar{k}_{+}-\tau$ plane, validated using high-resolution data from Shenzhen's 2022 Omicron outbreak (1,187 cases, 86,451 contacts). Our findings show that contact tracing alone can contain diseases with $R_0 < 2.12$ (95% CI 2.07-2.16), covering 43.33% of major infectious diseases, while combining with social distancing extends control to $R_0 < 7.82$ (95% CI 7.70-7.93), encompassing 86.67% of pathogens. These results, supported by empirical data, highlight the efficacy of rapid tracing and targeted social distancing as alternatives to mass PCR testing. Our framework offers actionable insights for optimizing NPI strategies, though challenges in scaling to regions with higher tracing miss rates or weaker infrastructure underscore the need for adaptive, data-driven policies. - oai:arXiv.org:2512.08339v1 + Phase transition to causal symmetry reveals operational autonomy in sociotechnical systems + https://arxiv.org/abs/2512.09352 + arXiv:2512.09352v1 Announce Type: new +Abstract: Complex adaptive systems persist through continuous transformation, yet the dynamical principles governing their long-term stability remain poorly characterized. Here we analyze 50 large-scale collaborative ecosystems spanning 11,042 system-months to quantify the emergence of operational autonomy. We develop an order parameter (Gamma) measuring structural persistence amid component turnover and characterize directional coupling between organizational architecture and collective activity. Gamma exhibits a bimodal distribution (Hartigan p=0.0126; Delta BIC = 2,000), identifying two regimes: an exploratory phase of high variance and a mature phase with 1.77x variance collapse. Granger analysis reveals causal symmetrization at maturity - the structure-activity coupling ratio shifts from 0.71 (activity-driven) to 0.94 (bidirectional), indicating that architecture increasingly constrains collective coordination. + A viability index, combining activity and structure, outperforms activity-based prediction (AUC = 0.88 vs 0.81), identifying 'zombie' systems where high churn masks structural decay. This extends recent work by Ait et al., who identified 'zombie' projects exhibiting activity without development based on non-coding contributions. Our metric identifies structural zombies: projects where coding activity persists but fails to preserve architectural invariants. + These results establish causal symmetrization as an empirically validated signature of self-organizing autonomy applicable across complex collaborative systems - a dynamical regime previously theorized in biological contexts but here demonstrated and measured in artificial ones. + oai:arXiv.org:2512.09352v1 physics.soc-ph - Wed, 10 Dec 2025 00:00:00 -0500 + cs.CY + cs.SE + Thu, 11 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Jinghui Wang, Yutian Zeng, Cong Xu, Xiyun Zhang, Zhanwei Du, Jiarong Xie, Jiu Zhang, Sen Pei, Zijian Feng, Yanqing Hu + Anthony Gosme - Enzyme-driven phase separation - https://arxiv.org/abs/2512.08356 - arXiv:2512.08356v1 Announce Type: new -Abstract: The formation of polarized signaling domains on cell membranes is a fundamental example of biological pattern formation. While such patterns resemble structures from equilibrium phase separation, they are intrinsically non-equilibrium, driven by energy-consuming enzymatic cycles that switch molecules like phosphoinositides or small GTPases between distinct states. Here, we develop a minimal model of this enzyme-driven phase ordering process. Starting from microscopic reaction kinetics, we derive a mesoscopic theory that belongs to the class of active Model A with a global constraint. This framework yields an explicit mean-field phase diagram and closed-form expressions for key observables, such as interfacial tension, domain fractions, and phase coexistence boundaries, in terms of kinetic rates. In this context, phase coexistence is controlled by non-equilibrium parameters like catalytic rates and enzymatic asymmetry, rather than equilibrium parameters such as saturation concentrations. The resulting phase-separated domains rapidly exchange material with their surroundings. Their maintenance requires a continuous power input determined by enzymatic kinetics. The predicted phenomenology is consistent with experimental observations on reconstituted systems of phosphoinositide and Rab5 membrane patterning. We further study how metastable uniform states decay via nucleation of minority-phase domains and subsequent coarsening, driven by an effective interfacial tension. Using large deviation theory, we derive the critical nucleation radius under the action of the intrinsic, multiplicative chemical noise. The analytical results are quantitatively confirmed by stochastic simulations of the process. Our work provides a theoretical framework identifying key biochemical parameters controlling active phase separation on membrane scaffolds, offering testable predictions for experiments. - oai:arXiv.org:2512.08356v1 - physics.bio-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Twisted light from topological chiral exceptional points in a nanolaser array + https://arxiv.org/abs/2512.09388 + arXiv:2512.09388v1 Announce Type: new +Abstract: We propose and experimentally demonstrate an orbital angular momentum (OAM) nanolaser array arranged in a ring geometry on an InP-based photonic crystal membrane. The device realizes a non-Hermitian extension of the Rice-Mele model, featuring alternating coupling strengths and imaginary on-site detunings. This configuration supports a symmetry-protected zero mode stabilized by non-Hermitian particle-hole symmetry, which enforces a uniform $\pi/2$ phase shift between adjacent nanolasers, establishing a coherent phase winding around the array. By adjusting the gain/loss contrast in a parity-time (PT)-like pumping scheme, the system can be tuned to a chiral exceptional point, where energy flows unidirectionally between nanocavities despite their reciprocal coupling. This symmetry-enforced, directional tunneling leads to far-field emission carrying non-zero OAM, providing a direct signature of the phase-structured lasing mode. Our results demonstrate a robust and scalable strategy for engineering compact, phase-locked laser arrays with controllable angular momentum output, and open new avenues for structured light generation in integrated photonic platforms. + oai:arXiv.org:2512.09388v1 + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Damiano Andreghetti, Alfredo Braunstein, Luca Dall'Asta, Andrea Gamba + http://creativecommons.org/licenses/by/4.0/ + Kaiwen Ji, Melissa Hedir, Qi Zhong, Ramy El-Ganainy, Alejandro M. Yacomotti, Li Ge - Dielectric permittivity tensor dynamics of in-plane hyperbolic van der Waals MoOCl2 and emergent chiral photonic applications - https://arxiv.org/abs/2512.08383 - arXiv:2512.08383v1 Announce Type: new -Abstract: Van der Waals (vdW) crystals offer unique opportunities for modern nanophotonic applications owing to their intrinsic anisotropic nature. While most of them exhibit uniaxial anisotropy arising from weak out-of-plane vdW interaction, some of their representative families also exhibit an in-plane biaxial anisotropy. Among the latter, outstand vdW oxochlorides with in-plane axes of a different physical character (metallic or dielectric). Here, we present an accurate dynamics of dielectric permittivity tensor components of vdW MoOCl2 in the ultraviolet (UV) to visible (Vis) spectral region partly covering near-infrared (NIR). Addressing its enormously anisotropic optical constants, we focus on another hyperbolicity window of vdW MoOCl2 emerging in the UV spectral region that may potentially unlock rich light-matter interaction effects. Furthermore, we propose an approach towards designing nanoscale handedness preserved Vis light circular polarizers based on twisted helical vdW MoOCl2 heterostructures. Our findings display that vdW MoOCl2 provides a highly promising platform not only for hyperbolic, but also for chiral nanophotonic applications. - oai:arXiv.org:2512.08383v1 - physics.optics - cond-mat.mtrl-sci - Wed, 10 Dec 2025 00:00:00 -0500 + Stochastic Cooling Enhanced Steady-State Microbunching + https://arxiv.org/abs/2512.09399 + arXiv:2512.09399v1 Announce Type: new +Abstract: In this paper, we propose to combine two promising research topics in accelerator physics, i.e., optical stochastic cooling (OSC) and steady-state microbunching (SSMB). Our study shows that such an OSC-SSMB storage ring with a circumference of 50 m and beam energy of several hundred MeVs using present technology can deliver kilowatt radiation at 100 nm wavelength. A more ambitious application of OSC in an SSMB ring can push the radiation wavelength to an even shorter wavelength, such as EUV and soft X-ray. Such a powerful compact light source could benefit fundamental science research and industry applications. + oai:arXiv.org:2512.09399v1 + physics.acc-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Artsruni Margaryan, Maksim Sargsyan, Meri Hayrapetyan, David Karakhanyan, Kostya S. Novoselov, Davit A. Ghazaryan + Xiujie Deng - Development & first Performance evaluation of multielement monolithic HPGe detector for spectroscopy applications - https://arxiv.org/abs/2512.08389 - arXiv:2512.08389v1 Announce Type: new -Abstract: We present the first operational prototype of a high-purity Germanium (HPGe) detector developed within the framework of the European LEAPS-INNOV project. This prototype features a monolithic, multi-element sensor optimized for high-resolution X-ray spectroscopy in the hard X-ray regime. The study includes a comprehensive laboratory-based characterization of the detector's spectral and spatial performance, and an on-beam evaluation at the BM05 beamline of the ESRF synchrotron facility using monochromatic X-rays in the 20-50 keV energy range. Detailed characterization results are reported, including sensor performance metrics such as energy resolution, count rate, and spatial response uniformity. - oai:arXiv.org:2512.08389v1 - physics.ins-det - Wed, 10 Dec 2025 00:00:00 -0500 + Photophoretic Trapping: Fundamentals, Advances and Future Directions + https://arxiv.org/abs/2512.09401 + arXiv:2512.09401v1 Announce Type: new +Abstract: Photophoretic forces, several orders of magnitude stronger than radiation pressure, enable particle trapping at remarkably low optical intensities and have opened pathways to applications in aerosol science, free-space 3D volumetric displays, and even deployment of lightweight payloads in space. In this review, we provide a comprehensive explanation of the underlying physics of photophoretic forces and how they facilitate stable three-dimensional manipulation of absorbing particles. We examine the experimental configurations that enable robust trapping, and we detail the physical parameters that govern the magnitude and behavior of photophoretic forces in these geometries. The rich dynamical phenomena exhibited by photophoretically trapped particles are discussed alongside current and emerging applications and possible future research directions. This review thus attempts to systematically unify the theoretical, experimental, and application-oriented aspects of photophoretic trapping, with the aim of advancing and strengthening research in this rapidly developing field. + oai:arXiv.org:2512.09401v1 + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - N. Goyal, F. J. Iguaz, S. Aplin, A. Balerna, P. Bell, J. Casas, M. Cascella, S. Chatterji, C. Cohen, E. Collet, E. N. Gimenez, H. Graafsma, H. Hiresmann, K. Klementiev, T. Kolodziej, T. Martin, R. H. Menk, C. Menneglier, C. Meraihia, J. R. Murias, M. Porro, M. Quispe, B. Schmitt, S. Scully, M. Turcato, C. Ward, E. Welter + Anita Pahi, Kirty Ranjan Sahoo, Souvik Sil, Ayan Banerjee - A cold beam of BaOH molecules using a water-vapour seeded neon gas - https://arxiv.org/abs/2512.08402 - arXiv:2512.08402v1 Announce Type: new -Abstract: In this paper we report on the production and characterization of a cold beam of BaOH molecules using a cryogenic buffer-gas beam source. BaOH is a highly suitable molecule for studies of the violation of fundamental symmetries, such as the search for the electron's electric dipole moment. BaOH molecules are synthesised inside the cold source through laser ablation of a barium metal target while water vapor is seeded into the neon buffer gas. The BaOH flux is significantly enhanced ($\sim$11 times) when laser-exciting the barium atoms inside the buffer-gas cell on the $^1\mathrm S_0 - ^3\mathrm P_1$ transition. A similar enhancement has been reported for other alkaline-earth(-like) monohydroxides. For typical source conditions, the molecular beam has an average velocity of $\approx180$ m/s and an intensity of $\sim 10^{9}$ molecules s$^{-1}$ in $N=1$, which is comparable to that of cryogenic BaF beams. - oai:arXiv.org:2512.08402v1 - physics.atom-ph - Wed, 10 Dec 2025 00:00:00 -0500 + A power-in-bucket model enabled designs of nanostructure-enhanced waveguides for highly efficient wide-angle light couplings + https://arxiv.org/abs/2512.09405 + arXiv:2512.09405v1 Announce Type: new +Abstract: Well-designed nanostructures on fiber facets can boost wide-angle light coupling and thus gain considerable attention because of the potential for intensive applications. However, previous theories commonly concentrate on the configurations of the bare waveguide, lacking full consideration of structure-assisted couplings. Here, a power-in-bucket (PIB) model is introduced to explore the coupling behavior of structure-modified waveguides. The analytical model investigates two representative coupling scenarios,including Gaussian beam and plane wave excitation. The PIB-computed coefficient {\eta} enhancements agree well with the experimental values, especially for the multiple-mode fibers under large-angle illuminations. Using PIB to optimize the beam-fiber parameters, we show that at the incidence angle of 37 degree, {\eta} could increase from 0.3320 to 0.5102 by the identical ring gratings. Overall, the proposed model provides a useful account of the mechanism of grating-aided light couplings. These findings would be of great help in designing structure-enhanced probes for wide-angle broadband light collection applications. + oai:arXiv.org:2512.09405v1 + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Ties Hendrik Fikkers, Nithesh Balasubramanian, Joost W. F. van Hofslot, Maarten C. Mooij, Hendrick L. Bethlem, Steven Hoekstra + Wenbo Luo, Yitong Gu, Jianwei Wang, Fei Yu, Chunlei Yu, Lili Hu, Zhichao Ruan, Ning Wang - Dynamics of an internally actuated weakly elastic sphere in a general quadratic flow - https://arxiv.org/abs/2512.08408 - arXiv:2512.08408v1 Announce Type: new -Abstract: Internally actuated elastic particles are widely used in biomedical applications. It is imperative to understand the dynamics of such particles in pressure-driven microfluidic devices to manipulate their motion. We analytically examine the dynamics of an internally actuated elastic particle translating in a general unbounded quadratic flow in the inertialess limit. We consider the particle as a compressible weakly elastic sphere, and its motion is controlled by applying an external point force and a point torque at the centre of its undeformed shape. The fluid and the particle are modelled using the Stokes and the Navier elasticity equations, respectively. We use the domain perturbation method to capture the particle deformation. The point force and the point torque are obtained until \textit{O}($\alpha^2$), assuming $\alpha\ll 1$. Here, $\alpha$ is the measure of the particle elastic strain induced due to the fluid viscous stress. We present the results for the particle motion in a general unbounded quadratic flow. The results are simplified further for the motion along the centreline in the quadratic component of three Poiseuille flows: 1) elliptical Poiseuille, 2) plane Poiseuille, and 3) Hagen-Poiseuille flows. In the general quadratic flow, the point force at \textit{O}($\alpha$) is aligned with the particle velocity, while the force at \textit{O}($\alpha^2$) acts at an angle to the velocity. Furthermore, the torque is non-zero due to elastic effects at \textit{O}($\alpha$) and \textit{O}($\alpha^2$). For all the three Poiseuille flows, the point force until \textit{O}($\alpha^2$) is aligned with the particle velocity, while the torque comes as zero. - oai:arXiv.org:2512.08408v1 - physics.flu-dyn - Wed, 10 Dec 2025 00:00:00 -0500 + Coherent Tunneling by Adiabatic Passage in Silicon Nitride based Integrated Waveguide Structures + https://arxiv.org/abs/2512.09436 + arXiv:2512.09436v1 Announce Type: new +Abstract: Nowadays silicon nitride photonic integrated circuits serve as a mature platform for numerous applications. Planar waveguides and directional couplers made by CMOS-compatible technology are its basic elements. Here we demonstrate the possibilities of efficient light routing and transfer provided by the integrated planar Si3N4 waveguides structure based on the coherent tunneling by adiabatic passage (CTAP) at the 1.55um telecom band. We addressed both high- and low-confinement silicon nitride CTAP structures and proved high efficiency of light routing in them. The mechanisms that limit the light control efficiency have been revealed. The accessible parameters of such structures have been determined. Besides that, there was proposed the original hybrid Si3N4 Si - Si3N4 waveguides structure providing the enhanced efficiency and flexibility of the CTAP in comparison with the single-material Si3N4 waveguide structures. + oai:arXiv.org:2512.09436v1 + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Shashikant Verma, Navaneeth K. Marath + Olga Borovkova, Valery Lobanov, Junqiu Liu, Dmitry Chermoshentsev, Igor Bilenko - Trans-Arctic route feasibility on a pan-Arctic grid under bathymetric and sea-ice constraints - https://arxiv.org/abs/2512.08434 - arXiv:2512.08434v1 Announce Type: new -Abstract: Climate driven reductions in Arctic sea ice have renewed interest in trans Arctic shipping, but adoption remains limited by basic questions of route feasibility, safety and excess distance. Existing studies mostly compare idealised great circle shortcuts or use full weather routing systems, leaving a gap for simple basin scale diagnostics on realistic bathymetry and sea ice. We develop an offline graph based framework on a 0.5 degree pan Arctic grid that combines GEBCO 2024 bathymetry with a summer 2018 Arctic sea ice reanalysis from the Copernicus Marine Environment Monitoring Service (CMEMS). An A* pathfinding algorithm is applied to a canonical Europe Asia origin destination pair to quantify route availability and route length inflation relative to a great circle. Enforcing sea only feasibility increases route length by about 10 percent before depth and ice constraints are applied. Depth thresholds representative of under keel clearance (hmin = 20-50 m) remove up to roughly 15 percent of the sea mask but preserve a trans Arctic connection for hmin = 20 m. Summer sea ice exerts a strong seasonal control: continuous ice safe routes emerge only from mid August, with distances inflated by roughly 20-25 percent even in late summer. When depth and ice constraints are imposed jointly, only about 75 percent of sea cells remain safe and no continuous joint safe trans Arctic route exists in the tested season. The framework provides a basin scale screening tool for Arctic shipping and a baseline for forecast driven, multi objective routing studies. - oai:arXiv.org:2512.08434v1 - physics.geo-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Adaptive Punishment in Social Dilemmas + https://arxiv.org/abs/2512.09450 + arXiv:2512.09450v1 Announce Type: new +Abstract: We introduce a coevolutionary framework in which punishment intensity dynamically adapts to the fraction of cooperators in the population. Unlike static models, adaptive punishment reshapes the effective payoff landscape, driving transitions among canonical games, including the Prisoner's Dilemma, Harmony, Stag Hunt, and Chicken games. Analytical results reveal rich dynamical behaviors such as coexistence, bistability, limit cycle and Hopf bifurcation. These findings highlight adaptive punishment as a robust mechanism for sustaining cooperation by the coevolutionary feedback and offer insights into institutional design, ecological interactions, and social governance. + oai:arXiv.org:2512.09450v1 + physics.soc-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Abdella Mohamed, Xiangyu Hu + Xingfu Ke, Hao Yu, Xiao-Pu Han, Yi-Cheng Zhang, Fanyuan Meng - Scalable CFD Simulations in Multi-Billion Voxel Micro-CT Images of Porous Materials Using OpenFOAM on ARCHER2 - https://arxiv.org/abs/2512.08438 - arXiv:2512.08438v1 Announce Type: new -Abstract: This study investigates the use of High-Performance Computing (HPC) to simulate flow and transport in ultra-large micro-CT images of porous materials using Computational Fluid Dynamics (CFD). Two distinct rock samples, representative of two different rock formations - Bentheimer sandstone and Estaillades carbonate - are investigated. The Bentheimer sandstone image, with dimensions 1,950x1,950x10,800 voxels at 6 micron resolution, comprising 41 billion voxels, represents a largely homogeneous structure, while the Estaillades carbonate image, at 1,144x1,144x6,000 voxels and 3.9676 micron resolution, amounting to 8 billion voxels, features greater heterogeneity, including micro-porous regions. These images are used for direct CFD simulations with GeoChemFoam, our OpenFOAM-based numerical solver, leveraging the computational resources of the UK supercomputer ARCHER2. One of the key aspects of the study is the use of the Darcy-Brinkman-Stokes approach, for which the solid surface is represented using a volumetric indicator function, rather than a complex mesh. This enables the use of simple Cartesian meshes that can be generated in parallel in an efficient and scalable manner. The study explores both weak and strong scaling through subvolume decomposition, demonstrating that, due to the strong scalability and the computational power of ARCHER2, full-resolution CFD simulations can be carried out without the need for image size reduction. This work illustrates the potential of HPC to perform detailed, full-scale simulations on large, high-resolution micro-CT data. The approach relies on a meshing strategy that leverages simple, parallelisable Cartesian grids derived from volumetric indicator functions, eliminating the need for complex surface-conforming meshes and allowing scalable simulation of flow and transport in geological and engineering applications. - oai:arXiv.org:2512.08438v1 - physics.flu-dyn - Wed, 10 Dec 2025 00:00:00 -0500 + Dynamics of an impulse dielectric barrier discharge in pure ammonia gas using electrical characteristics and imaging analysis + https://arxiv.org/abs/2512.09454 + arXiv:2512.09454v1 Announce Type: new +Abstract: A glow nanosecond discharge from a plane-to-plane impulse dielectric barrier discharge (iDBD) with ammonia gas has been characterised by employing fast imaging and electrical diagnostics. More precisely, the aim of this study is to investigate the dynamics of the discharge establishment under various conditions of applied voltage, pressure, and gas gap. The comparison between the current measurements and the image analysis exposes a strong correlation between the fast excitation and ionization wave velocity and the rising current velocity. This correlation has been found only for diffuse mode discharge since a front wave could be clearly defined, denoted as the luminous propagation front (LPF). Furthermore, this correlation is supported by a proportionality factor of 1.5 10$^{-3}$ which is systematic over the studied conditions. Further investigations are considered to evaluate the relevance of such a value over more parameters. + oai:arXiv.org:2512.09454v1 + physics.plasm-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - J. Maes, Gavin J. Pringle, Hannah P. Menke - - - Transition in elastic Dean flow: the centre-mode versus hoop-stress pathways - https://arxiv.org/abs/2512.08456 - arXiv:2512.08456v1 Announce Type: new -Abstract: We analyse the stability of viscoelastic Dean flow (flow of an elastic fluid through a curved two-dimensional channel, driven by an azimuthal pressure gradient) in the absence of fluid inertia. This configuration is well known to exhibit a hoop-stress-driven `purely elastic' instability (referred to henceforth as the hoop-stress mode -- `HSM') on account of the base-flow streamline curvature. The objective of this study is to demonstrate the existence and importance of a distinct elastic instability in this flow configuration, which is not driven by hoop-stresses, but instead is a continuation of a novel `centre-mode' (CM) instability recently identified in rectilinear shear flows. We use both the Oldroyd-B and FENE-P models to map out parameter regimes in the $W\!i$--$\epsilon$--$\beta$ space where the aforementioned instabilities are present. Here, $W\!i$ is a suitably defined Weissenberg number that characterizes fluid elasticity, $\beta$ is the ratio of solvent to total solution viscosity, and $\epsilon$ is the ratio of the gap (channel) width to the radius of curvature. For FENE-P model, decreasing the finite extensibility parameter $L$ has opposing effects on the HSM and CM instabilities -- stabilising the former, but destabilising the latter. In the dilute solution regime ($\beta > 0.95$), and for realistic values of $L \sim O(100)$, corresponding to polymer molecular weights of $O(10^{5-6})$g/mol, the CM remains the most unstable mode for $\epsilon \leq 0.25$, rendering it potentially relevant to the onset of elastic turbulence in the flow of such polymer solutions through curved channels. - oai:arXiv.org:2512.08456v1 - physics.flu-dyn - cond-mat.soft - Wed, 10 Dec 2025 00:00:00 -0500 - new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - P. S. D. Surya Phani Tej, Ganesh Subramanian, V. Shankar + Ronny Jean-Marie-Desiree, Aymane Najah, Ludovic De Poucques, Stephane Cuynet - Angular emission of scintillators for nuclear fusion diagnostics - https://arxiv.org/abs/2512.08501 - arXiv:2512.08501v1 Announce Type: new -Abstract: Accurate characterization of fast-ion behavior is essential for the safe and efficient operation of nuclear fusion plasmas, as energetic particle losses can degrade plasma performance and damage reactor components. Scintillator-based detectors are widely employed to monitor fast ions; however, existing studies often assume isotropic light emission, neglecting potential angular dependencies that can compromise the determination of ion fluxes. In this work, we investigate the angular emission properties of two commercial scintillators, TG-Green and b-SiAlON, under irradiation with 3.5 MeV He++ and 1 MeV D+ beams, representative of conditions in future fusion devices such as ITER. A novel experimental setup, combining precise optical alignment, angular scanning, and rigorous calibration, was developed to measure the detection efficiency as a function of observation angle. Prior to the characterization, stability tests demonstrated negligible radiation-induced degradation under the applied fluences, and transmission losses due to optical fiber bending were found to be below 1.5%. The results reveal a pronounced angular anisotropy in scintillation emission for both materials, with intensity decreasing as the detection angle increases, well described by an empirical cosine-based model. Additionally, the normalized response shows minimal dependence on ion species or energy. These findings improve scintillator-based diagnostics, allowing more accurate measurement of fast-ion fluxes in fusion plasmas. - oai:arXiv.org:2512.08501v1 - physics.ins-det - Wed, 10 Dec 2025 00:00:00 -0500 + Casimir radiation with Weyl semimetals + https://arxiv.org/abs/2512.09455 + arXiv:2512.09455v1 Announce Type: new +Abstract: When Casimir friction torque acts upon a rotated nanoparticle (NP), mechanical energy can be transformed into thermal energy, known as Casimir radiation, which significantly affects the thermal performance of nanoelectromechanical systems. In this work, we investigate Casimir radiation with nonreciprocal Weyl semimetals (WSM) NP levitated on a plate. WSM NP with inherent nonreciprocity has a radiative heat flux 27 times higher than NP with degenerate modes. The underlying physics is elucidated by the coupling and decoupling of the electromagnetic local density of states between nonreciprocal WSN NP and the plate in the near-field. The three-fold localized plasmon modes of WSM NP split into localized circular modes with strong gyrotropic response, which opens up new channels for Casimir radiation. This work provides a new method for nanoscale energy conversion in NP systems. + oai:arXiv.org:2512.09455v1 + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - M. Rodr\'iguez-Ramos, J. Garc\'ia-L\'opeza, M. Videla-Trevina, J. Gonz\'alez-Martinc, P. Alvarez-Fraub, M. Kocan + http://creativecommons.org/licenses/by/4.0/ + Yang Hu, Xiaohu Wu, Haotuo Liu, Mauro Antezza, Xiuquan Huang - Data-Efficient Learning of Anomalous Diffusion with Wavelet Representations: Enabling Direct Learning from Experimental Trajectories - https://arxiv.org/abs/2512.08510 - arXiv:2512.08510v1 Announce Type: new -Abstract: Machine learning (ML) has become a versatile tool for analyzing anomalous diffusion trajectories, yet most existing pipelines are trained on large collections of simulated data. In contrast, experimental trajectories, such as those from single-particle tracking (SPT), are typically scarce and may differ substantially from the idealized models used for simulation, leading to degradation or even breakdown of performance when ML methods are applied to real data. To address this mismatch, we introduce a wavelet-based representation of anomalous diffusion that enables data-efficient learning directly from experimental recordings. This representation is constructed by applying six complementary wavelet families to each trajectory and combining the resulting wavelet modulus scalograms. We first evaluate the wavelet representation on simulated trajectories from the andi-datasets benchmark, where it clearly outperforms both feature-based and trajectory-based methods with as few as 1000 training trajectories and still retains an advantage on large training sets. We then use this representation to learn directly from experimental SPT trajectories of fluorescent beads diffusing in F-actin networks, where the wavelet representation remains superior to existing alternatives for both diffusion-exponent regression and mesh-size classification. In particular, when predicting the diffusion exponents of experimental trajectories, a model trained on 1200 experimental tracks using the wavelet representation achieves significantly lower errors than state-of-the-art deep learning models trained purely on $10^6$ simulated trajectories. We associate this data efficiency with the emergence of distinct scale fingerprints disentangling underlying diffusion mechanisms in the wavelet spectra. - oai:arXiv.org:2512.08510v1 - physics.bio-ph + Deep learning of committor for ion dissociation and interpretable analysis of solvent effects using atom-centered symmetry functions + https://arxiv.org/abs/2512.09468 + arXiv:2512.09468v1 Announce Type: new +Abstract: The association and dissociation of ion pairs in water are fundamental to physical chemistry, yet their reaction coordinates are complex, involving not only interionic distance but also solvent-mediated hydration structures. These processes are often represented by free-energy landscapes constructed from collective variables (CVs), such as interionic distance and water bridging structures; however, it remains uncertain whether such representations reliably capture the transition pathways between the two associated and dissociated states. In this study, we employ deep learning to identify reaction coordinates for NaCl ion pair association and dissociation in water, using the committor as a quantitative measure of progress along the transition pathway through the transition state. The solvent environment surrounding the ions is encoded through descriptors based on atom-centered symmetry functions (ACSFs), which serve as input variables for the neural network. In addition, an explainable artificial intelligence technique is applied to identify ACSFs that contribute to the reaction coordinate. A comparative analysis of their correlation with CVs representing water bridging structures, such as interionic water density and the number of water molecules coordinating both ions, further provides a molecular-level interpretation of the ion association-dissociation mechanism in water. + oai:arXiv.org:2512.09468v1 + physics.chem-ph cond-mat.soft - cs.LG - physics.data-an - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Gongyi Wang, Yu Zhang, Zihan Huang + Kenji Okada, Kazushi Okada, Kei-ichi Okazaki, Toshifumi Mori, Kang Kim, Nobuyuki Matubayasi - Laser-pumped drilling carbon nanotube vortex shock waves in optical fibers - https://arxiv.org/abs/2512.08538 - arXiv:2512.08538v1 Announce Type: new -Abstract: We experimentally demonstrate laser-induced vortex shock waves formed by carbon nanotubes drilling optical fibers for the first time. Three samples of standard single-mode optical fibers (SMF) are sequentially inserted in a syringe loaded with a 1 mL solution of single-walled carbon nanotubes (CNT) and methanol, and a high-power laser is injected into the fibers for 5 (SMF 1), 10 (SMF 2), and 20 (SMF 3) minutes. The CNT solution thermally expands and generates vortex acoustic flows, which are confined in the syringe cavity, significantly increasing the velocity and impact of nanotubes at the fiber tip. The resulting shock waves achieve estimated hypersonic velocities (5742 m/s) and high pressures (6.7 GPa), overcoming the silica tensile strength and ablating structured vortices in the fibers. The material, geometry, and depth profile of the vortices are characterized, providing details of mixing carbon and silica layers, increasing radially from the fiber core center and in thickness to the cladding for longer laser periods (850 nm to 10 micron thickness). The cross-sections of the measured vortices are compared to analytical simulations, revealing unprecedented Fibonacci helices drilling holes in the fiber core with a 5 micron maximum depth, while depositing nanoscale CNT-silica layers following Fibonacci spirals. These achievements point out a new route for laser-controlled deposition of nanoparticles and fabrication of vortex devices on fiber tips, which is promising for all-fiber vortex spatial phase modulators in optical communications, fiber sensors, high-power pulsed fiber lasers, and biomedical ultrasonic neurotransmitters. - oai:arXiv.org:2512.08538v1 + High-resolution broadband characterization of resonance dispersion in an optical microresonator + https://arxiv.org/abs/2512.09475 + arXiv:2512.09475v1 Announce Type: new +Abstract: Accurate knowledge of the uneven free spectral range of an optical microresonator, which provides direct insight into group velocity dispersion, is essential for understanding and controlling Kerr frequency comb dynamics. In this work, we present a simple and highly precise method formeasuring the free spectral range over a 5 THz bandwidth in silicon nitride microresonators, leveraging a wavemeter with 0.4 MHz resolution. Our fully fibered plug-and-play experimental setup enables the accurate extraction of resonance frequencies. By carefully analyzing the spectral position of each resonance, we measure both second- and third-order free spectral range expansion coefficients. This approach offers a robust and accessible tool for dispersion characterization in integrated photonic circuits, paving the way for next-generation of Kerr comb sources and quantum photonic technologies. + oai:arXiv.org:2512.09475v1 physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + quant-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Ricardo E. da Silva, Marcos A. R. Franco - - - Polarization Dependent Enhancement of Magnetic Dipolar Emission with Silicon Nanodimers - https://arxiv.org/abs/2512.08546 - arXiv:2512.08546v1 Announce Type: new -Abstract: Eu(TTA)3 complexes are used as an emission source in the presence of high refrac- tive index dielectric nanostructures. These nanostructures support Mie-type resonances that modify the local density of optical states. Specifically, the silicon dimer provides polarization-dependent electric and magnetic field enhancement in the dimer gap to modify the electric dipolar and magnetic dipolar emissions of the Eu3+ at 610 nm and 590 nm, respectively. Finite element method simulations are used to determine the opti- mal parameters for the sample and to demonstrate the polarization-dependent emission enhancement of dipolar emitters in the gap. A two-step electron beam lithography pro- cess is used to fabricate the hybrid nanoscopic structures, with a Eu3+ doped electron beam resist located only in the center of the dimer. The results demonstrate the po- tential of these nanostructures to selectively tailor the emission of the two distinct dipolar transitions by engineering the resonant nanostructures. Our work highlights the potential of magnetic light-matter interactions as a novel degree of freedom. - oai:arXiv.org:2512.08546v1 - physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 - new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Marijn Rikers, Ayesheh Bashiri, Aleksandr Vaskin, \'Angela Barreda, Duk-Yong Choi, Michael Steinert, Thomas Pertsch, Isabelle Staude + Romain Dalidet, Adrien Bensemhoun, Gregory Sauder, Anthony Martin, David Medina, Carlos Alonso Ramos, Eric Cassan, Laurent Vivien, Jonathan Faugier Tovar, Baptiste Routier, Quentin Wilmart, S\'egol\`ene Olivier, Virginia D Auria, Laurent Labont\'e, S\'ebastien Tanzilli - A journey to ITACA - https://arxiv.org/abs/2512.08549 - arXiv:2512.08549v1 Announce Type: new -Abstract: A unique feature of gas xenon electroluminescent time projection chambers (GXeEL TPCs) in $0\nu\beta\beta$ searches is their ability to reconstruct event topology, in particular to distinguish "single-electron" from "double-electron" tracks, the latter being the signature of a $0\nu\beta\beta$ decay near the decay endpoint $Q_{\beta\beta}$. Together with excellent energy resolution and the t$_0$ provided by primary scintillation, this topological information is key to suppressing backgrounds. Preserving EL, however, requires operating in pure xenon (with helium as the only benign additive), and in pure xenon the diffusion of drifting electrons is large. As a result, the fidelity of reconstructed tracks is limited both by diffusion and by the intrinsic blurring of EL amplification. - We propose augmenting the detector with the ability to image not only the electron track but also the corresponding mirror ion track. Introducing trace amounts of NH$_3$ ($\sim$100 ppb) converts Xe$^+$ ions into NH$_4^+$ while leaving EL unaffected. For events in the region-of-interest, an ion sensor positioned near the cathode at the projected barycenter captures the NH$_4^+$ ions. Electrons drift rapidly to the anode, producing the standard EL image, whereas the NH$_4^+$ ions drift slowly toward the cathode. Their slow drift provides time to determine the event energy and barycenter. Laser interrogation of the sensor's molecular layer then reveals an ion-track image with sub-millimeter diffusion and no EL-induced smearing. - The combined electron-ion imaging substantially strengthens topological discrimination, improving background rejection by about an order of magnitude and significantly extending the discovery potential of GXeEL TPCs for very long $0\nu\beta\beta$ lifetimes. - oai:arXiv.org:2512.08549v1 + Commissioning of a mobile neutron spectrometer for LNGS + https://arxiv.org/abs/2512.09482 + arXiv:2512.09482v1 Announce Type: new +Abstract: Environmental neutrons are a source of background for rare event searches in underground laboratories. Since the majority of the neutron background comes from the cavern walls due to the intrinsic radioactivity of concrete and rock, the flux is known to be time and location dependent. Therefore, a precise knowledge of the spectrum and of the total flux is needed to devise shielding and veto mechanisms for rare event searches. Here ALMOND (An LNGS Mobile Neutron Detector) is presented. It is a mobile neutron spectrometer, based on capture-gated spectroscopy and comprised of an array of plastic scintillator bars wrapped with gadolinium foils. The detector has been calibrated with Americium-Beryllium source at Karlsruhe Institute of Technology and with an Americium-Boron source and a D-D generator at ENEA Frascati. The results of the neutron calibration with the time of flight method and the D-D generator are shown here, alongside the first results on capture time profile. Moreover, the first results from the neutron background run in Hall A at LNGS are presented. + oai:arXiv.org:2512.09482v1 physics.ins-det hep-ex - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - J. J. G\'omez-Cadenas, L. Arazi, M. Elorza, Z. Freixa, F. Monrabal, A. Pazos, J. Renner, S. R. Soleti, S. Torelli - - - Matrix-free algorithms for fast ab initio calculations on distributed CPU architectures using finite-element discretization - https://arxiv.org/abs/2512.08571 - arXiv:2512.08571v1 Announce Type: new -Abstract: Finite-element (FE) discretisations have emerged as a powerful real-space alternative to large-scale Kohn-Sham density functional theory (DFT) calculations, offering systematic convergence, excellent parallel scalability, while accommodating generic boundary conditions. However, the dominant computational bottleneck in FE-based DFT arises from the repeated application of the discretised sparse Hamiltonian to large blocks of trial vectors during iterations in an iterative eigensolver. Traditional sparse matrix-vector multiplications and FE cell-matrix approaches encounter memory limitations and high data-movement overheads, particularly at higher polynomial orders, typically used in DFT calculations. To overcome these challenges, this work develops matrix-free algorithms for FE-discretised DFT that substantially accelerate these products by doing on-the-fly operations that utilize structured tensor contractions over 1D basis functions and quadrature data. A unified multilevel batched data layout that handles both real and complex-valued operators is introduced to maximise cache reuse and SIMD utilisation on Frontier (AVX2), Param Pravega (AVX512) and Fugaku (SVE). We also combine terms for optimal cache reuse, even-odd decomposition to reduce FLOP, and mixed-precision intrinsics. Extensive benchmarks show that for large multivector pseudopotential DFT calculations, the matrix-free kernels deliver 1.5-4x speedups over the state-of-the-art cell-matrix approach baselines. For all-electron DFT calculations, the matrix-free operator achieves gains of up to 5.8x due to its efficient implementation and superior arithmetic intensity. When integrated with an error-tolerant Chebyshev-filtered subspace iteration eigensolver, the matrix-free formalism yields substantial reductions in end-to-end time-to-solution using FE meshes that deliver desired accuracies in ground-state properties. - oai:arXiv.org:2512.08571v1 - physics.comp-ph - Wed, 10 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/publicdomain/zero/1.0/ - Phani Motamarri, Gourab Panigrahi + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Francesco Pompa, Klaus Eitel, Alfredo Davide Ferella, Felix Kratzmeier, Melih Solmaz, Kathrin Valerius - Study of a small-scale gamma-ray detection system employing Compton scattering with a monolithic CeBr3 crystal and segmented photodetector array - https://arxiv.org/abs/2512.08593 - arXiv:2512.08593v1 Announce Type: new -Abstract: Study of high energy cosmic events in the MeV range requires detector with high efficiency and energy resolution to be constructed. The present setup consisting of scintillator crystals CeBr3 with different thickness, each coupled with 12 x 12 segmented SiPM-based photodetector in a multichannel system represents an initial exploration of a gamma imaging system based on Compton scattering principles. A Monte Carlo simulation was conducted to evaluate the energy deposit and detection efficiency using the 137Cs gamma line. The study reveals a correlation between the relative distance between detector planes and the energy deposition efficiency, providing valuable insights into optimizing the telescope design. - oai:arXiv.org:2512.08593v1 - physics.ins-det - Wed, 10 Dec 2025 00:00:00 -0500 + Emergence of edge state in suspension of self-propelled particles + https://arxiv.org/abs/2512.09491 + arXiv:2512.09491v1 Announce Type: new +Abstract: We numerically study a model convection system of a suspension of self-propelled particles, motivated by recent experimental findings of localized and bistable bioconvection pattern, being distinct from classical Rayleigh--B\'{e}nard convection. Linear stability analysis of the model system reveals that the trivial noncovection state is stabilized by an increase of self-propelled speed in the vertical direction. Through numerical simulations, we found a nonlinear convection state even when the nonconvection state is stable. Applying ideas and tools developed in wall-bounded flows, we numerically identified an edge state, which is an unstable solution on a basin boundary in the model dynamical systems. + oai:arXiv.org:2512.09491v1 + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1088/1742-6596/3116/1/012007 - Journal of Physics: Conference Series 3116 (2025) 012007 - Veronika Asova, Galin Bistrev, Simeon Ivanov + Yoshiki Hiruta, Kenta Ishimoto - Pulse Shape Discrimination for Germanium Detectors using Variational Quantum Circuits - https://arxiv.org/abs/2512.08603 - arXiv:2512.08603v1 Announce Type: new -Abstract: Pulse shape discrimination (PSD) is a critical component in background rejection for neutrinoless double-beta decay and dark matter searches using Broad Energy Germanium (BEGe) detectors. To date, advanced discrimination has relied on Deep Learning approaches employing e.g. Denoising Autoencoders (DAE) and Convolutional Neural Networks (CNN). While effective, these models require tens of thousands of parameters and heavy pre-processing. In this work, we present, to the best of our knowledge, the first application of Quantum Machine Learning (QML) to real, experimental pulse waveforms from a germanium detector. We propose a quantum-classical hybrid approach using Variational Quantum Circuits (VQC) with amplitude encoding. By mapping the 1024-sample waveforms directly into a 10-qubit Hilbert space, we demonstrate that a VQC with only 302 trainable parameters achieves a receiver operating characteristic (ROC) area under the curve (AUC) of 0.98 and a global accuracy of 97.1%. This result demonstrates that even in the current Noisy Intermediate-Scale Quantum (NISQ) era, quantum models can match the performance of state-of-the-art classical baselines while reducing model complexity by over two orders of magnitude. Furthermore, we envision a scenario where future quantum sensors transmit quantum states directly to such processing units, exploiting the exponentially large Hilbert space in a natively quantum pipeline. - oai:arXiv.org:2512.08603v1 - physics.ins-det - hep-ex - nucl-ex - Wed, 10 Dec 2025 00:00:00 -0500 + Avalanches of choice: how stranger-to-stranger interactions shape crowd dynamics + https://arxiv.org/abs/2512.09522 + arXiv:2512.09522v1 Announce Type: new +Abstract: Pedestrian routing choices play a crucial role in shaping collective crowd dynamics, yet the influence of interactions among unfamiliar individuals remains poorly understood. In this study, we analyze real-world pedestrian behavior at a route split within a busy train station using high-resolution trajectory data collected over a three-year time frame. We disclose a striking tendency for individuals to follow the same path as the person directly in front of them, even in the absence of social ties and even when such a choice leads to a longer travel time. This tendency leads to bursty dynamics, where sequences of pedestrians make identical decisions in succession, leading to strong patterns in collective movement. We employ a stochastic model that includes route costs, randomness, and social imitation to accurately reproduce the observed behavior, highlighting that local imitation behavior is the dominant driver of collective routing choices. These findings highlight how brief, low-level interactions between strangers can scale up to influence large-scale pedestrian movement, with strong implications for crowd management, urban design, and the broader understanding of social behavior in public spaces. + oai:arXiv.org:2512.09522v1 + physics.soc-ph + physics.app-ph + physics.data-an + Thu, 11 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Fabrizio Napolitano + http://creativecommons.org/licenses/by/4.0/ + Ziqi Wang, Alessandro Gabbana, Federico Toschi - Modeling of van-der-Meer scan at NICA - https://arxiv.org/abs/2512.08605 - arXiv:2512.08605v1 Announce Type: new -Abstract: Van-der-Meer method is used in hadron colliders for absolute luminosity calibration. In the letter the applicability of the method is discussed when particles desnsity is distorted by hour-glass effect next to interaction point. The study is motivated by close commisioning of Nuclotron based Ion Collider fAcility where hour-glass effected is significant by design. The theoretical van-der-Meer formalism is revised for this case. Importance of hour-glass effect for luminosity measurements and calibration is demonstrated. Also, the general approach to the estimation of van-der-Meer method bias when it is used for non-factorizable beams is proposed. - oai:arXiv.org:2512.08605v1 - physics.acc-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Data-driven time-dependent bases for turbulent airfoil wake-extreme vortex gust interactions + https://arxiv.org/abs/2512.09523 + arXiv:2512.09523v1 Announce Type: new +Abstract: We analyze interactions between turbulent airfoil wake and an extremely strong gust using a data-driven framework with time-dependent bases. The current approach represents each snapshot with time-varying bases consisting of two-dimensional in-plane modes and one-dimensional spanwise modes, together with a reduced covariance matrix. We derive closed-form evolution equations for these time-varying components and advance them over time, requiring only a small rolling window and avoiding full-history storage. Applied to extreme vortex gust-airfoil interaction at Re=5000, we examine how in-plane modes and their associated energy level evolve across gust conditions of varying intensity and size. Before impingement, the first in-plane mode dominates; after impingement, the second mode gains energy_amplified by stronger/larger gusts. A larger leading-mode energy gap implies coherent structure and faster recovery; a smaller gap with slower decay indicates richer multiscale activity and delayed re-stabilization. These trends follow the transient lift dynamics as well, with higher amplitude and more oscillations indicated by a rise in the leading singular values. This work provides an interpretable, time-varying data-driven modal analysis of extreme gust encounter. + oai:arXiv.org:2512.09523v1 + physics.comp-ph + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Anton Babaev + Shaghayegh Zamani Ashtiani, Kai Fukami - PyMieDiff: A differentiable Mie scattering library - https://arxiv.org/abs/2512.08614 - arXiv:2512.08614v1 Announce Type: new -Abstract: Light scattering by spherical-shaped particles of sizes comparable to the wavelength is foundational in many areas of science, from chemistry to atmospheric science, photonics and nanotechnology. With the new capabilities offered by machine learning, there is a great interest in end-to-end differentiable frameworks for scattering calculations. Here we introduce PyMieDiff, a fully differentiable, GPU-compatible implementation of Mie scattering for core-shell particles in PyTorch. The library provides native, autograd-compatible spherical Bessel and Hankel functions, vectorized evaluation of Mie coefficients, and APIs for computing efficiencies, angular scattering, and near-fields. All inputs - geometry, material dispersion, wavelengths, and observation angles and positions - are represented as tensors, enabling seamless integration with gradient-based optimisation or physics-informed neural networks. The toolkit can also be combined with "TorchGDM" for end-to-end differentiable multi-particle scattering simulations. PyMieDiff is available under an open source licence at https://github.com/UoS-Integrated-Nanophotonics-group/MieDiff. - oai:arXiv.org:2512.08614v1 + Four-wave Mixing Mediated Synchronization of Localized Polariton Condensates + https://arxiv.org/abs/2512.09531 + arXiv:2512.09531v1 Announce Type: new +Abstract: The Letter is devoted to new frequencies generation and its role in the synchronization of two spatially separated polariton condensates affected by the coherent pump with the frequency detuned from the frequencies of the condensates. We focus on the case where the distance between the condensates is so long that their interaction through the evanescent tails is negligible. By numerical simulation we show that the four-wave mixing of the polaritons with the coherent drive produces the free propagating polaritons that can mediate the inter-condensate interaction resulting in the phase-locking of the condensates. + oai:arXiv.org:2512.09531v1 physics.optics - physics.comp-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Oscar K. C. Jackson, Simone De Liberato, Otto L. Muskens, Peter R. Wiecha + Alexey V Yulin - Gradient-based optimization of scatterer arrangements based on the T-Matrix method - https://arxiv.org/abs/2512.08615 - arXiv:2512.08615v1 Announce Type: new -Abstract: The demand for inverse design is increasing as the ability to fabricate sub-10 nm features expands the design space by orders of magnitude. Efficient inverse design benefits from differentiable models of light-structure interaction. While traditional full-wave solvers based on finite differences, finite elements, or Fourier modal methods have already been presented for that purpose, a dedicated tool adapted for performing multiple scattering simulations is still lacking. To overcome this limitation, we provide a multiple-scattering framework compatible to automatic differentiation, suitable for treating periodic and non-periodic arrangements of scatterers. It yields exact gradients regarding geometric and positional parameters in finite clusters and infinite metasurfaces. In this work, we use spheres as the elementary building blocks to demonstrate the framework's capabilities as a standalone tool. However, the framework is adaptable to arbitrarily shaped scatterers, provided the individual T-matrices are calculated using differentiable full-wave Maxwell solvers. Since the gradients are obtained simultaneously in a single backward pass, the framework is well-suited for moderately dimensional problems. It is also possible to combine multiple performance goals into a single objective function. The versatility of our method is illustrated in proof-of-concept examples that focus on various aspects of Kerker-type physics. In the first example, a finite cluster of scatterers is optimized in order to reach a high forward-to-backward scattering ratio, and we show experimental feasibility of the designs. In the second example, a metasurface made from multiple scatterers in each unit cell is designed to maximize the reflectance contrast between orthogonal linear polarizations of the incident light. We make the framework publicly available at https://github.com/tfp-photonics/dreams. - oai:arXiv.org:2512.08615v1 + Cathodoluminescence Study of a Quantum Dot in a Nanowire for Single-Photon Emission + https://arxiv.org/abs/2512.09542 + arXiv:2512.09542v1 Announce Type: new +Abstract: Cathodoluminescence in a scanning electron microscope was applied to a semiconductor quantum dot in a nanowire able to emit single photons. We show that cathodoluminescence can be used not only for imaging and spectroscopy, but also to measure the correlation function and characterize the purity of the single-photon emitter. The electron beam can be manipulated to minimize the collection of parasitic luminescence. At cryogenic temperatures, we observed that the thermal budget, as measured via the phonon sidebands, is close to that of non-resonant micro-photoluminescence. This makes cathodoluminescence an efficient tool in the quest of novel single-photon sources. + oai:arXiv.org:2512.09542v1 physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Nigar Asadova (Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe, Germany), Jan David Fischbach (Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe, Germany), Renaud Vall\'ee (Centre de Recherche Paul Pascal, University of Bordeaux, Pessac, France), Yannick Augenstein (Flexcompute Inc, Belmont, MA, USA), Dmytro Vovchuk (Institute of Photonics, Electronics and Telecommunications, Riga Technical University, Riga, Latvia), Anton Kharchevskii (School of Electrical Engineering, Tel Aviv University, Tel Aviv, Israel), Pavel Ginzburg (School of Electrical Engineering, Tel Aviv University, Tel Aviv, Israel), Carsten Rockstuhl (Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe, Germany) + http://creativecommons.org/licenses/by/4.0/ + Francis Granger, Fabrice Donatini, Edith Bellet-Amalric, Kuntheak Kheng, Gilles Nogues, David Ferrand, Joel Cibert - Stretching and breaking of particles in compressible random flows - https://arxiv.org/abs/2512.08632 - arXiv:2512.08632v1 Announce Type: new -Abstract: A key feature of turbulent suspensions that involve floating particles on the surface or inertial particles in the bulk is the compressibility of the effective particle-phase velocity field. Little, however, is known about the effects of small-scale flow compressibility on the stretching and breaking of particles. Here, we gain insight into the nature of these effects by studying the deformation of tiny particles in model fluctuating flows. We consider a generic particle with extensional dynamics that are governed by a vector model, which accounts for elasticity, internal viscosity, and non-affine deformation. Applying the dynamical systems approach of Balkovsky, Fouxon & Lebedev (2000), we first obtain general results for the stationary statistics of particle extension in compressible chaotic flows. We then specialize to a time-decorrelated Gaussian random flow and derive an exact solution for the Batchelor regime of the compressible Kraichnan model. We also perform numerical simulations for a time-correlated renewing flow. While straining is suppressed on the average in compressible flows, our results show that large deviations of the strain rate strongly stretch particles and give rise to a power-law distribution of extensions. Extreme straining events are particularly important for stiff particles and, in the examples considered here, give rise to a counter-intuitive effect: stiff particles stretch more and break faster in flows of increasing compressibility. Highly-elastic particles, whose deformation is dictated by the mean straining, stretch less and break slower. Though based on specific random flows, our work shows how compressibility can affect the extensional dynamics of particles by altering the fluctuations of the strain rate, including its large deviations. - oai:arXiv.org:2512.08632v1 - physics.flu-dyn - cond-mat.stat-mech - nlin.CD - Wed, 10 Dec 2025 00:00:00 -0500 + A State-Space-View of Atom-Diatom Reactions Relevant to Rarefied Gas Flow + https://arxiv.org/abs/2512.09545 + arXiv:2512.09545v1 Announce Type: new +Abstract: A microscopically resolved picture of energy flow in atom-diatom collisions is essential for understanding the non-equilibrium chemistry in rarefied and hypersonic gas flow. Here, a comprehensive ensemble of quasi-classical trajectories on global, reactive, and ``vetted'' potential energy surfaces are employed to construct state-resolved probability maps and to determine the dependence of the outcomes on the initial ro-vibrational states $(v,j)$. The full range of processes, including elastic, inelastic, atom exchange, reactive, and atomization are quantified, revealing distinct structure reactivity relationships. For the [OOO] system consistent trends are obtained from two high-quality potential energy surfaces, despite their different electronic structure and representation techniques. The resulting state-space description provides a comprehensive picture of energy redistribution in high-energy atom-diatom collisions, forming a basis for improved modeling of non-equilibrium chemistry in hypersonic and rarefied environments. + oai:arXiv.org:2512.09545v1 + physics.chem-ph + Thu, 11 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Dipankar Roy, Marco Martins Afonso, Jason R. Picardo, Dario Vincenzi + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Abhirami Vijayakumar, Raidel Martin-Barrios, Markus Meuwly - Centrifugal instability of Taylor-Couette flow in stratified and diffusive fluids - https://arxiv.org/abs/2512.08664 - arXiv:2512.08664v1 Announce Type: new -Abstract: The linear and non-linear dynamics of centrifugal instability in Taylor-Couette flow are investigated when fluids are stably stratified and highly diffusive. One-dimensional local linear stability analysis (LSA) on cylindrical Couette flow confirms that the stabilising role of stratification on centrifugal instability is suppressed by strong thermal diffusion (i.e. low Prandtl number $Pr$). For $Pr\ll1$, it is verified that the instability dependence on thermal diffusion and stratification with the non-dimensional Brunt-V\"ais\"al\"a frequency $N$ can be prescribed by a single rescaled parameter $P_{N}=N^{2}Pr$. From direct numerical simulation (DNS), various non-linear features such as axisymmetric Taylor vortices at saturation, secondary instability leading to non-axisymmetric patterns or transition to chaotic states are investigated for various values of $Pr\leq1$ and the Reynolds number $Re_{i}$. Two-dimensional bi-global LSA on axisymmetric Taylor vortices, which appear as primary centrifugal instability saturates nonlinearly, is also performed to find the secondary critical Reynolds number $Re_{i,2}$ at which the Taylor vortices become unstable by non-axisymmetric perturbation. The bi-global LSA reveals that $Re_{i,2}$ increases (i.e. the onset of secondary instability is delayed) in the range $10^{-3}<Pr<1$ at $N=1$ or as $N$ increases at $Pr=0.01$. Secondary instability leading to highly non-axisymmetric or irregular chaotic patterns is further investigated by the 3D DNS. The Nusselt number $Nu$ is also computed from the torque at the inner cylinder for various $Pr$ and $Re_{i}$ at $N=1$ to describe how the angular momentum transfer increases with $Re_{i}$ and how $Nu$ varies differently for saturated and chaotic states. - oai:arXiv.org:2512.08664v1 + Lazy Diffusion: Mitigating spectral collapse in generative diffusion-based stable autoregressive emulation of turbulent flows + https://arxiv.org/abs/2512.09572 + arXiv:2512.09572v1 Announce Type: new +Abstract: Turbulent flows posses broadband, power-law spectra in which multiscale interactions couple high-wavenumber fluctuations to large-scale dynamics. Although diffusion-based generative models offer a principled probabilistic forecasting framework, we show that standard DDPMs induce a fundamental \emph{spectral collapse}: a Fourier-space analysis of the forward SDE reveals a closed-form, mode-wise signal-to-noise ratio (SNR) that decays monotonically in wavenumber, $|k|$ for spectra $S(k)\!\propto\!|k|^{-\lambda}$, rendering high-wavenumber modes indistinguishable from noise and producing an intrinsic spectral bias. We reinterpret the noise schedule as a spectral regularizer and introduce power-law schedules $\beta(\tau)\!\propto\!\tau^\gamma$ that preserve fine-scale structure deeper into diffusion time, along with \emph{Lazy Diffusion}, a one-step distillation method that leverages the learned score geometry to bypass long reverse-time trajectories and prevent high-$k$ degradation. Applied to high-Reynolds-number 2D Kolmogorov turbulence and $1/12^\circ$ Gulf of Mexico ocean reanalysis, these methods resolve spectral collapse, stabilize long-horizon autoregression, and restore physically realistic inertial-range scaling. Together, they show that na\"ive Gaussian scheduling is structurally incompatible with power-law physics and that physics-aware diffusion processes can yield accurate, efficient, and fully probabilistic surrogates for multiscale dynamical systems. + oai:arXiv.org:2512.09572v1 physics.flu-dyn - astro-ph.SR - Wed, 10 Dec 2025 00:00:00 -0500 + cs.AI + math.DS + nlin.CD + physics.ao-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - 10.1017/jfm.2025.261 - Junho Park + Anish Sambamurthy, Ashesh Chattopadhyay - Atomic and molecular systems for radiation thermometry - https://arxiv.org/abs/2512.08668 - arXiv:2512.08668v1 Announce Type: new -Abstract: Atoms and simple molecules are excellent candidates for new standards and sensors because they are both all identical and their properties are determined by the immutable laws of quantum physics. Here, we introduce the concept of building a standard and sensor of radiative temperature using atoms and molecules. Such standards are based on precise measurement of the rate at which blackbody radiation (BBR) either excites or stimulates emission for a given atomic transition. We summarize the recent results of two experiments while detailing the rate equation models required for their interpretation. The cold atom thermometer (CAT) uses a gas of laser cooled $^{85}$Rb Rydberg atoms to probe the BBR spectrum near 130~GHz. This primary, {\it i.e.}, not traceable to a measurement of like kind, temperature measurement currently has a total uncertainty of approximately 1~\%, with clear paths toward improvement. The compact blackbody radiation atomic sensor (CoBRAS) uses a vapour of $^{85}$Rb and monitors fluorescence from states that are either populated by BBR or populated by spontaneous emission to measure the blackbody spectrum near 24.5~THz. The CoBRAS has an excellent relative precision of $u(T)\approx 0.13$~K, with a clear path toward implementing a primary - oai:arXiv.org:2512.08668v1 + Table-top all-attosecond transient absorption spectrscopy + https://arxiv.org/abs/2512.09585 + arXiv:2512.09585v1 Announce Type: new +Abstract: Attosecond transient absorption spectroscopy (ATAS) has emerged as a powerful technique within the field of attosecond science, combining extremely high temporal and excellent spectral resolution. So far, ATAS has been implemented in pump-probe experiments where an attosecond extreme-ultraviolet (XUV) pump or probe pulse was combined with a near-infrared (NIR) pulse in the femtosecond range, with the attosecond time resolution deriving from sub-cycle NIR-driven dynamics. Investigations of ultrafast electron dynamics in atoms, molecules and solids, with potential impact across physics, chemistry, and biology, would benefit significantly from the ability to perform all-attosecond transient absorption spectroscopy (AATAS). Here we demonstrate time-resolved AATAS using a table-top high-harmonic generation (HHG) source. The method is applied to investigate previously unresolved electronic coherences in Xe, revealing oscillatory valence hole motion with a 3-femtosecond period. In addition, systematic investigations of electron dynamics in Kr, Ar, and Ne are presented. Our work shows that, thanks to its broad bandwidth, high stability and easy accessibility, HHG is an ideal source for AATAS, offering the potential for replication in numerous laboratories. + oai:arXiv.org:2512.09585v1 physics.atom-ph - Wed, 10 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/publicdomain/zero/1.0/ - Stephen P. Eckel, Eric B. Norrgard, Christopher Holloway, Nikunjkumar Prajapati, Noah Schlossberger, Matthew Simons - - - Machine learning for smell: Ordinal odor strength prediction of molecular perfumery components - https://arxiv.org/abs/2512.08683 - arXiv:2512.08683v1 Announce Type: new -Abstract: Predicting olfactory perception directly from molecular structure is central to fragrance design that plays a role in a wide range of industries, such as perfumery, food and beverage, and health care. Among olfactory attributes, odor strength is a key factor in shaping odor perception, but its modeling has been impeded by scarce and fragmented intensity data. In this work, we introduce an ordinal odor strength data set of over 2,000 molecules by integrating two different public sources, mapping structures to odorless, low, medium, and high categories. Across several molecular encodings and supervised learning algorithms we compared different prediction strategies. Dimensionality reduction and SHAP analysis identifies molecular size, polarity, ring features, and branching as primary drivers, consistent with mass-transport constraints on volatility, sorption, and receptor access. This scalable ordinal framework enables reliable odor-strength estimation for novel molecules and provides a foundation for in silico fragrance design. - oai:arXiv.org:2512.08683v1 - physics.chem-ph - Wed, 10 Dec 2025 00:00:00 -0500 + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Peter Fichtelmann, Julia Westermayr + Mikhail Volkov, Evaldas Svirplys, Stefanos Carlstr\"om, Serguei Patchkovskii, Misha Yu. Ivanov, Marc J. J. Vrakking, Bernd Sch\"utte - Plasma waveguides for high-intensity laser pulses - https://arxiv.org/abs/2512.08690 - arXiv:2512.08690v1 Announce Type: new -Abstract: Fundamental to many applications of laser pulses in science and technology is an extended interaction length with matter that significantly exceeds the distance over which the pulse would normally diffract and transversely spread. At low intensity, the interaction could simply be the linear refraction provided by a glass optical fiber to keep the pulse from spreading. At increased pulse intensity, more than diffraction-free pulse transport is of interest: an extended interaction length of high intensity light can give rise to bright secondary sources of photons, and at relativistic intensities, beams of high energy charged particles. As generation of these secondary sources requires laser intensities well above the threshold for ionization of atoms, new methods for defeating pulse diffraction in a plasma have been developed. Chief among them are plasma waveguides: optical fibers composed of plasma that have characteristic mode structure. This article reviews the methods and theory of plasma waveguides, highlighting the recent development of meter-scale plasma waveguides that have been instrumental to the laser acceleration of high charge electron beams to ~10 GeV. - oai:arXiv.org:2512.08690v1 - physics.plasm-ph - physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + Noise dissipation mechanisms of an acoustic liner under grazing flow + https://arxiv.org/abs/2512.09587 + arXiv:2512.09587v1 Announce Type: new +Abstract: High-fidelity lattice-Boltzmann very-large-eddy simulations are performed to describe the noise dissipation mechanisms in an acoustic liner subjected to grazing turbulent flow at a Mach number of 0.3 and plane acoustic waves. The study examines the effects of sound pressure level (ranging from 130 to 160 dB) and frequency, as well as the direction of acoustic-wave propagation relative to the grazing flow. The considered mechanisms of acoustic energy dissipation are the viscous losses along the internal walls of the orifice and the vortex shedding. The latter is quantified through Howe's energy corollary. In the absence of grazing flow, acoustic energy is dissipated almost equally during both inflow and outflow phases, with vortex shedding dominating at high SPL and viscous losses at low SPL. The introduction of a grazing flow alters the flow topology; in particular, the shear layer past the orifice generates a quasi-steady vortex that confines the acoustic-induced flow to the downstream half of the orifice. This topological change modifies the two noise dissipation mechanisms: viscous losses increase at low SPL because the grazing flow pushes the fluid toward the downstream lip of the orifice; vortex shedding becomes phase dependent, dissipating acoustic energy during the inflow phase and generating acoustic energy during the outflow phase. This explains why the net acoustic dissipation decreases in the presence of grazing flow, highlighting the crucial role of near-wall flow topology on liner performances. + oai:arXiv.org:2512.09587v1 + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - J. E. Shrock, B. Miao, E. Rockafellow, H. M. Milchberg + Francesco Scarano, Angelo Paduano, Francesco Avallone - Electron Emission Yield Datasets Under Electron Impact From Surfaces Characterized In Situ by XPS or AES - https://arxiv.org/abs/2512.08693 - arXiv:2512.08693v1 Announce Type: new -Abstract: We present the measurement, characterization, and calibration procedures used to produce a series of datasets for various conductive and semiconductive materials. The data, provided, include emission yields as a function of incident electron energy together with surface composition obtained from X-Ray Photoelectron Spectroscopy or Auger Electron Spectroscopy analyses. Initial datasets cover copper and gold, with additional materials to be released on arXiv. - oai:arXiv.org:2512.08693v1 - physics.app-ph - cond-mat.mtrl-sci - Wed, 10 Dec 2025 00:00:00 -0500 + Advanced microwave SQUID multiplexer model incorporating readout power effects and Josephson junction inhomogeneities + https://arxiv.org/abs/2512.09600 + arXiv:2512.09600v1 Announce Type: new +Abstract: We present an advanced model for describing the readout power dependence of the resonance characteristics of a microwave SQUID multiplexer. Our model proves valid for SQUID screening parameters up to $\beta_\mathrm{L}<1$, hence covering the full range of practically relevant design parameters. We demonstrate that our model significantly improves agreement with experimental data compared to the existing models, thereby enabling optimization beyond the previously accessible parameter space. Moreover, our model supports non-sinusoidal current-phase relations of the rf-SQUID's Josephson junction, allowing, for the first time, for the modeling of devices based on Josephson tunnel junctions with inhomogeneous tunnel barriers. We show that the effects of such inhomogeneities are qualitatively similar to, yet distinct from, those of the screening parameter, making their inclusion essential for accurate characterization. Incorporating these effects yields great improved agreement with measurements, even at readout power conditions well beyond typical operating parameters. + oai:arXiv.org:2512.09600v1 + physics.ins-det + cond-mat.supr-con + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-sa/4.0/ - M. Belhaj, S. dadouch + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Martin Neidig, Mathias Wegner, Sebastian Kempf - Incoherent repumping scheme in the $^{88}$Sr$^{+}$ five-level manifold - https://arxiv.org/abs/2512.08710 - arXiv:2512.08710v1 Announce Type: new -Abstract: Laser-cooled trapped ions are at the heart of modern quantum technologies and their cooling dynamics often deviate from the simplified two-level atom model. Doppler cooling of the $^{88}$Sr$^{+}$ ion involves several electronic levels and repumping channels that strongly influence fluorescence.In this work, we study a repumping scheme for the $^{88}$Sr$^{+}$ ion by combining precision single-ion spectroscopy with comprehensive numerical modeling based on optical Bloch equations including 18 Zeeman sublevels. We show that, although the observed fluorescence spectra retain a Lorentzian lineshape, their width and amplitude cannot be explained by a two-level atom description. Moreover, we find the optimal repumping conditions for maximizing the photon scattering rate. - oai:arXiv.org:2512.08710v1 - physics.atom-ph - Wed, 10 Dec 2025 00:00:00 -0500 + A unified framework for identifying influential nodes in hypergraphs + https://arxiv.org/abs/2512.09606 + arXiv:2512.09606v1 Announce Type: new +Abstract: Identifying influential nodes plays a pivotal role in understanding, controlling, and optimizing the behavior of complex systems, ranging from social to biological and technological domains. Yet most centrality-based approaches rely on pairwise topology and are purely structural, neglecting the higher-order interactions and the coupling between structure and dynamics. Consequently, the practical effectiveness of existing approaches remains uncertain when applied to complex spreading processes. To bridge this gap, we propose a unified framework, Initial Propagation Score (IPS), to directly embed propagation dynamics into influence assessment on higher-order networks. We analytically derive mechanism-aware influence measures by relating the early-stage dynamics and local topological characteristics to long-term outbreak sizes, and such explicit physical context endows IPS with robustness, transferability, and interpretability. Extensive experiments across multiple dynamics and more than 20 real-world hypergraphs show that IPS consistently outperforms other leading baseline centralities. Furthermore, IPS estimates node influence with only local neighborhood information, yielding computational efficiency and scalability to large-scale networks. This work underscores the necessity of considering dynamics for reliable identification of influential nodes and provides a concise principled basis for optimizing interventions in epidemiology, information diffusion, and collective intelligence. + oai:arXiv.org:2512.09606v1 + physics.soc-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Valentin Martimort, Sacha Guesne, Derwell Drapier, Vincent Tugaye, Lilay Gros-Desormeaux, Valentin Cambier, Albane Douillet, Luca Guidoni, Jean-Pierre Likforman + Yajing Hao, Longzhao Liu, Xin Wang, Zhihao Han, Ming Wei, Zhiming Zheng, Shaoting Tang - Long-time evolution of density layers and interfaces in forced stably-stratified flows - https://arxiv.org/abs/2512.08714 - arXiv:2512.08714v1 Announce Type: new -Abstract: Stably stratified fluids subject to sustained forcing are known to develop step-like density "staircases", where nearly homogeneous layers alternate with thin interfaces of strong stratification. However, long-time numerical investigations of this phenomenon have been limited by the intrinsically slow evolution of large-scale modes and the sensitivity of stratified turbulence to physical parameters. We present direct numerical simulations of forced Boussinesq flows for three stratification strengths (Fr = 0.42, 0.22, 0.076) and of unprecedented time extensions - up to O(10000) turnover times - with the purpose of reproducing and studying the very slow coarsening of the layered state. A large-scale friction term is introduced to arrest shear-mode growth and mimic finite-domain constraints. Staircase formation is observed for both medium and strong stratified cases, following two different coarsening dynamics: interfaces decaying or merging. While kinetic energy remains quasi-stationary during interface decay, it exhibits sharp bursts during merging events. The emergence and persistence of density steps can be explained by the non-monotonic relation between buoyancy flux and buoyancy gradient. Intermittency in vertical velocity and density fluctuations is confined to the vicinity of layer-interface boundaries, indicating that strong events arise from the interaction between turbulent mixing and layer formation rather than from regions of large density gradients alone. - oai:arXiv.org:2512.08714v1 - physics.flu-dyn - Wed, 10 Dec 2025 00:00:00 -0500 + On the Frechet Root Kernel of Certain Wave Equations + https://arxiv.org/abs/2512.09609 + arXiv:2512.09609v1 Announce Type: new +Abstract: We extend the adjoint method to complex-valued PDEs and introduce the Fr\'echet root sensitivity kernel, as the most fundamental kernel from which all other material-sensitivity kernels can be derived. We apply this framework to four representative equations: two real-valued PDEs (the second-order wave equation and the Euler--Bernoulli beam equation) and two complex-valued PDEs (the complex transport equation and the Schroedinger equation with zero potential). We compute and analyze the Frechet root kernels for all four PDEs and show that, for constant material parameters, the kernel exhibits a consistent structure across systems, while its instantaneous form propagates as a wave whose shape depends on the initial conditions. For the Schroedinger equation, we find an especially notable result: the integrand of the Frechet root kernel coincides with the Born rule of quantum mechanics, suggesting that the probabilistic interpretation of the wavefunction may arise naturally from a general sensitivity-analysis framework rather than from an independent postulate. Our results establish a unified approach to sensitivity analysis for real- and complex-valued PDEs, provide a new perspective on the origin of the Born rule. + oai:arXiv.org:2512.09609v1 + physics.geo-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Niccolo Cocciaglia, Fabio Bonaccorso, Alessandra Sabina Lanotte, Luca Biferale + Rafael Abreu, Chahana Nagesh - Reducing dislocation defect levels via sub-melt nanosecond pulsed-laser induced densification of diamond - https://arxiv.org/abs/2512.08719 - arXiv:2512.08719v1 Announce Type: new -Abstract: Dislocations and polishing-induced defect networks in synthetic diamond generate local strain fields that broaden Raman features and limit optical, thermal, and electronic performance. Sub-melt laser annealing has emerged as a route to repair near-surface defects without graphitization, yet quantitative evidence of densification, defect depletion, and property recovery remains limited. Here, we show that nanosecond pulsed-laser annealing (PLA) can relax dislocation-associated strain in single-crystal CVD diamond by compacting and reorganizing the damaged near-surface region. Single- and two-pulse PLA were applied, and structural evolution was quantified using co-registered ISO 25178 white-light interferometry, depth-resolved Raman spectroscopy, and cross-sectional STEM with geometric phase analysis (GPA). Across a 5x6 grid(n = 30), responsive regions show large reductions in local slope (Sdq 45-65%), developed area (Sdr 60-90%), height spread (Sp, Sz 30-65%), void volume (Vv 57-60%), and roughness amplitude (Sa, Sq 48-57%), consistent with densification of ~4-6.5 nm. Raman profiling reveals narrowing of the diamond line and improved spectral uniformity to depths of ~2-3 {\mu}m, indicating relaxation of dislocation-mediated strain beyond the compaction layer. STEM-GPA strain maps confirm smoother strain fields, reduced hotspots, and redistribution of localized strain concentrations after PLA. These results show that sub-melt PLA reduces dislocation-driven strain by compacting surface-connected free volume and reorganizing defect networks. The approach provides a scalable path to upgrade industrial-grade diamond including homoepitaxial, heteroepitaxial, and polycrystalline CVD to low-defect, device-ready surfaces relevant to high-power electronics, photonics, and quantum substrates. - oai:arXiv.org:2512.08719v1 - physics.app-ph - cond-mat.mtrl-sci - Wed, 10 Dec 2025 00:00:00 -0500 + Rogue Vertical Drafts in the Mesosphere and Lower Thermosphere: Evidence and Implications + https://arxiv.org/abs/2512.09612 + arXiv:2512.09612v1 Announce Type: new +Abstract: Observational evidence of extreme vertical velocities (|w| ge 12.5 m/s and at times greater than 50 m/s) in the mesosphere and lower thermosphere (MLT), has emerged in recent years. We refer to these events as Rogue Vertical Drafts (RVDs). They exceed five standard deviations of observed vertical velocities and appear as paired updraft-downdraft structures in varicose mode. Four-dimensional observations reveal that RVDs are intermittent, recurrent, and unpredictable. On average, they are expected to occur every sim 12 days during summer over Northern Norway, assuming a 1000 s interval. Different instruments may capture only portions of these events, for example, only upward or downward drafts when restricted to a single altitude range. Despite their rarity, their magnitudes and frequency suggest potential impacts on dust-sized matter escaping from planets, natural and anthropogenic space material, and MLT climate and processes. We propose that RVDs are a fundamental yet under-recognized feature of the MLT, underscoring the need for global observations to assess their prevalence and significance. + oai:arXiv.org:2512.09612v1 + physics.ao-ph + astro-ph.EP + Thu, 11 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Adam H. Khan, Tae Sung Kim, Gabe Guss, Ted A. Laurence, Sonny S. Ly, Thejaswi U. Tumkur, Afaq H. Piracha + http://creativecommons.org/licenses/by/4.0/ + 10.3389/fspas.2025.1716224 + Frontiers in Astronomy and Space Sciences 2025 + J. L. Chau, A. Berera, D. Huyghebaert - Topological Braiding and Dynamic Probing of Phase Transitions at Temporal Interfaces in Non-Hermitian Synthetic Dimensions - https://arxiv.org/abs/2512.08736 - arXiv:2512.08736v1 Announce Type: new -Abstract: Non-Hermitian systems give rise to distinct topological phenomena, yet their manifestations at temporal interfaces characterized by abrupt changes in system parameters remain largely unex plored. Upon an abrupt alteration of the Hamiltonian in a one-dimensional non-Hermitian sys tem,the ensuring temporal interface excites both reflected and refracted wave modes. By intro ducing a chiral-symmetric Hamiltonian, this study reveals the topological effects at such temporal interfaces. We find that the reflection and refraction coefficients exhibit a topological braiding struc ture. This structure is directly determined by the difference in the topological invariants across the interface, establishing a bulk-boundary correspondence for temporal interfaces in non-Hermitian systems. Furthermore, we propose a dynamical probe that leverages the geometric similarity of eigenstates at the temporal interface to detect topological phase transitions. These findings estab lish a fundamental connection between topological braiding and nonreciprocal dynamics at temporal interfaces, providing a platform to explore phase transition detection and nonreciprocal phenomena in time-varying non-Hermitian systems. - oai:arXiv.org:2512.08736v1 + Conservation of transverse orbital angular momentum for spatiotemporal optical vortices + https://arxiv.org/abs/2512.09615 + arXiv:2512.09615v1 Announce Type: new +Abstract: The transverse orbital angular momentum (OAM) of spatiotemporal optical vortices (STOVs) has been a topic of active debate in recent years. Previous studies, relying on narrowband and paraxial approximations, resulted in unprecedented conclusions. Some researchers have proposed that electromagnetic waves require a modified definition of OAM to ensure conservation. In this work, we demonstrate that the transverse OAM of STOVs is highly sensitive to these commonly adopted approximations. Using the standard definition of OAM for electromagnetic waves, we demonstrate that the total transverse OAM is conserved during propagation once the narrowband and paraxial assumptions are removed. + oai:arXiv.org:2512.09615v1 physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Yuanhang Jiang, Jianfei Li, Chengxi Yang, Ziyi Liu, Chen Chen, Hongyu Liu, Zhongxiang Zhou, Jingfeng Yao, Chengxun Yuan + http://creativecommons.org/licenses/by/4.0/ + Jordan Adams, Youngbin Park, Andy Chong - Adaptive cut reveals multiscale complexity in networks - https://arxiv.org/abs/2512.08741 - arXiv:2512.08741v1 Announce Type: new -Abstract: Hierarchical clustering and community detection are important problems in machine learning and complex network analysis. A common approach to identify clusters is to simply cut dendrograms at some threshold. However, single-level cuts are often suboptimal in terms of capturing underlying structure in the data, especially when the dendrogram is unbalanced. In this paper, we present the adaptive cut, a novel method that leverages the hierarchical structure of dendrograms by employing multi-level cuts to overcome the limitations of single-level approaches. The adaptive cut optimizes an objective function using a Markov chain Monte Carlo with simulated annealing, resulting in better partitions. We demonstrate the effectiveness of the adaptive cut through applications to link clustering and modularity optimization, but note that the method is applicable to any clustering task that relies on a dendrogram and an objective function. Beyond the adaptive cut, we introduce the balancedness score, an information-theoretic metric that quantifies how balanced a dendrogram is. Balancedness predicts the potential benefits of using multi-level cuts. For the community detection examples, we evaluate our method on more than 200 real-world networks and multiple synthetic datasets, demonstrating significant improvements in partition density and modularity over traditional single-cut approaches. In addition, we show the generality of the adaptive cut by applying it across various hierarchical clustering techniques and objective functions. Our results indicate that the adaptive cut provides a robust and versatile tool for improving clustering outcomes. - oai:arXiv.org:2512.08741v1 - physics.soc-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Dark-State-Mediated Efficient Energy Trapping in a Model GFP Chromophore + https://arxiv.org/abs/2512.09637 + arXiv:2512.09637v1 Announce Type: new +Abstract: The functional properties of photoactive proteins are governed by the interplay between bright and dark excited states. While the bright states are well-studied, the dark states, which are fundamental to photostability and light harvesting, are notoriously difficult to characterize. Here, we report the direct observation and full characterization of an optically dark, low-lying singlet excited state in the isolated anion of the meta green fluorescent protein (GFP) chromophore. Using a combination of ultrafast time-resolved action-absorption and photoelectron spectroscopy, we have captured the formation of this state in 100 fs and measured its remarkably long lifetime of 94 ps. We unambiguously assign its charge-transfer character and reveal the precise trapping mechanism through high-level ab initio calculations. Our findings uncover a photoprotective mechanism in biomolecular anions where ultrafast internal conversion quenches electron emission, stabilizing long-lived electronic excitation even when the energy exceeds the electron detachment threshold. + oai:arXiv.org:2512.09637v1 + physics.chem-ph + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Louis Boucherie, Yong-Yeol Ahn, Sune Lehmann + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Elisabeth Gruber, Lars H. Andersen, Laurence H. Stanley, Jan R. R. Verlet, Ivan S. Avdonin, Anastasia V. Bochenkova - The new truly cylindrical tracker for the ALICE ITS3 - https://arxiv.org/abs/2512.08748 - arXiv:2512.08748v1 Announce Type: new -Abstract: The ALICE collaboration is preparing an upgrade of the three innermost layers of the current Inner Tracking System (ITS) during the next LHC long shutdown (LS3). The new ITS detector will use wafer-scale (up to \SI{27}{cm} in length) Monolithic Active Pixel Sensors with a \SI{65}{nm} CMOS Image Sensor process, thinned to \SI{50}{\micro m} and bent around the beam pipe. The planned upgrade will allow the use of only two sensors per tracker layer, kept in place by just two mechanical supports at the edges and two thin carbon fibre supports at the sensor border. The substitution of water cooling with air cooling will lead to an expected reduction of the material budget per-layer from $\sim$0.36\% $X_0$ of the current detector to 0.09\% $X_0$. The R\&D process also led to the development of a new sensor variant with an additional low dose n-type implant to the previous detector. This improves charge collection speed, confirms a spatial resolution of about \SI{5}{\micro m}, a detection efficiency greater than 99\% and an excellent radiation tolerance. Large area prototypes proved the possibility to have an active area greater than 90\%, and a fake hit rate lower than \SI{e-6}{hits/pixel/event} without loosing detection efficiency. This proceeding will show the above innovations, with particular attention to a small area analogue test structure featuring a front-end which can be monitored via an on-chip Operational Amplifier buffer that preserves the steep signal edge (few hundreds of ps) in order to study the sensor timing performance. The characterization proved a time resolution of \SI{63}{ps} on average and \SI{50}{ps} for signal passing right under the electrode with a detection efficiency above 99\%. - oai:arXiv.org:2512.08748v1 - physics.ins-det - Wed, 10 Dec 2025 00:00:00 -0500 + Time Served + https://arxiv.org/abs/2512.09647 + arXiv:2512.09647v1 Announce Type: new +Abstract: The following document provides a comprehensive look into the past, present, and future of Timing at Fermilab. By including historical context with technical implementation, this document seeks to help the reader gain a broader understanding of the facility and the mechanisms that enable the operation of Fermilab's accelerators + oai:arXiv.org:2512.09647v1 + physics.acc-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Stefania Perciballi (and on behalf of the ALICE Collaboration) + Evan Milton (Fermilab), Mark Austin (Fermilab), Dan McArthur (Fermilab) - Optimal navigation in two-dimensional regular and turbulent flows - https://arxiv.org/abs/2512.08766 - arXiv:2512.08766v1 Announce Type: new -Abstract: Zermelo's navigation problem seeks the trajectory of minimal travel time between two points in a fluid flow. We address this problem for an agent -- such as a micro-robot or active particle -- that is advected by a two-dimensional flow, self-propels at a fixed speed smaller than or comparable to the characteristic flow velocity, and can steer its direction. The flows considered span increasing levels of complexity, from steady solid-body rotation to the Taylor-Green flow and fully developed turbulence in the inverse cascade regime. Although optimal control theory provides time-minimizing trajectories, these solutions become unstable in chaotic regimes realized for complex background flows. To design robust navigation strategies under such conditions, we apply reinforcement learning. Both action-value (Q-learning) and policy-gradient (one-step actor-critic) methods achieve successful navigation with comparable performance. Crucially, we show that agents trained on coarse-grained flows -- retaining only large-scale features -- generalize effectively to the full turbulent field. This robustness to incomplete flow information is essential for practical navigation in real-world oceanic and atmospheric environments. - oai:arXiv.org:2512.08766v1 - physics.flu-dyn - Wed, 10 Dec 2025 00:00:00 -0500 + Surface Ion-Sound Wave in Magnetic Arch With High Pressure Plasma + https://arxiv.org/abs/2512.09686 + arXiv:2512.09686v1 Announce Type: new +Abstract: The work analytically substantiates the parameters of the surface wave found in numerical modelling of the collision of two oncoming supersonic plasma flows inside a magnetic arc in application to the experiment on the laboratory setup ``Solar Wind'' (Inst. Appl. Phys RAS). An ion-acoustic surface wave exists in the regime of dense plasma flows when their dynamic pressure is of the order of the pressure of an undisturbed magnetic field, so that the flows push the initial magnetic field out of their volume. The wave frequency is in the range between the ion gyrofrequencies inside the plasma bundle and in the outer region of the confining magnetic field. In the external rarefied medium, the near-surface structure is a heterogeneous magnetic sound, consistent in pressure and low total polarisation of the medium with the ``isotropic'' ion sound confined from the inside in a dense plasma bundle. The energy of the structure is mainly contained in the kinetic energy of the wave motion of ions inside the tube. At the same time, the electric field strength is sharply increased outside. Firstly, the latter circumstance arises from the need to maintain a uniform electron electric drift velocity inside the transition layer. Secondly, the energetically weak ion sound propagating into the outer environment is close to electrostatic ion oscillations below the ion gyrofrequency in the external region, which are characterised by increased electric field strength across the ambient magnetic field. + oai:arXiv.org:2512.09686v1 + physics.plasm-ph + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Vladimir Parfenyev + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Sergey A. Koryagin, Mikhail E. Viktorov, Artem V. Korzhimanov, Andrey A. Elyasin - Photonic electrometry using a piezoelectric-Pockels microresonator - https://arxiv.org/abs/2512.08773 - arXiv:2512.08773v1 Announce Type: new -Abstract: Facilitated by low-noise laser frequency locking, optical microresonators with the Pockels effect have shown unprecedented high resolutions in sensing electrical field. However, the requirement for tunable and low-noise laser sources considerably increases the cost and the size of the system, thereby limiting the industrial applicability of the microresonator-based technology. Here, we explore the possibility of using a low-cost fixed-frequency semiconductor laser as the pump laser to perform radiofrequency electrometry. A resonant mode in a lithium niobate microresonator is frequency-locked to the laser using the electrooptic effect. This same effect also underlies the radiofrequency electric-field sensing mechanism. Our experimental results show that the electrometry resolution can be maintained at signal frequencies beyond the optical resonance bandwidth and that the signal-to-noise ratio does not change with varied coupling conditions as long as the laser frequency noise is the dominant noise source of the system. In addition, narrowband electrooptic sensitivity enhancement is observed at frequencies of the microresonator's piezoelectric resonances, resulting in a resolution enhancement factor of approximately 3 at signal frequencies around 4 MHz. Our work advances the photonic resonant electrometry technology by studying the bandwidth limitation, and opens the road to the employment of low-cost lasers in high-resolution sensing applications. - oai:arXiv.org:2512.08773v1 + Self-Hybridized Exciton-Polariton Photodetectors From Layered Metal-Organic Chalcogenolates + https://arxiv.org/abs/2512.09691 + arXiv:2512.09691v1 Announce Type: new +Abstract: Exciton-polaritons (EPs) arising from strong light-matter coupling offer new pathways for controlling optoelectronic properties. While typically requiring closed optical cavities for strong coupling, we demonstrate that 2D metal-organic chalcogenolates (MOCs), mithrene (AgSePh), with a high refractive index (~2.5) and strong excitons enable self-hybridized polaritons photodetectors (PDs) without top mirrors, simplifying device architecture. Through thickness-tuned multimode polariton engineering, we achieve photodetection of sub-bandgap photons via lower polariton states, validated through reflectance, photoluminescence (PL), and photocurrent spectroscopy with quantitative theoretical agreement. Trap-assisted two-photon absorption enables sustained strong coupling even under sub-bandgap excitation. The polariton dispersion yields ultrafast group velocities (~65 {\mu}m/ps), extending exciton diffusion lengths from hundreds of nanometers to several micrometers. Strong-coupling devices demonstrate a 2.38-fold enhancement in photo-to-dark current ratio compared to weak-coupling counterparts, establishing a practical route to polariton-enhanced photodetection and light harvesting. + oai:arXiv.org:2512.09691v1 physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - 10.1103/6bkw-m89n - Suwan Sun, Hairun Guo, Andre Luiten, Wenle Weng + Bongjun Choi, Adam D. Alfieri, Wangleong Chen, Deep Jariwala - Injection dynamics in spin-wave active ring oscillator (SWARO) - https://arxiv.org/abs/2512.08796 - arXiv:2512.08796v1 Announce Type: new -Abstract: We investigated injection locking in spin-wave active ring oscillators (SWAROs) operating in the multi-mode regime. By applying external RF signals with varying frequency and power, we identified the locking behavior of individual modes and extracted the total locking ranges from spectral measurements. The results show asymmetric evolution of the lower and upper locking boundaries with drive power for the lower-frequency SWARO modes, while the highest-frequency mode exhibits nearly symmetric behavior. A maxi- mum locking range of over 11 MHz is observed at a drive power of -10 dBm. To interpret these results, we develop an Adler-like model that captures the dependence of the locking range on drive power, showing good agreement for the higher-frequency modes. For the lowest-frequency mode, however, the model underestimates the locking range at low drive and saturates at high drive power levels, while the experimental range increases mono- tonically, indicating the influence of multi-mode interactions. These findings establish SWARO as a useful platform for exploring injection phenomena in spin-wave ring systems with delayed feedback and motivate the development of extended injection models that account for multi-mode dynamics. - oai:arXiv.org:2512.08796v1 - physics.app-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Constraint-Free Coherent Diffraction Imaging via Physics-Guided Neural Fields + https://arxiv.org/abs/2512.09694 + arXiv:2512.09694v1 Announce Type: new +Abstract: CDI is a lensless imaging technique that enables atomic-resolution imaging of non-crystalline specimens and their dynamics. However, its broader implementation has been hindered by the instability and ill-posedness of its reconstruction process, known as phase retrieval, which relies heavily on handcrafted, object-specific constraints. To overcome the key limitations, we propose CDIP, a robust phase-retrieval framework that eliminates the need for such constraints by combining untrained coordinate-based neural fields for static and dynamic reconstructions and a physics-consistent forward model. We evaluate CDIP on simulated and experimental datasets that involve both static samples and dynamic processes, demonstrating that it substantially outperforms classical iterative algorithms and deep-learning baselines in terms of fidelity and stability. These results highlight a paradigm shift in both static and time-resolved CDI reconstruction, providing a broadly applicable framework for coherent imaging modalities such as ptychography and holography, across X-ray, electron, and optical probes. + oai:arXiv.org:2512.09694v1 + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Anirban Mukhopadhyay, Ihor I. Syvorotka, Anil Prabhakar + http://creativecommons.org/licenses/by/4.0/ + Zhe Hu, Zisheng Yao, Yuhe Zhang, Pablo Villanueva-Perez - CIEMAT-QI4X: a reactor-relevant quasi-isodynamic stellarator configuration compatible with an island divertor - https://arxiv.org/abs/2512.08825 - arXiv:2512.08825v1 Announce Type: new -Abstract: A four-field-period quasi-isodynamic stellarator configuration is presented that exhibits small neoclassical and electrostatic turbulent transport, good fast-ion confinement over a wide range of $\beta$ values, small bootstrap current and an edge island structure compatible with an island divertor. This configuration, called CIEMAT-QI4X, has been obtained by building on the optimization strategy and sophisticating the methods employed in [S\'anchez E. et al 2023 Nucl. Fusion 63 066037]. The optimization has been improved by incorporating metrics to control Mercier stability and by enforcing strict constraints on the rotational transform profile to achieve nested toroidal surfaces in the confinement region and a divertor island structure at the plasma edge. Specifically, CIEMAT-QI4X has a 4/4 island chain at the edge that is resilient at least up to $\beta=4\%$, even when the bootstrap current is included. A corresponding set of filamentary coils is presented that generates the configuration with enough accuracy to preserve the aforementioned physics properties. In terms of physics performance, CIEMAT-QI4X establishes as a candidate for a stellarator fusion reactor design. - oai:arXiv.org:2512.08825v1 - physics.plasm-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Structures resistant to Manipulation by all Wavefronts + https://arxiv.org/abs/2512.09696 + arXiv:2512.09696v1 Announce Type: new +Abstract: Using light to manipulate small particles is a tool with many practical applications throughout biophysics and nanotechnology. These tools have seen a significant increase in performance by utilizing shaped wavefronts, most commonly created with spatial light modulators. Wavefront shaping has also enabled the manipulation of seemingly arbitrary objects, which was impossible with conventional beams. In contrast, we show here the existence of a wide variety of objects that cannot be manipulated as desired, even with the optimal wavefront shaping protocol. The counterintuitive shapes of these objects are found using inverse design. Specifically, we show that the maximal pulling force is reduced by up to three orders of magnitude, and the maximal trapping stiffness is reduced by up to nearly two orders of magnitude. Our findings could prove useful in the development of micromachines that require a predictable mechanical reaction to an arbitrary wave. + oai:arXiv.org:2512.09696v1 + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - E. S\'anchez, J. L. Velasco, I. Calvo, J. M. Garc\'ia-Rega\~na, C. Salcuni, J. A. Alonso + http://creativecommons.org/licenses/by/4.0/ + Asher Sabbagh, Michael Horodynski, Rida Khan, Brian Shi, Marin Solja\v{c}i\'c - Near real-time channel selection for Distributed Acoustic Sensing technology - https://arxiv.org/abs/2512.08845 - arXiv:2512.08845v1 Announce Type: new -Abstract: Distributed Acoustic Sensing (DAS) technology is advancing seismic monitoring by providing dense observations near earthquake sources. However, the resulting data volumes often limit real-time processing capability, with most seismological applications focusing on retrospective analysis of seismic sequences. To address this challenge, we introduce ORION, a fast and versatile selector of high-quality DAS channels that efficiently reduces the amount of data to analyze. The method first adopts spatial clustering to identify cable segments with similar geometrical attributes (e.g, azimuth), and then performs channel selection within each section using waveform attributes (e.g., signal-to-noise ratio); this approach enables spatial sub-sampling while preserving azimuthal coverage. We demonstrate the flexibility of the selector across several cable geometries. Finally, we analyze a seismic sequence using ORION-selected channels and compare the source locations with those from a more conventional uniform distribution of channels along the cable, showing improvements in hypocenter accuracy. - oai:arXiv.org:2512.08845v1 - physics.geo-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Innovation ARIMA models application to predict pressure variations in water supply networks with open-loop control. Case study in Noja (Cantabria, Spain) + https://arxiv.org/abs/2512.09717 + arXiv:2512.09717v1 Announce Type: new +Abstract: Water utilities are increasingly concerned about losses, leaks, and illegal connections in their distribution networks. Pressure control is typically managed through pressure reducing valves with electrically controlled actuators based on predefined tables according to the pressure at the critical point control. This openloop control method lacks direct feedback between the PRV and CPC, making it challenging to distinguish whether pressure variations originate from normal head losses or abnormal network conditions. Unlike traditional applications of ARIMA focused on water demand forecasting, this study explores its novel use in pressure management within distribution networks, aiming to predict P3 pressure based on head losses across a defined hydraulic sector. To achieve this objective, a predictive model based on the Box-Jenkins methodology and its variations is implemented to analyse time series data. An action path is established to determine the optimal model ARIMA, ARMA, ARMAX, etc. which is subsequently validated using real operational data from Noja, a coastal town in northern Spain characterized by significant seasonal population fluctuations. By accurately forecasting CPC pressure, this system enhances the detection of anomalous patterns, enabling more efficient network pressure management. The study demonstrates the potential of advanced modelling techniques in optimizing water distribution networks, providing valuable insights to improve system efficiency, reliability, and sustainability in urban environments. + oai:arXiv.org:2512.09717v1 + physics.app-ph + stat.AP + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Emanuele Bozzi, Giulio Pascucci, Giacomo Rapagnani, Gian Maria Bocchini, Rebecca Harrington, Arantza Ugalde, Gilberto Saccorotti, Francesco Grigoli + 10.1016/j.nexus.2025.100423 + Energy Nexus 18 (2025) 100423 + David Munoz-Rodriguez, Manuel J. Gonzalez-Ortega, Maria-Jesus Aguilera-Urena, Andres Ortega-Ballesteros, Alberto-Jesus Perea-Moreno - Axial Symmetric Navier Stokes Equations and the Beltrami /anti Beltrami spectrum in view of Physics Informed Neural Networks - https://arxiv.org/abs/2512.08846 - arXiv:2512.08846v1 Announce Type: new -Abstract: In this paper, I further continue an investigation on Beltrami Flows began in 2015 with A. Sorin and amply reprised and developed in 2022 with M. Trigiante. Instead of a compact $3$-torus $T^3=\mathbb{R}^3/\Lambda$ where $\Lambda$ is a crystallographic lattice, as done in previous work, here I considered flows confined in a cylinder with identified opposite bases. In this topology I considered axial symmetric flows and found a complete basis of axial symmetric harmonic $1$-forms that, for each energy level, decomposes into six components: two Beltrami, two anti-Beltrami and two closed forms. These objects, that are written in terms of trigonometric and Bessel functions, constitute a function basis for an $L^2$ space of axial symmetric flows. I have presented a general scheme for the search of axial symmetric solutions of Navier Stokes equation by reducing the latter to an hierachy of quadratic relations on the development coefficients of the flow in the above described functional basis. It is proposed that the coefficients can be determined by means of a Physics Informed like Neural Network optimization recursive algorithm. Indeed the present paper provides the theoretical foundations for such a algorithmic construction that is planned for a future publication. - oai:arXiv.org:2512.08846v1 + Oceanic internal tides: do they get phased at the Equator? + https://arxiv.org/abs/2512.09728 + arXiv:2512.09728v1 Announce Type: new +Abstract: Low-mode baroclinic tides play a major role in ocean dynamics, especially for energy redistribution and deep ocean mixing. These internal waves, generated by tidal flow over submarine topography, can propagate for thousands of kilometres across ocean basins, and become unstable through wave-mean flow or wave-wave interactions. Satellite observations of internal tides have shown that part of their lunar semidiurnal (M2) altimetry signal loses phase coherence in equatorial regions, thus affecting how we interpret their dynamics and energy distribution (Buijsman et al. 2017). We investigate the interaction of a baroclinic M2 internal tide wavepacket with an equatorial zonal jet, possibly of any horizontal or vertical structure. The dynamics of the low modes are explored as well as the potential excitation of higher vertical modes and how these interactions can generate incoherences in the baroclinic tide signal. + We develop an idealized linear model using modal decomposition (Kelly et al. 2016), which is solved using Dedalus, to study the dynamics of a mode 1 M2 internal wavepacket on an equatorial beta plane. A zonal jet, with a uniform or a sheared vertical structure, is added at the equator to investigate potential wave-mean flow interaction. We find that a vertically uniform zonal jet affects the propagation of the mode 1 wavepacket. Depending on the strength of the jet, this can cause total reflection or strong distortion of the wavepacket. In contrast, a wavepacket entering a vertically sheared jet shows energy scattering into higher modes, which have lower phase and group speeds, shorter wavelengths, and are thus more susceptible to dissipation (and critical layers for non-uniform stratification). As the wavepacket exits the jet, reverse energy transfer occurs and the phase speed difference between the modes may explain part of the phase incoherence observed in altimetry data. + oai:arXiv.org:2512.09728v1 + physics.ao-ph + astro-ph.EP physics.flu-dyn - cs.IT - math-ph - math.IT - math.MP - math.OC - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Pietro Fr\'e + Camille Moisset, Bruce Sutherland, Lois Baker - Cultural evolution of human beauty standards - https://arxiv.org/abs/2512.08861 - arXiv:2512.08861v1 Announce Type: new -Abstract: Beauty standards shape self-perception and health through social comparison and objectification, while exposure to idealized imagery exacerbates body-image concerns. Media and fashion are central arbiters of these ideals, yet long-term, quantitative, intersectional studies on how representation has changed remain scarce. We assembled a dataset of 793199 records spanning 25 years of advertising, magazine covers, runway shows, and editorials to quantify changes in anthropometric and demographic representation. We find a paradox in the evolution of beauty ideals: while representational diversity has increased, the median model physique remains stable. This is driven by selective plus-size inclusion at the upper tail, while the typical physique continues to diverge from the US population. Intersectionally, non-white models are 4.5 times more likely to be plus-size, indicating that progress in size inclusivity falls disproportionately on multiple underrepresented identities. Stratifying the industry via a data-driven prestige hierarchy, we find that thinness is overrepresented at the top tier. Finally, comparing two regulatory interventions we observe that numeric thresholds are more effective at reducing underweight appearances. Our results quantify the cultural evolution in media and fashion, revealing that inclusion has increased; however, gains are uneven and intersectionally concentrated on size and ethnicity, whereas the prevailing thin ideal remains largely unchanged. - oai:arXiv.org:2512.08861v1 - physics.soc-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Mode Control and Dynamic Population Gratings in Quantum-Dot Lasers + https://arxiv.org/abs/2512.09740 + arXiv:2512.09740v1 Announce Type: new +Abstract: Single-mode operation is essential for integrated semiconductor lasers, yet most solutions rely on regrowth, etched gratings, or other complex fabrication steps that limit scalability. We show that quantum-dot (QD) lasers can achieve stable single-mode lasing through a simple cavity design using dynamic population gratings (DPGs). Owing to the low lateral carrier diffusion of QDs, a strong standing-wave-induced carrier grating forms in a reverse-biased saturable absorber and provides self-aligned, mode-selective feedback not attainable in quantum-well devices. A single-ring laser achieves 46 dB side-mode suppression ratio (SMSR), while a dual-ring Vernier laser delivers ($>$ 46 nm) tuning range and up to 52.6 dB SMSR, with continuous-wave operation up to $80\,^{\circ}\mathrm{C}$. The laser remains single-mode under $-10.6$ dB external optical feedback and supports isolator-free data transmission at 32 Gbps. These results establish DPG-enabled QD lasers as a simple and scalable route to tunable, feedback-resilient on-chip light sources for communication, sensing, and reconfigurable photonic systems. + oai:arXiv.org:2512.09740v1 + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Xiangpeng Ou, Artem Prokoshin, Hongyan Yu, Xin Yao, Ying Shi, William He, Zhican Zhou, Yating Wan + + + Machine Learning Optimization of BEGe Detector Event Selection in the VIP Experiment + https://arxiv.org/abs/2512.09777 + arXiv:2512.09777v1 Announce Type: new +Abstract: The VIP collaboration operates a Broad Energy Germanium detector at the Gran Sasso National Laboratory to measure radiation in the few keV to 100 keV range, aiming to search for spontaneous collapse induced radiation and atomic transitions that violate the Pauli Exclusion Principle. Here we present a machine learning based upgrade for the BEGe detector using an event selection strategy aimed at improving the efficiency in detecting low energy events down to 10 keV. The method employs a denoising autoencoder to suppress electronic and microphonic noises and to reconstruct pulse shapes, followed by a convolutional neural network that classifies waveforms as normal single site or events with anomalies. The workflow was validated on a dataset comprising more than 20000 waveforms recorded in 2021. The classifier achieves a receiver operating characteristic curve with an area under the curve of 0.99 and an accuracy of 95 percent. Applying this procedure lowers the minimum detectable energy of the final spectrum to approximately 10 keV. It also yields a measurable enhancement in spectral quality, including an improvement of about 14 percent in the signal to background ratio and a reduction of the energy resolution for the characteristic Pb and Bi gamma lines. These developments enhance the sensitivity of the BEGe detector to rare low energy signals and provide a scalable framework for future precision tests of quantum foundations in low background environments. + oai:arXiv.org:2512.09777v1 + physics.ins-det + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Louis Boucherie, Sagar Kumar, Katharina Ledebur, August Lohse, Karolina Sliwa + Simone Manti, Jason Yip, Massimiliano Bazzi, Nicola Bortolotti, Mario Bragadireanu, Ivan Carnevali, Alberto Clozza, Luca De Paolis, Raffaele Del Grande, Carlo Guaraldo, Mihai Antoniu Iliescu, Matthias Laubenstein, Johan Marton, Fabrizio Napolitano, Federico Nola, Kristian Pischicchia, Alessio Porcelli, Alessandro Scordo, Francesco Sgaramella, Diana Sirghi, Florin Sirghi, Johann Zmeskal, Catalina Curceanu - Spreading processes on heterogeneous active systems: spreading threshold, immunization strategies, and vaccination noise - https://arxiv.org/abs/2512.08878 - arXiv:2512.08878v1 Announce Type: new -Abstract: We study spreading processes in two-dimensional systems of heterogeneous active agents that exhibit different individual active speeds. We obtain, combining kinetic and complex network theory, an analytical expression for the spreading threshold that depends not only on the first but also second moment of the speed distribution. Moreover, we prove that spreading can even occur for vanishing average active speed. Furthermore, we find that random vaccination strategies are ineffective in heterogeneous active systems, whereas targeted ones are effective. We also show that vaccination acts as (quenched) noise: it can decrease or increase the outbreak size. Our results offer insights into how information propagates in heterogeneous populations of active agents. - oai:arXiv.org:2512.08878v1 - physics.bio-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Lessons from pendulums: A design comparison of three lab activities + https://arxiv.org/abs/2512.09781 + arXiv:2512.09781v1 Announce Type: new +Abstract: We present three versions of a pendulum lab activity and explore how shared theoretical commitments, motivations, and aspirations can lead to divergences in curriculum design. Building on Boudreaux & Elby (2020) we provide another demonstration of how theoretical commitments and perspectives influence curriculum development. In this paper, the variations across these lab activities despite our shared theoretical bases constitutes the phenomena of interest. We argue that three main factors lead to the variations in our design decisions: different expectations and understandings of our student populations, variations in our ancillary pedagogical goals, and fine grained differences in our theoretical perspectives. By focusing on the differences between our labs, we highlight the limitations of theory alone to determine curriculum development and demonstrate the process of theory, in conversation with local particularities, guiding design. + oai:arXiv.org:2512.09781v1 + physics.ed-ph + Thu, 11 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Benjam\'in Marcolongo, Gustavo J. Sibona, Fernando Peruani + http://creativecommons.org/licenses/by/4.0/ + Ian Descamps, Roger Tobin, Paul Wagoner, David Hammer, N. G. Holmes, Rachel E. Scherr - Dual-wavelength Fourier Ptychographic Topography - https://arxiv.org/abs/2512.08883 - arXiv:2512.08883v1 Announce Type: new -Abstract: We introduce a dual-wavelength Fourier ptychographic topography (FPT) method that extends the lambda/2 height-range limit of single-wavelength FPT. By reconstructing complex fields at two illumination wavelengths and exploiting their phase difference, the method achieves an effective synthetic wavelength lambda_s and an unambiguous range of lambda_s/2 without reducing lateral resolution. A noise-robust wrapped-number search is used to select per-pixel integer pairs (k1, k2), and a global refinement with circular TV regularization and soft bounds improves stability and preserves height discontinuities. The approach is validated through rigorous scattering-model-based simulations and experiments on structured silicon samples, demonstrating accurate height recovery in regimes where single-wavelength FPT exhibits phase wrapping. We analyze the limits of the FPT forward model and identify aspect ratio (AR) and phase modulation transfer function (ph-MTF) as key predictors of reconstruction fidelity. Simulations and experiments show that increasing AR beyond a practical threshold causes loss of high-frequency phase transfer and destabilizes dual-wavelength unwrapping. Within this AR range, dual-wavelength FPT provides robust, high-resolution topography suitable for semiconductor and industrial metrology. - oai:arXiv.org:2512.08883v1 - physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + Time-dependent ab__initio molecular-orbital decomposition for high-harmonic generation spectroscopy + https://arxiv.org/abs/2512.09793 + arXiv:2512.09793v1 Announce Type: new +Abstract: We propose a real-time time-dependent ab__initio approach within a configuration-interaction-singles ansatz to decompose the high-harmonic generation (HHG) signal of molecules in terms of individual molecular-orbital (MO) contributions. Calculations have been performed by propagating the time-dependent Schr{\"o}dinger equation with complex energies, in order to account for ionization of the system, and by using tailored Gaussian basis sets for high-energy and continuum states. We have studied the strong-field electron dynamics and the HHG spectra in aligned CO2 and H2O molecules. Contribution from MOs in the strong-field dynamics depends on the interplay between the MO ionization energy and the coupling between the MO and the laser-pulse symmetries. Such contributions characterize different portions of the HHG spectrum, indicating that the orbital decomposition encodes nontrivial information on the modulation of the strong-field dynamics. Our results correctly reproduce the MO contributions to HHG for CO2 as described in the literature experimental and theoretical data and lead to an original analysis of the role of the highest occupied molecular orbitals HOMO, HOMO-1, and HOMO-2 of H2O according to the polarization direction of the laser pulse. + oai:arXiv.org:2512.09793v1 + physics.chem-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Yi Shen, Tongyu Li, Hao Wang, Jinyong Kim, Hojun Lee, Wookrae Kim, Jonghyeok Park, Junho Shin, Seungbeam Park, Lei Tian + The Journal of Chemical Physics, 2024, 161 (20), pp.204111 + Marco Marchetta (LCT), Chiara Morassut (LCT), Julien Toulouse (LCT, IUF), Emanuele Coccia (LCT), Eleonora Luppi (LCT) - A microstructural rheological model for transient creep in polycrystalline ice - https://arxiv.org/abs/2512.08907 - arXiv:2512.08907v1 Announce Type: new -Abstract: The slow creep of glacial ice plays a key role in sea-level rise, yet its transient deformation remains poorly understood. Glen's flow law, where strain rate is simply a function of stress, cannot predict the time-dependent creep behavior observed in experiments. Here we present a physics-based rheological model that captures all three regimes of transient creep in polycrystalline ice. The key components of the model are a series of Kelvin-Voigt mechanical elements that produce a power-law (Andrade) creep, and a single viscous element with microstructure and stress dependence that represents reorientation in the polycrystalline grains. The interplay between these components produces a minimum in the strain rate at approximately 1% strain, which is a universal but unexplained feature reported in experiments. Due to its transient nature, the model exhibits fractional power-law exponents in the stress dependence of the strain rate minimum, which has been conventionally interpreted as independent physical processes. Taken together, we provide a compact, mechanistic framework for transient ice rheology that generalizes to other polycrystalline materials and can be integrated into constitutive laws for ice-sheet models. - oai:arXiv.org:2512.08907v1 - physics.geo-ph - cond-mat.soft - Wed, 10 Dec 2025 00:00:00 -0500 + Frequency-Dependent Polarization Propagator Calculation for Quantum Dots Using Optimized Inverse Krylov Subspace and Folded-Spectrum Method + https://arxiv.org/abs/2512.09811 + arXiv:2512.09811v1 Announce Type: new +Abstract: Accurate prediction of the frequency response of quantum dots under electromagnetic radiation is essential for investigating absorption spectra, excitonic effects, and nonlinear optical behavior in quantum dots and semiconductor nanoparticles. The polarization propagator provides a rigorous framework for evaluating these properties, but its construction is computationally demanding. Challenges arise from the level of electron correlation, the size of the excitonic basis, and the cost of evaluating two-electron integrals. This work addresses these difficulties by developing first- and second-order frequency-dependent polarization propagator calculations for PbS and CdS quantum dots. The propagator is formulated using the electron propagator approach and expressed as the resolvent of the Hamiltonian superoperator. Light-matter interaction is treated using the dipole approximation and represented in a particle-hole excitation operator basis. The correlated ground state is treated at the MP2 level, and all response-matrix terms up to second order in the fluctuating potential are included. A frequency-dependent inverse Krylov subspace method is derived and combined with the folded-spectrum technique to isolate excitation energies within a chosen frequency window. This strategy avoids full diagonalization of the response matrix and significantly reduces computational cost for large systems. The method is implemented in a matrix-free manner in which no explicit response matrix is assembled, and all operations rely on matrix-vector products. UV-VIS excitation spectra of PbS and CdS quantum dots were computed, demonstrating that the inverse Krylov subspace projection approach provides an efficient and accurate approximation for excitation spectra when full diagonalization is computationally prohibitive. + oai:arXiv.org:2512.09811v1 + physics.chem-ph + cond-mat.mes-hall + physics.atm-clus + physics.comp-ph + Thu, 11 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Alex J. Vargas, Ranjiangshang Ran, Justin C. Burton + Chandler Martin, Nicole Spanedda, Anaira Jalan, Emily Schafer, Jessica Beyer, Arindam Chakraborty - Effect of the Gradient of the Spin-Polarization in Density Functional Approximations - https://arxiv.org/abs/2512.08913 - arXiv:2512.08913v1 Announce Type: new -Abstract: The construction of non-empirical density functional approximations is typically guided by the satisfaction of exact constraints. An important constraint is the recovery of the gradient expansion for slowly varying electron densities. In prior constructions of semilocal density functional approximations, the $\nabla \zeta$-dependent terms in the gradient expansion of the correlation have been dropped, where $\zeta$ is the relative spin polarization. We propose a scheme by which such terms can be reintroduced into already constructed functionals without significantly affecting other constraints and norms. We implement this scheme on the Strongly Constrained and Appropriately Normed (SCAN) functional to construct a $\nabla \zeta$-corrected version of SCAN. The resulting functional is shown to provide improvements in transition-metal atoms and molecules without significantly affecting SCAN's accurate description of $sp$-systems. For the binding energy curve of the chromium dimer Cr$_2$, the SCAN underbinding is fully corected at large bond lengths and reduced at short bond lengths. - oai:arXiv.org:2512.08913v1 - physics.chem-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Density of hybrid plasma generated by microwave and laser radiation in the Ar:H2:CH4 mixture + https://arxiv.org/abs/2512.09816 + arXiv:2512.09816v1 Announce Type: new +Abstract: The atmospheric-pressure hybrid plasma in the Ar:H2:CH4 mixture, maintained by microwave radiation (2.47 GHz) and CO2 laser radiation (10.6 {\mu}m) in the chamber of an experimental plasma-chemical reactor designed to study the synthesis of diamond-like coatings was studied. The electron number density was determined from the Stark broadening of the H{\alpha} line shape of atomic hydrogen. It was shown that when laser radiation is focused in the region of a microwave plasma bunch, the H{\alpha} line shape in the hybrid plasma spectra has broad wings and is described by a Lorentz function with a two-contour approximation. The complex structure of the H{\alpha} line profile of the hybrid plasma indicates its spatiotemporal inhomogeneity. The electron number density corresponding to the contour with a smaller half-width exceeds the electron number density in microwave plasma and lies in the range of (4-8)E15 cm-3, and the electron number density measured by the contour with a larger half-width is (1.5-2)E17 cm-3. + oai:arXiv.org:2512.09816v1 + physics.plasm-ph + Thu, 11 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Rohan Maniar, John P. Perdew + http://creativecommons.org/licenses/by/4.0/ + S. V. Avtaeva (Institute of Laser Physics SB RAS, Novosibirsk, Russia, Novosibirsk State Technical University, Novosibirsk, Russia), V. B. Dolomanova (Institute of Laser Physics SB RAS, Novosibirsk, Russia, Novosibirsk State Technical University, Novosibirsk, Russia), P. A. Pinaev (Institute of Laser Physics SB RAS, Novosibirsk, Russia), A. E. Medvedev (Institute of Laser Physics SB RAS, Novosibirsk, Russia) - Strong Mode Coupling via Quasi-Bound States in the Continuum in Bianisotropic Metasurfaces - https://arxiv.org/abs/2512.08927 - arXiv:2512.08927v1 Announce Type: new -Abstract: Electromagnetic mode coupling plays a key role in many resonant effects in nanophotonics. This coupling is also responsible for the appearance of bianisotropy, where electric and magnetic responses become interconnected through the interaction of their respective modes. In this work, we develop a simple and general temporal coupled-mode theory model to describe off-diagonal chiral bianisotropy. Using quasi-bound states in the continuum (q-BICs), we demonstrate how to control the hybridization of modes with opposite symmetries, resulting in Rabi-like splitting between the hybrid states in the regime of strong electromagnetic mode coupling. Beyond revealing the physical origin of the hybrid modes, our model predicts and explains the emergence of dual-band asymmetric reflection and absorption, and how to achieve maximum directional absorption difference. The theoretical predictions are verified by full-wave simulations, showing very good agreement with theory. Furthermore, very strong reciprocal bianisotropy is demonstrated with the use of q-BICs in a deeply subwavelength metasurface in the optical frequency range. Our results provide a clear physical picture of the interaction process between modes, offering a compact theoretical framework for understanding and designing bianisotropic dielectric metasurfaces not only in the traditional regime but also in the strong coupling regime. - oai:arXiv.org:2512.08927v1 - physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + Scintillation response of cryogenic CsI to few-keV and sub-keV nuclear recoils + https://arxiv.org/abs/2512.09820 + arXiv:2512.09820v1 Announce Type: new +Abstract: Monochromatic neutron emissions from photonuclear sources $^{88}$Y/Be and $^{124}$Sb/Be are employed to obtain the response of pure (undoped) cesium iodide at 80 K. The use of a low-noise, high-quantum-efficiency avalanche photodiode in combination with a novel waveshifter results in a 70 eV analysis threshold. This reach allows to observe signals from sub-keV nuclear recoils originating in neutron scattering. The extracted quenching factor drops much faster towards low energy than the extrapolation of a model developed for room-temperature CsI[Na]. We comment on the impact of our measurement on planned use of cryogenic CsI in neutrino physics and dark matter experiments. + oai:arXiv.org:2512.09820v1 + physics.ins-det + hep-ex + hep-ph + nucl-ex + Thu, 11 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Luis Manuel M\'a\~nez-Espina, Bahman Amrahi, Viktar Asadchy, Ana D\'iaz-Rubio + J. I. Collar, C. M. Lewis, A. Sim\'on, S. G. Yoon - Icy worlds: Moons and Dwarf Planets - https://arxiv.org/abs/2511.18776 - arXiv:2511.18776v1 Announce Type: cross -Abstract: In the outer solar system beyond Jupiter, water ice is a dominant component of planetary bodies, and most solid objects in this region are classified as icy bodies. Icy bodies display a remarkable diversity of geological, geophysical, and atmospheric processes, which differ fundamentally from those of the rocky terrestrial planets. Evidence from past and ongoing spacecraft missions has revealed subsurface oceans, cryovolcanic activity, and tenuous but persistent atmospheres, showing that icy bodies are active and evolving worlds. At the same time, major questions remain unresolved, including the chemical properties of icy materials, the geological histories of their surfaces, and the coupling between internal evolution and orbital dynamics. Current knowledge of the surfaces, interiors, and atmospheres of the principal icy bodies is built on spacecraft measurements, telescopic observations, laboratory experiments, and theoretical modeling. Recent contributions from Juno, JWST, and stellar occultation studies have added valuable constraints on atmospheric composition, interior structure, and surface activity. Looking ahead, missions such as JUICE, Europa Clipper, Dragonfly, and the Uranus Orbiter and Probe are expected to deliver substantial progress in the study of icy bodies. Their findings, combined with continued Earth- and space-based observations and laboratory studies, will be critical for assessing the potential habitability of these environments and for placing them within a broader framework of planetary system formation and evolution. - oai:arXiv.org:2511.18776v1 - astro-ph.EP - physics.geo-ph - Wed, 10 Dec 2025 00:00:00 -0500 - cross - http://creativecommons.org/licenses/by/4.0/ - 10.1093/acrefore/9780190647926.013.87 - Jun Kimura + Damped Kinetic Alfv\'en Waves in Earth's Magnetosheath: Numerical Simulations and MMS Observations + https://arxiv.org/abs/2512.09828 + arXiv:2512.09828v1 Announce Type: new +Abstract: The Earth's magnetosheath provides a high $\beta$ (ratio of electron thermal pressure to magnetic pressure) plasma environment where kinetic Alfv\'en waves (KAWs) strongly influence turbulence and energy dissipation. This study investigates how Landau damping modifies the nonlinear evolution of KAWs by solving a modified nonlinear Schr\"odinger equation that captures both dispersive and nonlinear effects. Without Landau damping, modulational instability drives rapid self-focusing into intense magnetic filaments, producing a turbulent cascade with $k_\perp^{-5/3}$ scaling in the inertial range ($k_\perp\rho_i<1$) that transitions to $k_\perp^{-8/3}$ at sub-ion scales ($k_\perp\rho_i>1$), here $k_\perp$ is the wavevector component perpendicular to the background magnetic field and $\rho_i$ the ion thermal gyroradius. When Landau damping is included, magnetic structures are significantly suppressed, and the spectrum steepens to $k_\perp^{-11/3}$ in the sub-ion range while the inertial range maintains $k_\perp^{-5/3}$ scaling. The damping acts across all scales through resonant wave-particle interactions, efficiently transferring energy from waves to particles. Direct comparison with Magnetospheric Multiscale (MMS) spacecraft observations shows that the observed kinetic range spectral slope falls between our undamped and damped simulation limits, consistent with an intermediate damping regime in magnetosheath turbulence. This agreement confirms that Landau damping is one of the primary mechanisms controlling turbulent energy dissipation at kinetic scales in collisionless plasmas. + oai:arXiv.org:2512.09828v1 + physics.plasm-ph + physics.space-ph + Thu, 11 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Mani K. Chettri, Hemam D. Singh, Vivek Shrivastav, Britan Singh, Rupak Mukherjee - Effective Field Theory Perspective On King Non-linearity - https://arxiv.org/abs/2512.03157 - arXiv:2512.03157v1 Announce Type: cross -Abstract: Precision spectroscopic measurements of isotope shifts have recently reached a high level of accuracy. Tests of King non-linearity (NL) along isotope chains have been proposed as a tool to search for fifth-force mediators. At the same time, these tests can potentially teach us about the structure of heavy nuclei at unprecedented precision, where King NL has already been observed in several systems. A robust interpretation of the existing data, however, is hampered by incomplete control over the Standard Model (SM) contributions. We develop a systematic effective field theory framework, matching the SM onto scalar non-relativistic QED in the infinite nuclear mass limit and then onto quantum-mechanical potentials. This approach organizes all nuclear effects into a small set of Wilson coefficients and cleanly separates short- and long-distance physics. We show that the commonly used treatment of the $\langle r^2\rangle^2$ term needs to be reconsidered, as it arises only at second-order in perturbation theory, and we derive the long-range $1/r^4$ potential from nuclear polarizability. Applying the framework to hydrogen-like systems, we provide a transparent classification of SM sources of King NL relevant for current and future isotope-shift experiments. The formalism can be applied to learn about the shape of the heavy scalar nuclei at a higher level of precision and detail than what was previously attainable. - oai:arXiv.org:2512.03157v1 - hep-ph - nucl-th - physics.atom-ph - Wed, 10 Dec 2025 00:00:00 -0500 - cross - http://creativecommons.org/licenses/by/4.0/ - Beno\^it Assi, Sam Carey, Sebastian J\"ager, Gabriel Lee, Gil Paz, Gilad Perez, Jure Zupan + Comparison of time-resolved photoluminescence and deep-level transient spectroscopy defect evaluations in an InAs nBn detector subjected to in-situ and ex-situ 63 MeV proton irradiation + https://arxiv.org/abs/2512.09837 + arXiv:2512.09837v1 Announce Type: new +Abstract: Deep-level transient spectroscopy and temperature-dependent time-resolved photoluminescence experiments are performed on identical InAs nBn photodetector structures as a function of in-situ and ex-situ 63 MeV proton irradiation to assess their generation and recombination dynamics. Pre-irradiation, the n-type InAs absorbing region exhibits a steadily increasing minority carrier lifetime with increasing temperature, providing evidence that excited minority carriers may be recombining via shallow defect levels. From deep-level transient spectroscopy, two features are found between 10 K and 275 K: a low temperature broad shoulder, which suggests emission from multiple shallow electron defect levels with energies < 29 meV, and a high temperature minimum occurring at approximately 230 K with an activation energy of 539 meV, which suggests a defect in the barrier layer in the device. Two similar nBn detectors are then subjected to 63 MeV proton irradiation in step doses and measured between steps. One experiment is performed in-situ with an nBn held at approximately 10 K during dosing, and the other experiment is performed ex-situ with a similar nBn held at room temperature for dosing. The ex-situ dosing results in an evaluation of the defect introduction rate that is 3-4x lower than in-situ due to partial annealing of the proton-induced displacement damage at room temperature. The results for these two experiments are then compared with the dose-dependent recombination rate analysis, resulting in an estimated recombination defect cross-section of 1.6x10^(-14) cm^2 for the shallow shoulder defect. + oai:arXiv.org:2512.09837v1 + physics.app-ph + Thu, 11 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Rigo A. Carrasco, Christopher P. Hains, Nathan Gajowski, Alexander T. Newell, Julie V. Logan, Zinah M. Alsaad, Preston T. Webster, Christian P. Morath, Diana Maestas, Aaron J. Muhowski, Samuel D. Hawkins, Evan M. Anderson - Thermal stability originates the vanishing of the specific heats at the absolute zero - https://arxiv.org/abs/2512.05129 - arXiv:2512.05129v2 Announce Type: cross -Abstract: The relationship between the vanishing of the heat capacities as $T\to0^+$ and the thermal stability is examined. The heat capacities vanish as fast as or faster than $T$ as $T\to0^+$ for states at the phase space boundary ($T=0$) to sustain the standard thermal stability criterion $U_{ss}>0$. Conversely, weakly vanishing heat capacities, which signify a loss of curvature in $U(S)$ at $T=0$, are the signature of a critical condition precisely at $T=0$, as exemplified in marginal Fermi liquids. Therefore, the vanishing of the specific heat should be viewed not as a new law but as a confirmatory result of the existing framework of thermodynamics. - oai:arXiv.org:2512.05129v2 - cond-mat.stat-mech - cond-mat.str-el - physics.chem-ph - physics.class-ph - physics.hist-ph - Wed, 10 Dec 2025 00:00:00 -0500 - cross + Perspectives of Women and Men Students and Faculty on Conceptual and Quantitative Problem-Solving in Physics from Introductory to Graduate Levels + https://arxiv.org/abs/2512.09843 + arXiv:2512.09843v1 Announce Type: new +Abstract: Developing expertise in physics requires appropriate integration and assimilation of physics and mathematics. Instructors and students often describe physics courses in terms of their emphasis on conceptual and quantitative problem-solving. For example, they may argue that a course emphasizes primarily conceptual over quantitative problem-solving or may emphasize equally on both depending on instructional context and assessment design. In this study, we investigated how students and instructors across different levels of physics instruction perceive the roles and development of conceptual and quantitative problem-solving in student learning and expertise development. Using departmental surveys administered at the beginning and end of each semester, we collected both Likert-scale and open-ended responses from students enrolled in introductory, upper-level undergraduate and graduate physics courses. These surveys assessed students' self-perceived skills, preferences and perceptions of instrucots and course emphasis. To complement student perspectives, we conducted interviews with instructors using parallel questions adapted to reflect instructional goals and expectations. Our findings highlight patterns in how students and instructos prioritize conceptual and quantitative problem-solving across course levels, as well as alignment and misalignment between student and instructor perspectives. + oai:arXiv.org:2512.09843v1 + physics.ed-ph + Thu, 11 Dec 2025 00:00:00 -0500 + new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1088/1402-4896/ae22a5 - Physica Scripta 2025 100 125206 - Mart\'in-Olalla, Jos\'e Mar\'ia + 10.3390/educsci15121602 + Education Sciences 2025, 15(12), 1602 + Apekshya Ghimire, Chandralekha Singh - Numerical Algebraic Geometry for Energy Computations on Tensor Train Varieties - https://arxiv.org/abs/2512.06939 - arXiv:2512.06939v1 Announce Type: cross -Abstract: We study energy minimization problems in quantum chemistry through the lens of computational algebraic geometry. We focus on minimizing the Rayleigh quotient of a Hamiltonian over a tensor train variety. The complex critical points of this problem approximate eigenstates of the quantum system, with the global minimum approximating the ground state. We call the number of critical points the Rayleigh-Ritz degree. - After introducing tensor train varieties, we identify instances when they are Segre products of projective spaces. We also report what we know about the defining ideals of tensor trains. We present a birational parametrization of them from products of Grassmannians. Along the way, we study the Rayleigh-Ritz degree, and we introduce the Rayleigh-Ritz discriminant, which describes Hamiltonians that lead to deficient number of critical points. We use homotopy continuation to compute all critical points of this optimization problem over various tensor train and determinantal varieties. Finally, we use these results to benchmark state-of-the-art methods, the Alternating Linear Scheme and Density Matrix Renormalization Group. - oai:arXiv.org:2512.06939v1 - math.AG - math.OC - physics.chem-ph - Wed, 10 Dec 2025 00:00:00 -0500 - cross + Noise dynamics in large mode volume Brillouin lasers + https://arxiv.org/abs/2512.09855 + arXiv:2512.09855v1 Announce Type: new +Abstract: Photonic integrated Brillouin lasers have emerged as an important tool to realize a wide range of precision applications, including atomic time-keeping, low-noise microwave signal generation, fiber and quantum sensing, and ultra-high capacity coherent communications. While Brillouin lasers routinely achieve sub-Hz instantaneous linewidths, many of these applications also require exceptional frequency stability and high-power single-mode emission. A recent demonstration showed that extending the resonator length increases the laser power while also improving the frequency stability through suppression of thermorefractive noise. However, as the resonator scales to larger lengths, multiple optical resonances can be found within the Brillouin gain bandwidth, greatly complicating the laser dynamics compared to existing coupled-mode Brillouin laser models. Given the potential to scale lasers of this type to watt-level output powers at sub-mHz linewidths, a theoretical model describing this physics is needed to provide key insights into their performance. Here, we develop a coupled-mode theory of integrated large mode volume Brillouin lasers, accounting for multiple cavity modes with potential to lase within the gain bandwidth. We obtain expressions for the steady-state dynamics, spontaneous spectrum, relative intensity noise, and frequency noise. Our analysis reveals that the broad gain bandwidth results in atypical Brillouin dynamics, giving rise to distinct features in the noise spectra, and consequently modifications of the standard, single-mode fundamental linewidth of Brillouin lasers. Additionally, these features may be used for a variety of tangential applications, such as phonon spectroscopy or quality factor enhancement. Furthermore, we find that the linewidth can be significantly impacted by transferred RIN from the external pump in Brillouin lasers that lack ideal phase matching. + oai:arXiv.org:2512.09855v1 + physics.optics + physics.app-ph + Thu, 11 Dec 2025 00:00:00 -0500 + new http://creativecommons.org/licenses/by/4.0/ - Viktoriia Borovik, Hannah Friedman, Serkan Ho\c{s}ten, Max Pfeffer + Andrew J. Shepherd, Daniel J. Blumenthal, Ryan O. Behunin - Solar neutron and muon detection on November 11, 2025: First simultaneous recovery of energy spectra - https://arxiv.org/abs/2512.07859 - arXiv:2512.07859v1 Announce Type: cross -Abstract: Ground Level Enhancement (GLE) events provide rare opportunities to study high-energy solar particle acceleration through direct detection of secondary radiation at ground level. On November 11, 2025, the Aragats Solar Neutron Telescope (ASNT) recorded a statistically significant increase in high-energy neutron and muon fluxes associated with an X5.1 flare and the subsequent Solar Energetic Proton (SEP) event. The event displayed a unique dual-peak profile: an initial hard component at 10 28 UT, followed by a softer yet still energetic peak at 10 45 UT. For the first time, we report simultaneous energy spectra of atmospheric neutrons and muons measured in the 10 600 MeV range at Aragats. Broken-power-law fits reveal a clear temporal evolution of acceleration conditions, evidenced by spectral indices declining with energy. These findings highlight the unique capabilities of the ASNT as an instrument for studying extreme solar particle acceleration. - oai:arXiv.org:2512.07859v1 - astro-ph.SR - physics.ao-ph - physics.space-ph - Wed, 10 Dec 2025 00:00:00 -0500 - cross - http://creativecommons.org/licenses/by/4.0/ - A. Chilingarian, B. Sargsyan, L. Kozliner, T. Karapetyan + A GPU-Accelerated Fully Coupled Fluid-Solid-Thermal SPH Solver for Industrial Gearboxes: Application to Lubricant Flow and Heat Transfer in a Bevel-Helical Reducer + https://arxiv.org/abs/2512.09904 + arXiv:2512.09904v1 Announce Type: new +Abstract: This study presents a GPU-accelerated, fully coupled fluid-solid-thermal Smoothed Particle Hydrodynamics (SPH) framework for high-fidelity analysis of splash-lubricated gearboxes. A series of thermo-fluid simulations of a bevel-helical gear reducer were conducted by varying shaft speed, oil immersion depth, and lubricant viscosity to evaluate their influence on splash dynamics, churning losses, and lubricant temperature rise. The results show that churning losses increase by nearly an order of magnitude as the speed rises from 150 to 600 rad/s, while the corresponding lubricant temperature rise becomes approximately three to four times smaller. Variations in immersion depth and viscosity adjust the heating rate only modestly-typically within 10-20%-with their influence reversing between low- and high-speed regimes. The GPU backend provides a 7-9 speedup over a high-performance desktop CPU, enabling multi-million-particle, full-gearbox thermo-fluid simulations without specialized hardware. These findings demonstrate the feasibility of high-fidelity thermal analysis of industrial gearboxes and provide quantitative insight into the coupled splash, churning, and heat-transfer mechanisms that govern gearbox thermal performance. + oai:arXiv.org:2512.09904v1 + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Yongchuan Yu, Dong Wu, Oskar J. Haidn, Xiangyu Hu - Softly Symbolifying Kolmogorov-Arnold Networks - https://arxiv.org/abs/2512.07875 - arXiv:2512.07875v1 Announce Type: cross -Abstract: Kolmogorov-Arnold Networks (KANs) offer a promising path toward interpretable machine learning: their learnable activations can be studied individually, while collectively fitting complex data accurately. In practice, however, trained activations often lack symbolic fidelity, learning pathological decompositions with no meaningful correspondence to interpretable forms. We propose Softly Symbolified Kolmogorov-Arnold Networks (S2KAN), which integrate symbolic primitives directly into training. Each activation draws from a dictionary of symbolic and dense terms, with learnable gates that sparsify the representation. Crucially, this sparsification is differentiable, enabling end-to-end optimization, and is guided by a principled Minimum Description Length objective. When symbolic terms suffice, S2KAN discovers interpretable forms; when they do not, it gracefully degrades to dense splines. We demonstrate competitive or superior accuracy with substantially smaller models across symbolic benchmarks, dynamical systems forecasting, and real-world prediction tasks, and observe evidence of emergent self-sparsification even without regularization pressure. - oai:arXiv.org:2512.07875v1 - cs.LG - cs.NE - physics.data-an - stat.ML - Wed, 10 Dec 2025 00:00:00 -0500 - cross + A Model Intercomparison Study of Mixed-Phase Clouds in a Laboratory Chamber + https://arxiv.org/abs/2512.09915 + arXiv:2512.09915v1 Announce Type: new +Abstract: Mixed-phase clouds, composed of supercooled liquid droplets and ice crystals, play a critical role in weather and climate systems. Their complex microphysical interactions and coupling with turbulence at microscales govern the cloud properties at macroscales, yet remain challenging to observe and quantify under atmospheric conditions. This model intercomparison study utilizes ten model configurations to simulate mixed-phase cloud evolution in the Michigan Technological University's Pi Chamber. The models span a range of frameworks, including box models, direct numerical simulation, and large-eddy simulation models, and incorporate both bin and Lagrangian microphysics. Each model was tuned to reproduce the observed liquid-phase steady state prior to ice injection. Ice particles were then introduced into the domain at various rates to examine cloud glaciation behavior. By the intercomparison design, all models successfully reproduced the observed mean droplet radius and number concentration during the liquid-phase stage. Increasing ice particle injection rates led to consistent qualitative trends across models: depletion of liquid water, reduced total water content, and a shift in particle size distributions toward larger radii. However, quantitative differences arose due to variations in model treatment in dynamics and microphysics, including subgrid-scale turbulence parameterizations, wall forcing, and particle removal parameterizations. Most models that simulate the full chamber retained liquid droplets near the lower boundary, where supersaturation forcing is strongest and droplets are replenished before mixing into the core region. These surviving liquids droplets were absent in simulations assuming a well-mixed domain, excluding the near-wall region, or using coarse grid spacing. + oai:arXiv.org:2512.09915v1 + physics.ao-ph + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 + new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - James Bagrow, Josh Bongard + Aaron Wang, Sisi Chen, Steve Krueger, Piotr Dziekan, Kotaro Enokido, Fabian Hoffmann, Agnieszka Makulska, Bernhard Mehlig, Gaetano Sardina, Grigory Sarnitsky, Silvio Schmalfu{\ss}, Shin-ichiro Shima, Fan Yang, Mikhail Ovchinnikov, Raymond A. Shaw - Revised comment on the paper titled "The Origin of Quantum Mechanical Statistics: Insights from Research on Human Language - https://arxiv.org/abs/2512.07881 - arXiv:2512.07881v1 Announce Type: cross -Abstract: This short note comments on \citet{Aerts2024Origin}, which proposes that ranked word frequencies in texts should be read through the lens of Bose--Einstein (BE) statistics and even used to illuminate the origin of quantum statistics in physics. The core message here is modest: the paper offers an interesting analogy and an eye-catching fit, but several key steps mix physical claims with definitions and curve-fitting choices. We highlight three such points: (i) a normalization issue that is presented as "bosonic enhancement", (ii) an identification of rank with energy that makes the BE fit only weakly diagnostic of an underlying mechanism, and (iii) a baseline comparison that is too weak to support an ontological conclusion. We also briefly flag a few additional concerns (interpretation drift, parameter semantics, and reproducibility). - oai:arXiv.org:2512.07881v1 - q-bio.NC - physics.hist-ph - Wed, 10 Dec 2025 00:00:00 -0500 - cross - http://creativecommons.org/licenses/by/4.0/ - Miko{\l}aj Sienicki, Krzysztof Sienicki + Buoyancy-dependent induced flow by vertically migrating swimmers + https://arxiv.org/abs/2512.09916 + arXiv:2512.09916v1 Announce Type: new +Abstract: Collective vertical migrations of negatively buoyant swimmers can drive large-scale fluid transport. In the ocean, zooplankton migrate over vertical distances several orders of magnitude larger than their body length. These swimmers experience changes in their buoyancy relative to the stably stratified ocean water column. The impact of net swimmer buoyancy on the scale of aggregate-scale induced flows remains unresolved. We hypothesize that as the net buoyancy of swimmers becomes increasingly negative the speed of induced flow in the opposite direction of swimming will increase due to changes in the required force to swim upward and thus the momentum imparted on the surrounding fluid. Simultaneous three-dimensional swimmer tracking and two-dimensional two-component flow measurements are used to measure the flow induced by collective vertical migration of Artemia salina. Experiments were designed to modulate the buoyant force on the swimmers by changing environmental salinity. Experimental results supported the hypothesis and were used to develop a theoretical model, which was then used to contextualize results to ocean relevant conditions with non-dimensional analysis. + oai:arXiv.org:2512.09916v1 + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Nina Mohebbi, John O. Dabiri - SATMO: a Multi-Planet Thermal Analysis Tool for CubeSat Missions - https://arxiv.org/abs/2512.07896 - arXiv:2512.07896v1 Announce Type: cross -Abstract: The expansion of commercial launch capabilities has significantly increased opportunities for interplanetary small satellite (SmallSat) missions. As researchers plan for more missions beyond Earth, there is a demand for accessible tools that help better predict and understand the thermal effects on their spacecraft in orbital environments around Earth and other bodies. While commercial thermal analysis tools offer high-fidelity modeling capabilities and results, they are often expensive and require extensive training to be used effectively. This paper details a framework for a user-friendly Satellite Thermal Model (SATMO) to support the early stages of space mission planning for CubeSats orbiting Earth and other Solar System bodies. SATMO is an open-source, MATLAB-based, six-node thermal analysis program designed for satellites in low-altitude circular orbits. Although SATMO requires a MATLAB license -- typically inexpensive or institutionally provided in academic settings -- it remains substantially more accessible than professional thermal analysis software. SATMO requires an internet connection for some features but does not rely on additional MATLAB toolboxes. The SATMO modeling approach is validated with the space industry standard Thermal Desktop software, with temperatures comparable to within 1.17$^\circ$C for a 10 cm $\times$ 10 cm $\times$ 10 cm CubeSat in various configurations, orbiting around primary bodies including Earth, Venus, and Mars. An example use case of SATMO is presented with a Mars-orbiting CubeSat to demonstrate its functionalities and the outputs available to users. SATMO offers increased accessibility to satellite thermal modeling for the research community, enabling quick thermal trade studies and interplanetary mission plans. - oai:arXiv.org:2512.07896v1 - astro-ph.IM - physics.app-ph - Wed, 10 Dec 2025 00:00:00 -0500 - cross + Evaluating Function-as-a-Service (FaaS) frameworks for the Accelerator Control System + https://arxiv.org/abs/2512.09917 + arXiv:2512.09917v1 Announce Type: new +Abstract: As particle accelerator control systems evolve in complexity and scale, the need for responsive, scalable, and cost-effective computational infrastructure becomes increasingly critical. Function-as-a-Service (FaaS) offers an alternative to traditional monolithic architecture by enabling event-driven execution, automatic scaling, and fine-grained resource utilization. This paper explores the applicability and performance of FaaS frameworks in the context of a modern particle accelerator control system, with the objective of evaluating their suitability for short lived and triggered workloads. In this paper, we evaluate prominent open-source FaaS platforms in executing functional logic, triggers, and diagnostics routines. Evaluation metrics consist of cold-start latency, scalability, performance, integration with other open-source tools like Kafka. Experimental workloads were designed to simulate real-world control tasks when implemented as stateless FaaS functions. These workloads were benchmarked under various invocation loads and network conditions. Self-hosted FaaS platforms, when deployed within accelerator networks, offer greater control over execution environment, better integration with legacy systems, and support for real-time guarantees when paired with message queues. Based on lessons learned and evaluation metrics, this paper describes reliability of the FaaS framework for the Accelerator Control Systems (ACS). + oai:arXiv.org:2512.09917v1 + physics.acc-ph + Thu, 11 Dec 2025 00:00:00 -0500 + new http://creativecommons.org/licenses/by/4.0/ - Alexander Chipps, Daniel Forgette, Kerri Cahoy - - - CFD-copilot: leveraging domain-adapted large language model and model context protocol to enhance simulation automation - https://arxiv.org/abs/2512.07917 - arXiv:2512.07917v1 Announce Type: cross -Abstract: Configuring computational fluid dynamics (CFD) simulations requires significant expertise in physics modeling and numerical methods, posing a barrier to non-specialists. Although automating scientific tasks with large language models (LLMs) has attracted attention, applying them to the complete, end-to-end CFD workflow remains a challenge due to its stringent domain-specific requirements. We introduce CFD-copilot, a domain-specialized LLM framework designed to facilitate natural language-driven CFD simulation from setup to post-processing. The framework employs a fine-tuned LLM to directly translate user descriptions into executable CFD setups. A multi-agent system integrates the LLM with simulation execution, automatic error correction, and result analysis. For post-processing, the framework utilizes the model context protocol (MCP), an open standard that decouples LLM reasoning from external tool execution. This modular design allows the LLM to interact with numerous specialized post-processing functions through a unified and scalable interface, improving the automation of data extraction and analysis. The framework was evaluated on benchmarks including the NACA~0012 airfoil and the three-element 30P-30N airfoil. The results indicate that domain-specific adaptation and the incorporation of the MCP jointly enhance the reliability and efficiency of LLM-driven engineering workflows. - oai:arXiv.org:2512.07917v1 - cs.SE - cs.AI - physics.flu-dyn - Wed, 10 Dec 2025 00:00:00 -0500 - cross - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Zhehao Dong, Shanghai Du, Zhen Lu, Yue Yang + 10.18429/JACoW-ICALEPCS2025-THBR003 + JACoW 2025 + A. Jaikar (Fermi National Accelerator Laboratory), J. Diamond (Fermi National Accelerator Laboratory), A. Tiradani (Fermi National Accelerator Laboratory), B. Harrison (Fermi National Accelerator Laboratory) - Microlensing Signatures of Dyson Sphere-like Structures around Primordial Black Holes as Technosignatures of Extraterrestrial Advanced Civilizations - https://arxiv.org/abs/2512.07924 - arXiv:2512.07924v1 Announce Type: cross -Abstract: We investigate the microlensing detectability of extraterrestrial technosignatures originating from Dyson sphere \textendash like structures, such as Dyson Swarms surrounding primordial black holes (PBHs). These hypothetical swarms consist of stochastically varying, partially opaque structures that could modulate standard microlensing light curves through time-dependent transmission effects. We introduce a probabilistic framework that includes a stochastic transmission model governed by variable optical depth and random gap distributions. We perform a parameter scan and generate heatmaps of the optical transit duration. We study the infrared excess radiation and peak emission wavelength as complementary observational signatures. Additionally, we define and analyze the effective optical depth and the anomalous microlensing event rate for these stochastic structures. Our findings provide a new avenue for searching for extraterrestrial advanced civilizations by extending microlensing studies to include artificial, dynamic modulation signatures. - oai:arXiv.org:2512.07924v1 - astro-ph.IM - astro-ph.CO - astro-ph.EP - physics.pop-ph - Wed, 10 Dec 2025 00:00:00 -0500 - cross + Optical arbitrary waveform generation using spectro-temporal unitary transforms + https://arxiv.org/abs/2512.09919 + arXiv:2512.09919v1 Announce Type: new +Abstract: We discuss the prospect of using cascaded phase modulators and dispersive elements to achieve arbitrary optical waveform generation. This transform is not limited by the bandwidth of its constituent modulators and is theoretically lossless. + oai:arXiv.org:2512.09919v1 + physics.optics + eess.SP + Thu, 11 Dec 2025 00:00:00 -0500 + new http://creativecommons.org/licenses/by/4.0/ - Shant Baghram + Callum Deakin - Vortex leapfrogging and superfluid dissipation mechanisms in a fluid of light - https://arxiv.org/abs/2512.07935 - arXiv:2512.07935v1 Announce Type: cross -Abstract: We report the experimental observation of vortex leapfrogging in a two-dimensional fluid of light. By imprinting two vortex-antivortex pairs and tracking their real-time evolution through phase-resolved imaging, we observe a dynamics that is accurately described by a point-vortex model with an outward background flow. By precisely controlling the initial vortex separation, we identify configurations in which leapfrogging breaks down and determine the corresponding dissipation mechanisms. The first originates from phase-slip events occurring at large injected velocities. The second arises when the injection of multi-charged vortices leads to the formation of a dispersive shock wave which acts as a continuous source of phase slippage. These mechanisms advance our understanding of vortex dynamics and dissipation in superfluids. - oai:arXiv.org:2512.07935v1 - cond-mat.quant-gas + Graph Deep Learning for Intracranial Aneurysm Blood Flow Simulation and Risk Assessment + https://arxiv.org/abs/2512.09013 + arXiv:2512.09013v1 Announce Type: cross +Abstract: Intracranial aneurysms remain a major cause of neurological morbidity and mortality worldwide, where rupture risk is tightly coupled to local hemodynamics particularly wall shear stress and oscillatory shear index. Conventional computational fluid dynamics simulations provide accurate insights but are prohibitively slow and require specialized expertise. Clinical imaging alternatives such as 4D Flow MRI offer direct in-vivo measurements, yet their spatial resolution remains insufficient to capture the fine-scale shear patterns that drive endothelial remodeling and rupture risk while being extremely impractical and expensive. + We present a graph neural network surrogate model that bridges this gap by reproducing full-field hemodynamics directly from vascular geometries in less than one minute per cardiac cycle. Trained on a comprehensive dataset of high-fidelity simulations of patient-specific aneurysms, our architecture combines graph transformers with autoregressive predictions to accurately simulate blood flow, wall shear stress, and oscillatory shear index. The model generalizes across unseen patient geometries and inflow conditions without mesh-specific calibration. Beyond accelerating simulation, our framework establishes the foundation for clinically interpretable hemodynamic prediction. By enabling near real-time inference integrated with existing imaging pipelines, it allows direct comparison with hospital phase-diagram assessments and extends them with physically grounded, high-resolution flow fields. + This work transforms high-fidelity simulations from an expert-only research tool into a deployable, data-driven decision support system. Our full pipeline delivers high-resolution hemodynamic predictions within minutes of patient imaging, without requiring computational specialists, marking a step-change toward real-time, bedside aneurysm analysis. + oai:arXiv.org:2512.09013v1 + cs.LG physics.flu-dyn - quant-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - Myrann Baker-Rasooli, Nathan du Toit, Nicolas Pavloff, Quentin Glorieux - - - Neutrino Effects on Atomic Measurements of the Weinberg Angle - https://arxiv.org/abs/2512.07938 - arXiv:2512.07938v1 Announce Type: cross -Abstract: We derive a complete expression for the neutrino-mediated quantum force beyond the four-Fermi approximation within the Standard Model. Using this new result, we study the effect of atomic parity violation caused by neutrinos. We find that the neutrino effect is sizable compared to the current experimental sensitivity and can also significantly affect the value of the Weinberg angle measured in atomic systems. This offers a promising method for detecting the neutrino force in the future and facilitates the application of precision atomic physics as a probe for neutrino physics and the electroweak sector of the Standard Model. - oai:arXiv.org:2512.07938v1 - hep-ph - hep-ex - physics.atom-ph - Wed, 10 Dec 2025 00:00:00 -0500 - cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Mitrajyoti Ghosh, Yuval Grossman, Chinhsan Sieng, Bingrong Yu + Paul Garnier, Pablo Jeken-Rico, Vincent Lannelongue, Chiara Faitini, Aur\`ele Goetz, Lea Chanvillard, Ramy Nemer, Jonathan Viquerat, Ugo Pelissier, Philippe Meliga, Jacques S\'edat, Thomas Liebig, Yves Chau, Elie Hachem - Classical and quantum dynamics of a particle confined in a paraboloidal cavity - https://arxiv.org/abs/2512.08021 - arXiv:2512.08021v1 Announce Type: cross -Abstract: We present a classical and quantum analysis of a particle confined in a three-dimensional paraboloidal cavity formed by two confocal paraboloids. Classically, the system is integrable and presents three independent constants of motion, namely, the energy, the $z$-component of the angular momentum, and a third dynamical constant associated with the paraboloidal geometry, which can be derived from the separability of the Hamilton--Jacobi equation. We derive closed-form analytical expressions for the actions, which allow us to determine the two conditions to get periodic closed trajectories. We classify these trajectories through the indices $(s,t,\ell)$. The caustic paraboloids that bound the motion provide a complete geometric characterization of admissible trajectories. Quantum mechanically, separability of the Schr\"odinger equation in parabolic coordinates yields eigenmodes described by Whittaker functions. We determine the energy spectrum and identify degeneracies arising not only from azimuthal symmetry but also from specific cavity deformations. A direct correspondence between classical trajectories and quantum eigenstates reveals that probability densities concentrate in the classically allowed region with controlled penetration into forbidden zones. - oai:arXiv.org:2512.08021v1 - quant-ph - math-ph - math.MP - physics.class-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Non-Equilibrium Thermodynamics of Black-Hole Coronae: QPOs, Turbulence, and Jets + https://arxiv.org/abs/2512.09026 + arXiv:2512.09026v1 Announce Type: cross +Abstract: The variability of X-rays observed from accreting black hole systems, including quasi-periodic oscillations (QPOs), suggests a complex nonlinear dynamics in the corona. Here, we propose a new theoretical framework for this problem, based on non-equilibrium thermodynamics. In this model, coronal variability arises from feedback between a macroscopic oscillation of the plasma and the rate at which it is cooled by the inverse Compton scattering of soft photons from the disc. The "pair thermostat'' mechanism then allows the corona to act as a heat engine that extracts work cyclically from the underlying thermal disequilibrium between the low-entropy heating and the high-entropy cooling by the soft photons, in close analogy to the well-known $\kappa$-mechanism for pulsating stars. This coronal self-oscillation may explain QPOs without the need to invoke an external resonant driving. Moreover, we argue that this mechanism can provide the power to generate turbulence and jets in the corona. + oai:arXiv.org:2512.09026v1 + astro-ph.HE + physics.flu-dyn + physics.plasm-ph + Thu, 11 Dec 2025 00:00:00 -0500 cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - \'Angel E. Reyna-Cruz, Julio C. Guti\'errez-Vega + Vanessa L\'opez-Barquero (University of Maryland, College Park), Alejandro Jenkins (Universidad de Costa Rica, University of Gda\'nsk), Christopher S. Reynolds (University of Maryland, College Park), Andrew Fabian (University of Cambridge) - Observation of a Topological Berry Phase with a Single Phonon in an Ion Microtrap Array - https://arxiv.org/abs/2512.08037 - arXiv:2512.08037v1 Announce Type: cross -Abstract: Controlled quantum mechanical motion of trapped atomic ions can be used to simulate and explore collective quantum phenomena and to process quantum information. Groups of cold atomic ions in an externally applied trapping potential self-organize into "Coulomb crystals" due to their mutual electrostatic repulsion. The motion of the ions in these crystals is strongly coupled, and the eigenmodes of motion all involve multiple ions. While this enables studies of many-body physics, it limits the flexibility and tunability of the system as a quantum platform. Here, we demonstrate an array of trapped ions in individual trapping sites whose motional modes can be controllably coupled and decoupled by tuning the local applied confining potential for each ion. We show that a single motional quantum, or phonon, can be coherently shared among two or three ions confined at the vertices of an equilateral triangle 30 $\mu$m on a side. We can adiabatically tune the ion participation in the motional modes around a closed contour in configuration space, observing that the single-phonon wavefunction acquires a topological Berry phase if the contour encircles a conical intersection of motional eigenvalue surfaces. We observe this phase by single-phonon interference and study its breakdown as the motional mode tuning becomes non-adiabiatic. Our results show that precise, individual quantum control of ion motion in a two-dimensional array can provide unique access to quantum multi-body effects. - oai:arXiv.org:2512.08037v1 + Subradiant collective states for precision sensing via transmission spectra + https://arxiv.org/abs/2512.09050 + arXiv:2512.09050v1 Announce Type: cross +Abstract: When an ensemble of quantum emitters interacts with a common radiation field, their emission becomes collective, giving rise to superradiant and subradiant states, characterized by broadened and narrowed linewidths. In this work, we propose to harness subradiant states for quantum metrology; such states naturally arise in subwavelength-spaced atomic arrays in free space and in small ensembles of emitters coupled to one-dimensional waveguides. We demonstrate that their collective optical response yields sharp, narrow features in the transmittance spectrum, which can be used to enhance sensitivity to external perturbations. This improved sensitivity can be applied to atomic clock operation, spatially resolved imaging of emitter positions, and enables precise detection of both global and spatially varying detunings (such as those induced by electromagnetic fields or gravitational gradients). + oai:arXiv.org:2512.09050v1 quant-ph physics.atom-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 cross - http://creativecommons.org/licenses/by/4.0/ - Justin F. Niedermeyer, Nathan K. Lysne, Katherine C. McCormick, Jonas Keller, Craig W. Hogle, Matthew G. Blain, Roman Schmied, Robert J\"ordens, Susanna L. Todaro, David J. Wineland, Andrew C. Wilson, Daniel H. Slichter, Dietrich Leibfried + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Diego Zafra-Bono, Oriol Rubies-Bigorda, Susanne F. Yelin - Emergent memory in cell-like active systems - https://arxiv.org/abs/2512.08058 - arXiv:2512.08058v1 Announce Type: cross -Abstract: Active systems across scales, ranging from molecular machines to human crowds, are usually modeled as assemblies of self-propelled particles driven by internally generated forces. However, these models often assume memoryless dynamics and no coupling of internal active forces to the environment. Here, guided by the example of living cells, which have recently been shown to display multi-timescale memory effects, we introduce a general theoretical framework that goes beyond this paradigm by incorporating internal state dynamics and environmental sensing into active particle models. We show that when the self-propulsion of an agent depends on internal variables with their own complex dynamics - modulated by local environmental cues - environmental memory spontaneously emerges and gives rise to new classes of behaviours. These include memory-induced responses, adaptable localization in complex landscapes, suppression of motility-induced phase separation, and enhanced jamming transitions. Our results demonstrate how minimal information processing capabilities, intrinsic to non-equilibrium agents with internal states like living cells, can profoundly influence both individual and collective behaviours. This framework bridges cell-scale activity and large-scale intelligent motion in cell assemblies, and opens the way to the quantitative analysis and design of systems ranging from synthetic colloids to biological collectives and robotic swarms. - oai:arXiv.org:2512.08058v1 - cond-mat.stat-mech - physics.bio-ph - Wed, 10 Dec 2025 00:00:00 -0500 + High Order Numerical Methods Preserving Invariant Domain for Hyperbolic and Related Systems + https://arxiv.org/abs/2512.09116 + arXiv:2512.09116v1 Announce Type: cross +Abstract: Admissible states in hyperbolic systems and related equations often form a convex invariant domain. Numerical violations of this domain can lead to loss of hyperbolicity, resulting in illposedness and severe numerical instabilities. It is therefore crucial for numerical schemes to preserve the invariant domain to ensure both physically meaningful solutions and robust computations. For complex systems, constructing invariant-domain-preserving (IDP) schemes is highly nontrivial and particularly challenging for high-order accurate methods. This paper presents a comprehensive survey of IDP schemes for hyperbolic and related systems, with a focus on the most popular approaches for constructing provable IDP schemes. We first give a systematic review of the fundamental approaches for establishing the IDP property in first-order accurate schemes, covering finite difference, finite volume, finite element, and residual distribution methods. Then we focus on two widely used and actively developed classes of high order IDP schemes as well as their recent developments, most of which have emerged in the past decade. The first class of methods seeks an intrinsic weak IDP property in high-order schemes and then designs polynomial limiters to enforce a strong IDP property at the points of interest. This generic approach applies to high-order finite volume and discontinuousGalerkin schemes. The second class is based on the flux limiting approaches, which originated from the flux-corrected transport method and can be adapted to a broader range of spatial discretizations, including finite difference and continuous finite element methods. In this survey, we elucidate the main ideas in the construction of IDP schemes, provide some new perspectives and insights, with extensive examples, and numerical experiments in gas dynamics and magnetohydrodynamics. + oai:arXiv.org:2512.09116v1 + math.NA + astro-ph.IM + cs.NA + physics.comp-ph + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Marc Besse, Rapha\"el Voituriez + Kailiang Wu, Xiangxiong Zhang, Chi-Wang Shu - Understanding the temperature response of biological systems: From empirical fits to mechanistic frameworks - https://arxiv.org/abs/2512.08074 - arXiv:2512.08074v1 Announce Type: cross -Abstract: Virtually every biological rate changes with temperature, but the mechanisms underlying these responses differ between different processes. Here, we bring together the main theoretical approaches used to describe temperature-rate relationships, ranging from empirical curve shapes to reaction-level kinetics and network-based dynamical frameworks. These models highlight how temperature influences not only the speed of elementary reactions, but also the behavior that emerges when many reactions interact through regulation, feedback, or stochastic transitions. By outlining the assumptions and implications of each perspective, we aim to clarify how different modeling strategies connect molecular processes to physiological temperature response curves and to point toward integrative frameworks that can better explain the diversity of biological thermal responses. - oai:arXiv.org:2512.08074v1 - q-bio.QM - cond-mat.soft - cond-mat.stat-mech - nlin.AO - physics.bio-ph - Wed, 10 Dec 2025 00:00:00 -0500 + A Hybrid Neural Network-Finite Element Method for the Viscous-Plastic Sea-Ice Model + https://arxiv.org/abs/2512.09118 + arXiv:2512.09118v1 Announce Type: cross +Abstract: We present an efficient hybrid Neural Network-Finite Element Method (NN-FEM) for solving the viscous-plastic (VP) sea-ice model. The VP model is widely used in climate simulations to represent large-scale sea-ice dynamics. However, the strong nonlinearity introduced by the material law makes VP solvers computationally expensive, with the cost per degree of freedom increasing rapidly under mesh refinement. High spatial resolution is particularly required to capture narrow deformation bands known as linear kinematic features in viscous-plastic models. To improve computational efficiency in simulating such fine-scale deformation features, we propose to enrich coarse-mesh finite element approximations with fine-scale corrections predicted by neural networks trained with high-resolution simulations. The neural network operates locally on small patches of grid elements, which is efficient due to its relatively small size and parallel applicability across grid patches. An advantage of this local approach is that it generalizes well to different right-hand sides and computational domains, since the network operates on small subregions rather than learning details tied to a specific choice of boundary conditions, forcing, or geometry. The numerical examples quantify the runtime and evaluate the error for this hybrid approach with respect to the simulation of sea-ice deformations. Applying the learned network correction enables coarser-grid simulations to achieve qualitatively similar accuracy at approximately 11 times lower computational cost relative to the high-resolution reference simulations. Moreover, the learned correction accelerates the Newton solver by up to 10% compared to runs without the correction at the same mesh resolution. + oai:arXiv.org:2512.09118v1 + math.NA + cs.NA + physics.comp-ph + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 cross - http://creativecommons.org/licenses/by/4.0/ - Simen Jacobs, Julian Voits, Nikita Frolov, Ulrich S. Schwarz, Lendert Gelens + http://creativecommons.org/licenses/by-sa/4.0/ + Nils Margenberg, Carolin Mehlmann - Predicting interstitial elements in Refractory Complex Concentrated Alloys - https://arxiv.org/abs/2512.08080 - arXiv:2512.08080v1 Announce Type: cross -Abstract: Refractory complex concentrated alloys, composed of multiple principal refractory elements, are promising candidates for high-temperature structural applications due to their exceptional thermal stability and high melting points. However, their mechanical performance is often compromised by interstitial impurities, particularly oxygen, nitrogen, and carbon, which segregate to grain boundaries and promote embrittlement. In this study, we investigate the solubility and thermodynamic behavior of oxygen interstitials in a model NbTiHfTa RCCA system. We synthesized NbTiHfTa alloys with varying oxygen contents via plasma arc melting and characterized their phase evolution and microstructure using XRD, SEM, and TEM. Complementary computational modeling was performed using machine-learning interatomic potentials integrated with Monte Carlo simulations to probe oxygen interactions at the atomic scale. Our results reveal a solubility limit for oxygen between 0.8 and 1.0 atomic percentage, beyond which HfO2 formation is energetically favorable. This combined experimental-computational framework provides a predictive approach for managing interstitial behavior in RCCAs, enabling improved alloy design strategies for enhanced mechanical performance. - oai:arXiv.org:2512.08080v1 + Skyrmion Sliding Switch in a 90-nm-Wide Nanostructured Chiral Magnet + https://arxiv.org/abs/2512.09225 + arXiv:2512.09225v1 Announce Type: cross +Abstract: Magnetic skyrmions, renowned for their fascinating electromagnetic properties, hold potential for next-generation topological spintronic devices. Recent advancements have unveiled a rich tapestry of 3D topological magnetism. Nevertheless, the practical application of 3D topological magnetism in the development of topological spintronic devices remains a challenge. Here, we showcase the experimental utilization of 3D topological magnetism through the exploitation of skyrmion-edge attractive interactions in 90-nm-wide confined chiral FeGe and CoZnMn magnetic nanostructures. These attractive interactions result in two degenerate equilibrium positions, which can be naturally interpreted as binary bits for a skyrmion sliding switch. Our theory and simulation reveal current-driven spiral motions of skyrmions, governed by the anisotropic gradient of the potential landscape. Our experiments validate the theory that predicts a tunable threshold current density via magnetic field and temperature modulation of the energy barrier. Our results offer an approach for implementing universal on-off switch functions in 3D topological spintronic devices. + oai:arXiv.org:2512.09225v1 + cond-mat.mes-hall cond-mat.mtrl-sci - physics.atom-ph - Wed, 10 Dec 2025 00:00:00 -0500 + physics.app-ph + Thu, 11 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - Aomin Huang, Siya Zhu, Calvin Belcher, Ryker Rigsby, Diran Apelian, Raymundo Arr\'oyave, Enrique J. Lavernia + 10.1021/acs.nanolett.5c00781 + Yaodong Wu, Jialiang Jiang, Weiwei Wang, Lingyao Kong, Shouguo Wang, Mingliang Tian, Haifeng Du, Jin Tang - Moire-Engineered Ferroelectric Transistors for Nearly Trap-free, Low-Power and Non-Volatile 2D Electronics - https://arxiv.org/abs/2512.08086 - arXiv:2512.08086v1 Announce Type: cross -Abstract: Long-range moire patterns in twisted WSe2 enable a built-in, moire-length-scale ferroelectric polarization that can be directly harnessed in electronic devices. Such a built-in ferroic landscape offers a compelling means to enable ultralow-voltage and non-volatile electronic functionality in two-dimensional materials; however, achieving stable polarization control without charge trapping has remained a persistent challenge. Here, we demonstrate a moire-engineered ferroelectric field-effect transistor (FeFET) utilizing twisted WSe2 bilayers that leverages atomically clean van der Waals interfaces to achieve efficient polarization-channel coupling and trap-suppressed, ultralow-voltage operation (subthreshold swing of 64 mV per decade). The device exhibits a stable non-volatile memory window of 0.10 V and high mobility, exceeding the performance of previously reported two-dimensional FeFET and matching that of advanced silicon-based devices. In addition, capacitance-voltage spectroscopy, corroborated by self-consistent Landau-Ginzburg-Devonshire modeling, indicates ultrafast ferroelectric switching (~0.5 microseconds). These results establish moire-engineered ferroelectricity as a practical and scalable route toward ultraclean, low-power, and non-volatile 2D electronics, bridging atomistic lattice engineering with functional device architectures for next-generation memory and logic technologies. - oai:arXiv.org:2512.08086v1 - cond-mat.mtrl-sci - cond-mat.mes-hall - cond-mat.str-el - physics.app-ph + Parallel accelerated electron paramagnetic resonance spectroscopy using diamond sensors + https://arxiv.org/abs/2512.09230 + arXiv:2512.09230v1 Announce Type: cross +Abstract: The nitrogen-vacancy (NV) center can serve as a magnetic sensor for electron paramagnetic resonance (EPR) measurements. Benefiting from its atomic size, the diamond chip can integrate a tremendous amount of NV centers to improve the magnetic-field sensitivity. However, EPR spectroscopy using NV ensembles is less efficient due to inhomogeneities in both sensors and targets. Spectral line broadening induced by ensemble averaging is even detrimental to spectroscopy. Here we show a kind of cross-relaxation EPR spectroscopy at zero field, where the sensor is tuned by an amplitude-modulated control field to match the target. The modulation makes detection robust to the sensor's inhomogeneity, while zero-field EPR is naturally robust to the target's inhomogeneity. We demonstrate an efficient EPR measurement on an ensemble of roughly 30000 NV centers. Our method shows the ability to not only acquire unambiguous EPR spectra of free radicals, but also monitor their spectroscopic dynamics in real time. + oai:arXiv.org:2512.09230v1 quant-ph - Wed, 10 Dec 2025 00:00:00 -0500 + physics.bio-ph + physics.chem-ph + Thu, 11 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + 10.1103/PhysRevLett.134.130801 + Phys. Rev. Lett. 134, 130801 (2025) + Zhehua Huang, Zhengze Zhao, Fei Kong, Zhecheng Wang, Pengju Zhao, Xiangtian Gong, Xiangyu Ye, Ya Wang, Fazhan Shi, Jiangfeng Du + + + Tracing a Multi-Temperature Quiescent Prominence's Thermodynamic Evolution from Sun to Earth + https://arxiv.org/abs/2512.09234 + arXiv:2512.09234v1 Announce Type: cross +Abstract: Solar prominences are cool, dense stable structures routinely observed in the corona. Prominences are often ejected from the Sun via coronal mass ejections (CMEs). However, they are rarely detected in a cool, low-ionized state within CMEs measured in situ, making their evolution hard to study. We examine the thermodynamic evolution of one of these rare cases where a quiescent prominence eruption clearly preserves its low-ionized charge state as evidenced by in situ detection. We use multi-viewpoint Extreme Ultraviolet (EUV) observations to track and estimate the density, temperature and speed of the prominence as it erupts. We observe that part of the prominence remains in absorption well beyond initial liftoff, indicating the bulk of the prominence experiences minimal ionization and suggesting any strong heating is balanced by radiative losses, expansion, or conduction. From its subsequent in situ passage near 1au, charge states reveal that the prominence is composed of both cool, low-ionized ions as well as hotter plasma reflected by the presence of highly ionized iron, Fe$^{16+}$. Simulated non-equilibrium ionization and recombination results using observationally derived initial conditions match the in situ multi-thermal state for a prominence composed of 70% cool plasma with a 1.8MK peak temperature, and 30% hot plasma with a 4.3MK peak temperature. This suggests that the prominence may not be heated uniformly or that parts of it cools more rapidly. The complex, multi-thermal nature of this erupting prominence emphasizes the need for more comprehensive spectral observations of the global corona. + oai:arXiv.org:2512.09234v1 + astro-ph.SR + physics.plasm-ph + Thu, 11 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - Arup Singha, Shaili Sett, Kenji Watanabe, Takashi Taniguchi, Arindam Ghosh, Rahul Debnath + Callie A. Garc\'ia, Yeimy J. Rivera, Samuel T. Badman, John C. Raymond, Katharine K. Reeves, Tatiana Niembro, Kristoff W. Paulson, Michael L. Stevens - Enhancing Hole Mobility in Monolayer $WSe_{2}$ p-FETs via Process-Induced Compression - https://arxiv.org/abs/2512.08148 - arXiv:2512.08148v1 Announce Type: cross -Abstract: Understanding the interactions between strain, interfacial mechanics, and electrical performance is critical for designing beyond silicon electronics based on hetero-integrated 2D materials. Through combined experiment and simulation, we demonstrated and analyzed the enhancement of hole mobility in p-type monolayer $WSe_{2}$ field effect transistors (FETs) under biaxial compression. We tracked FET performance versus strain by incrementing compressive strain to $WSe_{2}$ channels via sequential AlOx deposition and performing intermediate photoluminescence and transport measurements. The hole mobility factor increased at a rate of 340 $\pm$ 95 %/%$\epsilon$, and the on-current factor increased at a rate of 460 $\pm$ 340 %/%$\epsilon$. Simulation revealed that the enhancement under compression arises primarily from a reduction in inter-valley scattering between the $\Gamma$--K valence bands, and the rate is robust against variations in carrier density, impurity density, or dielectric environment. These findings show that compressive strain is a powerful technique for enhancing performance in 2D p-FETs and that it is multiplicative with defect and doping engineering. - oai:arXiv.org:2512.08148v1 + Predicting tunable nonreciprocal spin wave generation mediated by interfacial Dzyaloshinskii-Moriya interaction in magnonic heterostructures + https://arxiv.org/abs/2512.09240 + arXiv:2512.09240v1 Announce Type: cross +Abstract: Thin, metallic magnetic films can support nonreciprocal spin waves due to the interfacial Dzyaloshinskii-Moriya interaction (iDMI). However, these films typically have high damping, making spin wave propagation distances short (less than one micrometer). In this work, we theoretically study a thin ferromagnetic strip with iDMI and excite spin waves by driving a central segment of the strip. Spin waves propagate with different amplitudes to the left versus to the right from the driving region (i.e. nonreciprocity occurs) due to the iDMI. Our calculation based on spin-wave-dispersion plus our micromagnetic simulations both show that changing the driving segment width, driving frequency and static applied field strength tunes the nonreciprocity. Our calculation based on spin-wave-dispersion, using a so-called "overlap function" will allow researchers to predict conditions of maximum nonreciprocity, without the need for computational solvers. Moreover, to circumvent the issue of short propagation distances, we propose a geometry where iDMI is only present in the driving region and low-damping materials comprise the remainder of the strip. Our calculations show significant spin wave amplitudes over several microns from the excitation region. + oai:arXiv.org:2512.09240v1 cond-mat.mtrl-sci + cond-mat.other physics.app-ph - Wed, 10 Dec 2025 00:00:00 -0500 + physics.comp-ph + Thu, 11 Dec 2025 00:00:00 -0500 cross - http://creativecommons.org/licenses/by-nc-sa/4.0/ - He Lin Zhao, Sheikh Mohd Ta-Seen Afrid, Dongyoung Yoon, Zachary Martin, Zakaria Islam, Sihan Chen, Yue Zhang, Pinshane Y. Huang, Shaloo Rakheja, Arend M. van der Zande + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Cameron A McEleney, Karen L Livesey, Robert E Camley, Rair Mac\^edo - A Transcorrelated Wave-Function Framework for Solids: An Application to Bulk and Defected Silicon - https://arxiv.org/abs/2512.08276 - arXiv:2512.08276v1 Announce Type: cross -Abstract: Accurate wave-function descriptions of pristine and defected solids remain challenging due to the simultaneous presence of finite-size, basis-set, and correlation errors. While embedding techniques alleviate finite-size effects and correlated wave-function approaches systematically improve correlation, basis-set incompleteness continues to limit practical accuracy. Here we present a study of transcorrelated (TC) many-body wave-function methods on properties of solid state systems. We augment the existing xTC theory to periodic systems, and establish an unified transcorrelated embedding framework that integrates periodic TC theory with fragment-based correlated solvers. Using silicon as a test case, we validate the method against coupled-cluster, FCIQMC, and diffusion Monte Carlo benchmarks for bulk. Then we apply TC embedding to calculation of formation energies of two silicon self-interstitials. The TC Hamiltonian yields rapid basis convergence and quantitatively reliable defect formation energies at the triple-$\zeta$ level, substantially reducing the basis-set bottleneck for wave-function treatments of crystalline defects. - oai:arXiv.org:2512.08276v1 - cond-mat.mtrl-sci + GEARS - A Fully Run-Time Configurable Geant4 Application + https://arxiv.org/abs/2512.09246 + arXiv:2512.09246v1 Announce Type: cross +Abstract: The Geant4 toolkit is the standard for simulating the passage of particles through matter, but its conventional architecture often requires users to modify and recompile C++ code to alter fundamental simulation parameters such as geometry, physics list, and primary particle source. This architectural constraint introduces significant friction for new users and slows down the experimental iteration cycle. This paper introduces GEARS (Geant4 Example Application with Rich features yet Small footprint), a universally applicable Geant4 application that fundamentally addresses this issue. GEARS achieves complete simulation configurability without C++ recompilation by strictly utilizing external configuration methods: Geometry is defined via simple text-based configuration, the Physics List is selected via the standard PHYSLIST environment variable, and the Primary Source is defined through the General Particle Source (GPS) macro commands. Furthermore, regarding GEARS as an application instead of a framework, key features include a flat ntuple structure with short variable names for highly efficient analysis and a solution for capturing vital step zero data. Output creation is also fully managed via run-time macro commands and volume properties. The project is distributed as a ready-to-use Docker container to eliminate compilation barriers. Through these design considerations, GEARS transforms Geant4 into a practical, ready-to-use tool, enabling users to rapidly prototype and execute simulations for diverse experiments solely through simple text configuration files, without ever needing to modify or compile the underlying C++ source code. + oai:arXiv.org:2512.09246v1 + hep-ex physics.comp-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 cross - http://creativecommons.org/licenses/by/4.0/ - Kristoffer Simula, Johannes Hauskrecht, Evelin Martine Corvid Christlmaier, Pablo Lopez-Rios, Daniel Kats, Denis Usvyat, Ali Alavi + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Jing Liu - Forces at the scale of the cell - https://arxiv.org/abs/2512.08311 - arXiv:2512.08311v1 Announce Type: cross -Abstract: The importance of molecular-scale forces in sculpting biological form and function has been acknowledged for more than a century. Accounting for forces in biology is a problem that lies at the intersection of soft condensed matter physics, statistical mechanics, computer simulations and novel experimental methodologies, all adapted to a cellular context. This review surveys how forces arise within the cell. We provide a summary of the relevant background in basic biophysics, of soft-matter systems in and out of thermodynamic equilibrium, and of various force measurement methods in biology. We then show how these ideas can be incorporated into a description of cell-scale processes where forces are involved. Our examples include polymerization forces, motion of molecular motors, the properties of the actomyosin cortex, the mechanics of cell division, and shape changes in tissues. We show how new conceptual frameworks are required for understanding the consequences of cell-scale forces for biological function. We emphasize active matter descriptions, methodological tools that provide ways of incorporating non-equilibrium effects in a systematic manner into conceptual as well as quantitative descriptions. Understanding the functions of cells will necessarily require integrating the role of physical forces with the assimilation and processing of information. This integration is likely to have been a significant driver of evolutionary change. - oai:arXiv.org:2512.08311v1 - cond-mat.soft - cond-mat.stat-mech - physics.bio-ph - Wed, 10 Dec 2025 00:00:00 -0500 + The ONs and OFFs of Pulsar Radio Emission: Characterizing the Nulling Phenomenon + https://arxiv.org/abs/2512.09274 + arXiv:2512.09274v1 Announce Type: cross +Abstract: Radio emission from pulsars is known to exhibit a diverse range of emission phenomena, among which nulling, where the emission becomes temporarily undetectable, is an intriguing one. Observations suggest nulling is prevalent in many long-period pulsars and must be understood to obtain a more comprehensive picture of pulsar emission and its evolution. One of the limitations in observational characterisation of nulling is the limited signal-to-noise, making individual pulses often not easily distinguishable from noise or any putative faint emission. Although some of the approaches in the published literature attempt to address this, they lose efficacy when individual pulses appear indistinguishable from the noise, and as a result, can lead to less accurate measurements. Here we develop a new method (the $\mathbb{N}$sum algorithm) that uses sums of pulses for better distinguishability from noise and thus measures the nulling fraction more robustly. It can be employed for measuring nulling fractions in weaker pulsars and observations with a limited number of observed pulses. We compare our algorithm with the recently developed Gaussian Mixture Modelling approach, using both simulated and real data, and find that our approach yields consistent results for generic and weaker pulsars. We also explore quasi-periodicity in nulling and measure the related parameters for five pulsars, including PSRs~J1453$-$6413, J0950$+$0755 and J0026$-$1955, for which these are also the first such measurements. We compare and contrast our analysis of quasi-periodic nulling with previously published work and explore the use of spin-down energy loss ($\dot E$) to distinguish between different types of modulation behaviour. + oai:arXiv.org:2512.09274v1 + astro-ph.HE + physics.data-an + Thu, 11 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - K. Vijay Kumar, Mandar M. Inamdar, Pramod A. Pullarkat, Gautam I. Menon + Garvit Grover, N. D. Ramesh Bhat, Samuel J. McSweeney, Christopher P. Lee, Chia Min Tan, Shih Ching Fu, Bradley W. Meyers - Joint economic and epidemiological modelling of alternative pandemic response strategies - https://arxiv.org/abs/2512.08355 - arXiv:2512.08355v1 Announce Type: cross -Abstract: In an emerging pandemic, policymakers need to make important decisions with limited information, for example choosing between a mitigation, suppression or elimination strategy. These strategies may require trade-offs to be made between the health impact of the pandemic and the economic costs of the interventions introduced in response. Mathematical models are a useful tool that can help understand the consequences of alternative policy options on the future dynamics and impact of the epidemic. Most models have focused on direct health impacts, neglecting the economic costs of control measures. Here, we introduce a model framework that captures both health and economic costs. We use this framework to compare the expected aggregate costs of mitigation, suppression and elimination strategies, across a range of different epidemiological and economic parameters. We find that for diseases with low severity, mitigation tends to be the most cost-effective option. For more severe diseases, suppression tends to be most cost effective if the basic reproduction number $R_0$ is relatively low, while elimination tends to be more cost-effective if $R_0$ is high. We use the example of New Zealand's elimination response to the Covid-19 pandemic in 2020 to anchor our framework to a real-world case study. We find that parameter estimates for Covid-19 in New Zealand put it close to or above the threshold at which elimination becomes more cost-effective than mitigation. We conclude that our proposed framework holds promise as a decision-support tool for future pandemic threats, although further work is needed to account for population heterogeneity and other factors relevant to decision-making. - oai:arXiv.org:2512.08355v1 - q-bio.PE - physics.soc-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Single-crystalline high-quality beta-Ga2O3 pseudo-substrate on sapphire through sputtering for epitaxial deposition + https://arxiv.org/abs/2512.09294 + arXiv:2512.09294v1 Announce Type: cross +Abstract: Solid-phase epitaxy (SPE) of beta-Ga2O3 thin films by radio-frequency (RF) sputtering and then crystallized through high-temperature post-deposition annealing is employed on sapphire substrates, yielding a high-quality pseudo-substrate for subsequent buffer growth via MOCVD and LPCVD. Low roughness (<0.5 nm) and sharp single-crystalline diffraction peaks corresponding to the (-201), (-402), and (-603) reflections of beta-Ga2O3 were observed in the SPE beta-Ga2O3 film and the subsequent epitaxial buffer layer. N-doped Ga2O3 film on SPE Ga2O3 film grown by LPCVD showed step-assisted growth mode with reasonable electronic behavior with 45 cm^2/V-s mobility at a bulk carrier concentration of 1.3e17 cm^-3. These results suggest that SPE Ga2O3 is a promising pathway to advance the development of beta-Ga2O3 on foreign substrates. + oai:arXiv.org:2512.09294v1 + cond-mat.mtrl-sci + physics.app-ph + Thu, 11 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - M J Plank, M Sushames, T Fisher-Taylor, R N Thompson, A Hurford, S C Hendy + Guangying Wang (Department of Electrical and Computer Engineering, University of Wisconsin, Madison), Shuwen Xie (Department of Electrical and Computer Engineering, University of Wisconsin, Madison), William Brand (Agnitron Technology Inc), Saleh Ahmed Khan (Department of Electrical and Computer Engineering, University of Massachusetts Lowell), Ahmed Ibreljic (Department of Electrical and Computer Engineering, University of Massachusetts Lowell), Darryl Shima (Center for High Technology Materials, University of New Mexico), Yueying Ma (Department of Electrical and Computer Engineering, University of Wisconsin, Madison), Brahmani Challa (Department of Electrical and Computer Engineering, University of Wisconsin, Madison), Fikadu Alema (Agnitron Technology Inc), Andrei Osinsky (Agnitron Technology Inc), Anhar Bhuiyan (Department of Electrical and Computer Engineering, University of Massachusetts Lowell), Ganesh Balakrishnan (Center for High Technology Materials, University of New Mexico), Shubhra S. Pasayat (Department of Electrical and Computer Engineering, University of Wisconsin, Madison) - An extended low-frequency noise compact model for single-layer graphene FETs including correlated mobility fluctuations effect - https://arxiv.org/abs/2512.08388 - arXiv:2512.08388v1 Announce Type: cross -Abstract: Correlated mobility fluctuations are considered in the physics-based carrier number fluctuation deltaN low-frequency noise (LFN) compact model of single-layer graphene field effect transistors (GFET) in the present study. Trapped charge density and Coulomb scattering coefficient deltaN LFN parameters are obtained after applying a parameter extraction methodology, adapted from conventional silicon technologies, to the linear ambipolar regions of GFETs. Appropriate adjustments are considered in the method according to GFETs physical characteristics. Afterwards, Hooge mobility as well as series resistance fluctuations LFN parameters can be extracted. The updated LFN model is validated with experimental data from various long and short-channel GFETs at an extended range of gate and drain bias conditions. - oai:arXiv.org:2512.08388v1 - cond-mat.mes-hall - physics.app-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Routes of Transport in the Path Integral Lindblad Dynamics through State-to-State Analysis + https://arxiv.org/abs/2512.09362 + arXiv:2512.09362v1 Announce Type: cross +Abstract: Analyzing routes of transport for open quantum systems with non-equilibrium initial conditions is extremely challenging. The state-to-state approach [A. Bose, and P.L. Walters, J. Chem. Theory Comput. 2023, 19, 15, 4828-4836] has proven to be a useful method for understanding transport mechanisms in quantum systems interacting with dissipative thermal baths, and has been recently extended to non-Hermitian systems to account for empirical loss. These non-Hermitian descriptions are, however, not capable of describing empirical processes of more general nature, including but not limited to a variety of pumping processes. We extend the state-to-state analysis to account for Lindbladian descriptions of generic dissipative, pumping and decohering processes acting on a system which is exchanging energy with a thermal bath. This Lindblad state-to-state method can elucidate routes of transport in systems coupled to a bath and additionally acted upon by Lindblad jump operators. The method is demonstrated using examples of excitonic aggregates subject to incoherent pumping and draining processes. Using this new state-to-state formalism, we demonstrate the establishment of steady-state excitonic currents across molecular aggregates, yielding a different first-principles approach to quantifying the same. + oai:arXiv.org:2512.09362v1 + quant-ph + physics.chem-ph + Thu, 11 Dec 2025 00:00:00 -0500 cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1109/TED.2025.3640600 - IEEE Transactions on Electron Devices 2025 - Nikolaos Mavredakis, Anibal Pacheco-Sanchez, David Jimenez + Devansh Sharma, Amartya Bose - Practical protein-pocket hydration-site prediction for drug discovery on a quantum computer - https://arxiv.org/abs/2512.08390 - arXiv:2512.08390v1 Announce Type: cross -Abstract: Demonstrating the practical utility of Noisy Intermediate-Scale Quantum (NISQ) hardware for recurrent tasks in Computer-Aided Drug Discovery is of paramount importance. We tackle this challenge by performing three-dimensional protein pockets hydration-site prediction on a quantum computer. Formulating the water placement problem as a Quadratic Unconstrained Binary Optimization (QUBO), we use a hybrid approach coupling a classical three-dimensional reference-interaction site model (3D-RISM) to an efficient quantum optimization solver, to run various hardware experiments up to 123 qubits. Matching the precision of classical approaches, our results reproduced experimental predictions on real-life protein-ligand complexes. Furthermore, through a detailed resource estimation analysis, we show that accuracy can be systematically improved with increasing number of qubits, indicating that full quantum utility is in reach. Finally, we provide evidence that advantageous situations could be found for systems where classical optimization struggles to provide optimal solutions. The method has potential for assisting simulations of protein-ligand complexes for drug lead optimization and setup of docking calculations. - oai:arXiv.org:2512.08390v1 - quant-ph + Meta-learning three-factor plasticity rules for structured credit assignment with sparse feedback + https://arxiv.org/abs/2512.09366 + arXiv:2512.09366v1 Announce Type: cross +Abstract: Biological neural networks learn complex behaviors from sparse, delayed feedback using local synaptic plasticity, yet the mechanisms enabling structured credit assignment remain elusive. In contrast, artificial recurrent networks solving similar tasks typically rely on biologically implausible global learning rules or hand-crafted local updates. The space of local plasticity rules capable of supporting learning from delayed reinforcement remains largely unexplored. Here, we present a meta-learning framework that discovers local learning rules for structured credit assignment in recurrent networks trained with sparse feedback. Our approach interleaves local neo-Hebbian-like updates during task execution with an outer loop that optimizes plasticity parameters via \textbf{tangent-propagation through learning}. The resulting three-factor learning rules enable long-timescale credit assignment using only local information and delayed rewards, offering new insights into biologically grounded mechanisms for learning in recurrent circuits. + oai:arXiv.org:2512.09366v1 + q-bio.NC + cond-mat.dis-nn + cs.LG physics.bio-ph - physics.chem-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Dimitra Maoutsa + + + Electrical Characterization of High-k (k>115) Crystalline SrTiO3 (STO) thin film integration with GaN with Nanomembrane Transfer Process + https://arxiv.org/abs/2512.09391 + arXiv:2512.09391v1 Announce Type: cross +Abstract: High-k (115), crystalline SrTiO3 (STO) thin film was transferred on GaN for potential applications in power devices (transistor and diodes) by nanomembrane transfer method and the detailed electrical properties such as leakage current, CV profiles, dielectric constant, frequency dispersion was reported from fabricated MOSCAP structures. The leakage current was negligible (under noise-level of tool) up to 6 V and 11 V for 50 nm and 200 nm STO membrane respectively A high-quality dielectric was indicated by the CV profile, which showed almost negligible frequency dispersion in the frequency range of 10 kHz to 500 kHz. The dielectric constant was 50 to 82 with the 50 nm thick STO membrane and 115 to 186 in the 200 nm thick STO membrane. Thermal annealing of the membrane in ambient conditions at 250 degrees for 2 hours led to a slight improvement in the dielectric constant (8 to 20 percent), albeit at the expense of degraded leakage current performance, as indicated by a reduction of 1 V to 3 V in the "no leakage region" of the IV curves after annealing. The possible physical mechanisms responsible for these changes were also analyzed and discussed. + oai:arXiv.org:2512.09391v1 + cond-mat.mtrl-sci + physics.app-ph + Thu, 11 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - Daniele Loco, Kisa Barkemeyer, Andre R. R. Carvalho, Jean-Philip Piquemal + Md Tahmidul Alam, Kyoungjun Lee, Guangying Wang, Chang-beom Eom, Chirag Gupta - Many interacting particles in solution. I. Screening-ranged expansions of electrostatic potential and energy - https://arxiv.org/abs/2512.08407 - arXiv:2512.08407v1 Announce Type: cross -Abstract: We present an analytical many-body formalism for systems of spherical particles carrying arbitrary free charge distributions and interacting in a polarizable electrolyte solution, that we model within the linearized Poisson--Boltzmann framework. Building on the detailed spectral analysis of the associated nonstandard Neumann--Poincar\'e-type operators developed in our companion study~\cite{supplem_pre_math}, we construct exact explicit expansions of the electrostatic potential and energy in ascending orders of Debye screening thereby obtaining systematic "screening-ranged" series for potentials and energies. These screening-ranged expansions provide a unified and tractable description of many-body electrostatics. We demonstrate the versatility of the approach by showing how it generalizes and improves upon both classical and modern methods, enabling rigorous treatment of heterogeneously charged systems (such as Janus particles) and accurate modeling of higher-order phenomena (such as asymmetric dielectric screening, opposite-charge repulsion, like-charge attraction) as well as yielding many-body generalizations to analytical explicit results previously known only in the two-body setting. - oai:arXiv.org:2512.08407v1 + Exact Screening-Ranged Expansions for Many-Body Electrostatics + https://arxiv.org/abs/2512.09421 + arXiv:2512.09421v1 Announce Type: cross +Abstract: We present an exact many-body framework for electrostatic interactions among $N$ arbitrarily charged spheres in an electrolyte, modeled by the linearized Poisson--Boltzmann equation. Building on a spectral analysis of nonstandard Neumann--Poincar\'e-type operators introduced in a companion mathematical work~\cite{supplem_pre_math}, we construct convergent screening-ranged series for the potential, interaction energy, and forces, where each term is associated with a well-defined Debye--H\"uckel screening order and can be obtained evaluating an analytical expression rather than numerically solving an infinitely dimensional linear system. This formulation unifies and extends classical and recent approaches, providing a rigorous basis for electrostatic interactions among heterogeneously charged particles (including Janus colloids) and yielding many-body generalizations of analytical closed-form results previously available only for two-body systems. The framework captures and clarifies complex effects such as asymmetric dielectric screening, opposite-charge repulsion, and like-charge attraction, which remain largely analytically elusive in existing treatments. Beyond its fundamental significance, the method leads to numerically efficient schemes, offering a versatile tool for modeling colloids and soft/biological matter in electrolytic solution. + oai:arXiv.org:2512.09421v1 cond-mat.soft math-ph math.MP physics.bio-ph physics.chem-ph physics.comp-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ Sergii V. Siryk, Walter Rocchia - High-OAM Deep Ultraviolet Twisted Light Generation for RF-Photoinjector Applications - https://arxiv.org/abs/2512.08442 - arXiv:2512.08442v1 Announce Type: cross -Abstract: We report on the generation and characterization of ultraviolet (wavelength 266 nm) twisted light with high orbital angular momentum (OAM) using three types of fabricated diffractive optical elements (DOEs): a reflective fork grating, a high-charge spiral phase plate (SPP), and binary axicons. All elements were integrated into a drive-laser beamline of an electron RF-photoinjector, enabling direct evaluation under accelerator-relevant conditions. - The SPP produced a high-purity Laguerre-Gaussian mode with OAM l = 64 and a measured conversion efficiency of approximately 80\%. Binary axicons generated quasi-Bessel twisted light with topological charges up to m = 10, exhibiting low divergence and stable multi-lobe ring structures. The fork grating reliably produced lower-order modes, l = 2-8, with good agreement between simulations and cylindrical-lens diagnostics. - These results constitute, to our knowledge, the first comprehensive experimental demonstration of deep-UV high-OAM beams generated with fabricated DOEs and validated through mode-conversion measurements. The demonstrated techniques are compatible with high-power UV laser systems used in RF-photoinjectors and offer a practical route toward structured photocathode illumination and the generation of relativistic vortex electrons at a particle accelerator facility. - oai:arXiv.org:2512.08442v1 + Two-Photon Bandwidth of Hyper-Entangled Photons in Complex Media + https://arxiv.org/abs/2512.09456 + arXiv:2512.09456v1 Announce Type: cross +Abstract: When light propagates through complex media, its output spatial distribution is highly sensitive to its wavelength. This fundamentally limits the bandwidth of applications ranging from imaging to communication. Here, we demonstrate analytically and numerically that the spatial correlations of hyper-entangled photon pairs, simultaneously entangled spatially and spectrally, remain stable across a broad bandwidth: The chromatic modal dispersion experienced by one photon is canceled to first order by its spectrally anti-correlated twin, defining a "two-photon bandwidth" that can far exceed its classical counterpart. We illustrate this modal dispersion cancellation in multimode fibers, thin diffusers and blazed gratings, and demonstrate its utility for broadband wavefront shaping of quantum states. These findings advance our fundamental understanding of quantum light in complex media with applications in quantum imaging, communication, and sensing. + oai:arXiv.org:2512.09456v1 quant-ph - physics.acc-ph physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - A. S. Dyatlov, D. M. Dolgintsev, V. V. Gerasimov, V. V. Kobets, V. P. Nazmov, M. A. Nozdrin, A. N. Sergeev, D. S. Shokin, K. E. Yunenko, D. V. Karlovets + Ronen Shekel, Ohad Lib, S\'ebastien M. Popoff, Yaron Bromberg - Photon Dynamics and Collision Risks in Relativistic Spaceflight: A Comparative Study of Methods and Implications - https://arxiv.org/abs/2512.08447 - arXiv:2512.08447v1 Announce Type: cross -Abstract: This dissertation explores the dynamics of relativistic spaceflight, focusing on the risks associated with collisions and photon interactions as a spacecraft approaches velocities near the speed of light. The study emphasizes two primary collision types: (1) collisions with interstellar dust and particles, and (2) interactions with cosmic molecules, specifically hydrogen. Using principles of energy conservation and relativistic mechanics, the energy transfer from these collisions is calculated, showing that even small particles can impart massive energy at relativistic speeds. The dissertation also examines the impact of the cosmic microwave background (CMB) radiation, particularly its blue-shifting effect at high velocities, which influences photon interactions with the spacecraft. Additionally, the Schwinger limit, which sets an upper bound on the electromagnetic field strength for sustained relativistic travel, is discussed in the context of photon-induced pair production. Lastly, advanced photon interactions, such as Compton scattering, are analyzed for their role in thermal management and spacecraft design. The findings highlight the importance of shielding, thermal regulation, and collision avoidance strategies in the design of spacecraft for interstellar travel, offering insights into the potential challenges and solutions for achieving relativistic spaceflight. - oai:arXiv.org:2512.08447v1 - astro-ph.HE - gr-qc - physics.space-ph - Wed, 10 Dec 2025 00:00:00 -0500 + The Complex-Step Integral Transform + https://arxiv.org/abs/2512.09459 + arXiv:2512.09459v1 Announce Type: cross +Abstract: Building on the well-established connection between the Hilbert transform and derivative operators, and motivated by recent developments in complex-step differentiation, we introduce the Complex-Step Integral Transform (CSIT): a generalized integral transform that combines analytic continuation, derivative approximation, and multi-scale smoothing within a unified framework. A spectral analysis shows that the CSIT preserves phase while suppressing high-wavenumber noise, offering advantages over conventional Fourier derivatives. We discuss the roles of the real and imaginary step parameters, compare FFT-based and interpolation-based implementations, and demonstrate the method on the advection equation and instantaneous-frequency computation. Results show that the CSIT yields smoother, more robust attributes than Hilbert-based methods and provides built-in stabilization for PDE solvers. The CSIT thus represents a flexible alternative for numerical differentiation, spectral analysis, and seismic signal processing. The method opens several avenues for future work, including non-periodic implementations, adaptive parameter selection, and integration with local interpolation frameworks such as high-order Finite-Element methods. + oai:arXiv.org:2512.09459v1 + math.NA + cs.NA + physics.geo-ph + Thu, 11 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - Li Kai Wen, Joao Rodrigues - - - Single-Particle X-ray Scattering Reveals a High Local Supersaturation of Precursors as the Origin of CoO Assembly Formation - https://arxiv.org/abs/2512.08488 - arXiv:2512.08488v1 Announce Type: cross -Abstract: Single-particle small-angle X-ray scattering (SP-SAXS) enables quantitative morphological analysis by recording diffraction snapshots from isolated particles using X-ray free-electron laser (XFEL) pulses. Unlike conventional X-ray techniques, which average over the entire illuminated sample volume, SP-SAXS resolves low-contrast, less abundant, or transient species within heterogeneous particle populations that would otherwise remain hidden. Here, we apply SP-SAXS to investigate the solvothermal formation of CoO nanocrystal assemblies from a Co(acac)$_3$ precursor in benzyl alcohol. The single-particle data reveal amorphous, uniform-density Co(acac)$_2$ spheres as transient intermediates that directly crystallize into cavernous CoO nanocrystal assemblies, which explains why CoO forms as hierarchical aggregates rather than as isolated nanocrystals. These results demonstrate that SP-SAXS provides a powerful framework for disentangling morphological heterogeneity in nanoparticle formation processes. - oai:arXiv.org:2512.08488v1 - cond-mat.mes-hall - cond-mat.mtrl-sci - physics.data-an - Wed, 10 Dec 2025 00:00:00 -0500 - cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Sani Y. Harouna-Mayer, Lars Klemeyer, Cecilia A. Zito, Johan Bielecki, Xuemei Cheng, Davide Derelli, Armando D. Estillore, Tjark L. R. Groene, Lukas V. Haas, Romain Letrun, Chan Kim, Jayanath C. P. Koliyadu, Abhishek Mall, Parichita Mazumder, Diogo V. M. Melo, Adam R. Round, Amit K. Samanta, Abhisakh Sarma, Zhou Shen, Xiao Sun, Patrik Vagovic, Tamme Wollweber, Richard Bean, Jochen K\"upper, Henry N. Chapman, Dorota Koziej, Kartik Ayyer + Rafael Abreu, Stephanie Durand, Jochen Kamm, Christine Thomas, Monika Pandey - Tunable passive squeezing of squeezed light through unbalanced double homodyne detection - https://arxiv.org/abs/2512.08540 - arXiv:2512.08540v1 Announce Type: cross -Abstract: The full characterization of quantum states of light is a central task in quantum optics and information science. Double homodyne detection provides a powerful method for the direct measurement of the Husimi Q quasi-probability distribution, offering a complete state representation in a simple experimental setting and a limited time frame. Here, we demonstrate that double homodyne detection can serve as more than a passive measurement apparatus. By intentionally unbalancing the input beamsplitter that splits the quantum signal, we show that the detection scheme itself performs an effective squeezing or anti-squeezing transformation on the state being measured. The resulting measurement directly samples the Q function of the input state as if it were acted upon by a squeezing operator whose strength is a tunable experimental parameter : the beamsplitter's reflectivity. We experimentally realize this technique using a robust polarization-encoded double homodyne detection to characterize a squeezed vacuum state. Our results demonstrate the controlled deformation of the measured Q function's phase-space distribution, confirming that unbalanced double homodyne detection is a versatile tool for simultaneous quantum state manipulation and characterization. - oai:arXiv.org:2512.08540v1 - quant-ph - physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + Scalable Construction of Spiking Neural Networks using up to thousands of GPUs + https://arxiv.org/abs/2512.09502 + arXiv:2512.09502v1 Announce Type: cross +Abstract: Diverse scientific and engineering research areas deal with discrete, time-stamped changes in large systems of interacting delay differential equations. Simulating such complex systems at scale on high-performance computing clusters demands efficient management of communication and memory. Inspired by the human cerebral cortex -- a sparsely connected network of $\mathcal{O}(10^{10})$ neurons, each forming $\mathcal{O}(10^{3})$--$\mathcal{O}(10^{4})$ synapses and communicating via short electrical pulses called spikes -- we study the simulation of large-scale spiking neural networks for computational neuroscience research. This work presents a novel network construction method for multi-GPU clusters and upcoming exascale supercomputers using the Message Passing Interface (MPI), where each process builds its local connectivity and prepares the data structures for efficient spike exchange across the cluster during state propagation. We demonstrate scaling performance of two cortical models using point-to-point and collective communication, respectively. + oai:arXiv.org:2512.09502v1 + cs.DC + cs.NE + physics.comp-ph + q-bio.NC + Thu, 11 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - Niels Tripier-Mondancin, David Barral, Gana\"el Roeland, Ra\'ul Leonardo Rincon Celis, Yann Bouchereau, Nicolas Treps + Bruno Golosio, Gianmarco Tiddia, Jos\'e Villamar, Luca Pontisso, Luca Sergi, Francesco Simula, Pooja Babu, Elena Pastorelli, Abigail Morrison, Markus Diesmann, Alessandro Lonardo, Pier Stanislao Paolucci, Johanna Senk - Transcript-based estimators for characterizing interactions - https://arxiv.org/abs/2512.08570 - arXiv:2512.08570v1 Announce Type: cross -Abstract: The concept of transcripts was introduced in 2009 as a means to characterize various aspects of the functional relationship between time series of interacting systems. Based on this concept that utilizes algebraic relations between ordinal patterns derived from time series, estimators for the strength, direction, and complexity of interactions have been introduced. These estimators, however, have not yet found widespread application in studies of interactions between real-world systems. Here, we revisit the concept of transcripts and showcase the usage of transcript-based estimators for a time-series-based investigation of interactions between coupled paradigmatic dynamical systems of varying complexity. At the example of a time-resolved analysis of multichannel and multiday recordings of ongoing human brain dynamics, we demonstrate the potential of the methods to provide novel insights into the intricate spatial-temporal interactions in the human brain underlying different vigilance states. - oai:arXiv.org:2512.08570v1 - nlin.CD - physics.data-an - Wed, 10 Dec 2025 00:00:00 -0500 + Ultimate large-$Rm$ regime of the solar dynamo + https://arxiv.org/abs/2512.09536 + arXiv:2512.09536v1 Announce Type: cross +Abstract: For more than fourty years, the quest to understand how large-scale magnetic fields emerge from turbulent flows in rotating astrophysical systems, such as the Sun, has been a major thread of computational astrophysics research. Using a parameter scan and phenomenological analysis of maximally-simplified three-dimensional cartesian magnetohydrodynamic simulations of large-scale nonlinear helical turbulent dynamos, I present results in this Letter that strongly point to an asymptotic ultimate regime of the large-scale solar dynamo, at large magnetic Reynolds numbers $Rm$, involving helicity fluxes between hemispheres. I obtained corresponding numerical solutions at both $Pm>1$ and $Pm<1$, and show that they can currently only be achieved in clean, simplified numerical setups. The analysis further strongly suggests that all global simulations to date lie in a non-asymptotic turbulent MHD regimes highly sensitive to changes in kinetic and magnetic Reynolds numbers. Ideas are presented to attempt to reach this ultimate regime in such "realistic" global spherical models at a reasonable numerical cost. Overall, the results clarify the current state, and some hard limitations of the brute-force numerical modelling approach applied to this, and other similar astrophysical turbulence problems. + oai:arXiv.org:2512.09536v1 + astro-ph.SR + astro-ph.GA + physics.flu-dyn + physics.plasm-ph + Thu, 11 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - Manuel Adams, Jos\'e M. Amig\'o, Klaus Lehnertz + Fran\c{c}ois Rincon (IRAP, CNRS, UPS) - $\mathcal{PT}$-symmetric cavity magnomechanics with gain-assisted transparency and amplification - https://arxiv.org/abs/2512.08612 - arXiv:2512.08612v1 Announce Type: cross -Abstract: We investigate magnomechanically induced transparency in a parity-time-symmetric cavity magnomechanical system with traveling-field-induced non-Hermiticity. The setup consists of a microwave cavity mode coupled to magnons in a single-crystal yttrium iron garnet sphere, which in turn are hybridized with a vibrational mechanical mode through magnetostrictive interaction. In the Hermitian regime, strong photon-magnon coupling generates a single transparency window in the cavity transmission, which splits into a doublet when the magnon is coherently hybridized with the mechanical mode via magnomechanical coupling. This establishes a versatile platform in which the transparency spectrum can be engineered from single- to multi-window response using experimentally accessible, scaled magnomechanical interactions. When a non-Hermitian coupling is introduced, the system enters a parity-time-broken regime in which the transparency ceases to be purely passive and becomes gain assisted, leading to asymmetric transmission with amplification on one side of the resonance and enhanced absorption on the other. By tuning the cavity detuning, we convert magnomechanical transparency into Fano-type line shapes with strongly non-Lorentzian phase dispersion and map their deformation into asymmetric, gain-assisted Fano ridges in the joint space of probe and magnon detunings. Finally, we analyze the associated group delay and show that both slow- and fast-light behavior can be widely tuned by varying the photon-magnon and magnomechanical couplings together with the non-Hermitian strength, highlighting parity-time-symmetric cavity magnomechanics as a promising platform for reconfigurable quantum signal processing and enhanced sensing. - oai:arXiv.org:2512.08612v1 - quant-ph - math-ph - math.MP - physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + High-throughput characterization of snap-through stability boundaries of bistable beams in a programmable rotating platform + https://arxiv.org/abs/2512.09544 + arXiv:2512.09544v1 Announce Type: cross +Abstract: We introduce a high-throughput platform that enables simultaneous, parallel testing of six bistable beams via programmable motion of a rotating disk. By prescribing harmonic angular dynamics, the platform explores the phase space of angular velocity and acceleration $(\Omega,\,\dot{\Omega})$, producing continuously varying centrifugal and Euler force fields that act as tunable body forces in our specimens. Image processing extracts beam kinematics with sub-pixel accuracy, enabling precise identification of snap-through events. By testing six beams in parallel, the platform allows systematic variation of beam thickness, pre-compression, tilt angle, and clamp orientations across 65 distinct configurations, generating 23,400 individual experiments. We construct stability boundaries and quantitatively parameterize them as parabolic functions, characterized by a vertical offset and a curvature parameter. Tilt angle provides the most robust mechanism for tuning the curvature parameter, while beam thickness and pre-compression modulate vertical offset. Modal decomposition analysis reveals that antisymmetric clamp configurations can trigger mode switching, in which competing geometric and inertial effects drive transitions through different deformation pathways. Our work establishes a scalable experimental framework for high-throughput characterization of dynamic nonlinear instabilities in mechanics. The complete experimental dataset is made publicly available to support data-driven design and machine learning models for nonlinear mechanics with applications to bistability-based metamaterials, mechanical memory, and electronics-free sensing systems. + oai:arXiv.org:2512.09544v1 + cond-mat.soft + physics.class-ph + Thu, 11 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - Cham Oumie, Wu-Ming Liu, Kashif Ammar Yasir + Eduardo Gutierrez-Prieto, Gilad Yakir, Pedro M. Reis - Nonequilibrium Photocarrier and Phonon Dynamics from First Principles: a Unified Treatment of Carrier-Carrier, Carrier-Phonon, and Phonon-Phonon Scattering - https://arxiv.org/abs/2512.08618 - arXiv:2512.08618v1 Announce Type: cross -Abstract: We develop a first-principles many-body framework to describe the dynamics of photocarriers and phonons in semiconductors following ultrafast excitation. Our approach incorporates explicit ab initio light-matter coupling and first-principles collision integrals for carrier-carrier, carrier-phonon, and phonon-phonon scattering. It also yields time-dependent quasiparticle and phonon frequency renormalizations, along with light-induced coherent atomic motion. The equations of motion are solved in a maximally localized Wannier basis, ensuring gauge-consistent scattering integrals and ultradense momentum sampling, thereby enabling direct comparison with pump-probe experiments. The method can be coupled to constrained density-functional theory to access light-induced structural phase transitions at longer times after the light pulse. We showcase the capabilities and predictive power of this framework on MoS$_2$ and h-BN monolayers. For MoS$_2$, we resolve photoinduced renormalizations of electronic and lattice properties, ultrafast carrier relaxation, hot-phonon dynamics, and displacive coherent atomic motion. Including carrier-carrier scattering is crucial to obtain realistic photocarrier equilibration times, while omitting phonon-phonon scattering leads to incorrect long-time lattice thermalization and a factor of two larger A$_{1g}$ coherent phonon damping time. For h-BN, we quantify photoinduced changes in the electronic, optical, and lattice responses in quasi-equilibrium, demonstrating a fluence-dependent enhancement of screening and melting of excitonic features. - oai:arXiv.org:2512.08618v1 + Checkerboard-type Zhang-Rice States in Overdoped Cuprate Superconductors + https://arxiv.org/abs/2512.09547 + arXiv:2512.09547v1 Announce Type: cross +Abstract: Cuprate superconductors remain central to condensed matter physics due to their technological relevance and unconventional, incompletely understood electronic behavior. While the canonical phase diagram and low-energy models have been shaped largely by studies of underdoped and moderately doped cuprates, the overdoped regime has received comparatively limited attention.Here, we track the evolution of the electronic structure from optimal to heavy overdoping in La2-xSrxCuO4(LSCO) using broadband optical spectroscopy across x=0.15-0.60. The measured spectral changes--including the redistribution of Zhang-Rice-related spectral weigh--are in qualitative agreement with determinant quantum Monte Carlo simulations of the three-orbital Emery model, which together indicate a pronounced reconstruction of the electronic structure beyond hole concentrations x>0.2. Guided by these observations, we propose a spontaneous checkerboard-type Zhang-Rice electronic configuration that captures the coexistence of itinerant and localized carriers characteristic of the heavily overdoped state. Our results refine the doping-dependent Zhang-Rice-based framework for cuprates, illuminate how correlations persist deep into the overdoped regime, and provide new constraints on microscopic mechanisms of high-temperature superconductivity, with broader implications for correlated transition-metal oxides. + oai:arXiv.org:2512.09547v1 + cond-mat.supr-con cond-mat.mtrl-sci - physics.comp-ph - Wed, 10 Dec 2025 00:00:00 -0500 + physics.app-ph + Thu, 11 Dec 2025 00:00:00 -0500 cross - http://creativecommons.org/licenses/by/4.0/ - Stefano Mocatti, Giovanni Marini, Giulio Volpato, Pierluigi Cudazzo, Matteo Calandra + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Xiongfang Liu, Kun Han, Yan Peng, Yuanjie Ning, Jing Wu, Zhaoyang Luo, Difan Zhou, Zhigang Zeng, Qian He, Chuanbing Cai, Mark. B. H. Breese, Ariando Ariando, Chi Sin Tang, George A. Sawatzky, Mi Jiang, Xinmao Yin - Strain sensitivity enhancement in a Grover-Michelson interferometer - https://arxiv.org/abs/2512.08638 - arXiv:2512.08638v1 Announce Type: cross -Abstract: The Michelson interferometric phase detection resolution can be enhanced by replacing conventional beam splitters with novel directionally unbiased four-port scatterers, such as Grover coins. We present a quantitative analysis of the noise-to-signal ratio of sideband frequencies generated by gravitational wave-induced phase perturbations in a Grover-Michelson interferometer (GMI). We discuss the principles of GMI signal enhancement and demonstrate how combining this configuration with additional light-recycling arrangements further enhances the performance. - oai:arXiv.org:2512.08638v1 + Can Intense Quantum Light Beat Classical Uncertainty Relations? + https://arxiv.org/abs/2512.09558 + arXiv:2512.09558v1 Announce Type: cross +Abstract: Uncertainty relations are fundamental to quantum mechanics, encoding limits on the simultaneous measurement of conjugate observables. Violations of joint uncertainty bounds can certify entanglement -- a resource critical for quantum information protocols and increasingly relevant in strong-field physics. Here, we investigate the pairwise time-delay and frequency-bandwidth uncertainties for arbitrary multimode quantum states of light, deriving a general lower bound for their joint product. We find that the nonclassical correction scales inversely with the average photon number, a behavior rooted in the so-called ``monogamy of entanglement''. These results clarify the intensity scaling of quantum advantages in nonclassical light states and highlight the interplay between entanglement and photon statistics. + oai:arXiv.org:2512.09558v1 quant-ph physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 cross - http://creativecommons.org/licenses/by/4.0/ - 10.1103/8h71-w8tt - Manni, A., Schwarze, C., Simon, D., Ndao, A., & Sergienko, A. (2025). Strain sensitivity enhancement in a Grover-Michelson interferometer. Phys. Rev. D, 112, 122002 - Anthony D. Manni, Christopher R. Schwarze, David S. Simon, Abdoulaye Ndao, Alexander V. Sergienko + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Felipe Reibnitz Willemann, Mauro Antezza, Johannes Feist + + + Seeing Soil from Space: Towards Robust and Scalable Remote Soil Nutrient Analysis + https://arxiv.org/abs/2512.09576 + arXiv:2512.09576v1 Announce Type: cross +Abstract: Environmental variables are increasingly affecting agricultural decision-making, yet accessible and scalable tools for soil assessment remain limited. This study presents a robust and scalable modeling system for estimating soil properties in croplands, including soil organic carbon (SOC), total nitrogen (N), available phosphorus (P), exchangeable potassium (K), and pH, using remote sensing data and environmental covariates. The system employs a hybrid modeling approach, combining the indirect methods of modeling soil through proxies and drivers with direct spectral modeling. We extend current approaches by using interpretable physics-informed covariates derived from radiative transfer models (RTMs) and complex, nonlinear embeddings from a foundation model. We validate the system on a harmonized dataset that covers Europes cropland soils across diverse pedoclimatic zones. Evaluation is conducted under a robust validation framework that enforces strict spatial blocking, stratified splits, and statistically distinct train-test sets, which deliberately make the evaluation harder and produce more realistic error estimates for unseen regions. The models achieved their highest accuracy for SOC and N. This performance held across unseen locations, under both spatial cross-validation and an independent test set. SOC obtained a MAE of 5.12 g/kg and a CCC of 0.77, and N obtained a MAE of 0.44 g/kg and a CCC of 0.77. We also assess uncertainty through conformal calibration, achieving 90 percent coverage at the target confidence level. This study contributes to the digital advancement of agriculture through the application of scalable, data-driven soil analysis frameworks that can be extended to related domains requiring quantitative soil evaluation, such as carbon markets. + oai:arXiv.org:2512.09576v1 + cs.CV + physics.geo-ph + Thu, 11 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by-nc-nd/4.0/ + David Seu (CO2 Angels, Cluj-Napoca, Romania), Nicolas Longepe (European Space Agency Phi-Lab, Frascati, Italy), Gabriel Cioltea (CO2 Angels, Cluj-Napoca, Romania), Erik Maidik (CO2 Angels, Cluj-Napoca, Romania), Calin Andrei (CO2 Angels, Cluj-Napoca, Romania) - Perfect continuous-variable quantum microcombs - https://arxiv.org/abs/2512.08650 - arXiv:2512.08650v1 Announce Type: cross -Abstract: Quantum microcombs generated in high-Q microresonators provide compact, multiplexed sources of entangled modes for continuous-variable (CV) quantum information processing. While deterministic generation of CV states via Kerr-induced two-mode squeezing has been demonstrated, achieving spectrally uniform squeezing remains challenging because of asymmetry and anomalies in the dispersion profile. Here we overcome these limitations by combining a microresonator with an engineered mode spectrum and optimized pump conditions. We realize a CV quantum microcomb comprising 14 independent two-mode squeezed states, each exhibiting more than 4 dB of raw squeezing (up to 4.3 dB) across a 0.7 THz bandwidth. This uniform, high-performance quantum resource represents a key step toward scalable, integrated CV quantum technologies operating beyond classical limits. - oai:arXiv.org:2512.08650v1 + Exceptional points of arbitrary high orders induced by non-Markovian dynamics + https://arxiv.org/abs/2512.09582 + arXiv:2512.09582v1 Announce Type: cross +Abstract: Exceptional points are singularities in the spectrum of non-Hermitian systems in which several eigenvectors are linearly dependent and their eigenvalues are equal to each other. Usually it is assumed that the order of the exceptional point is limited by the number of degrees of freedom of a non-Hermitian system. In this letter, we refute this common opinion and show that non-Markovian effects can lead to dynamics characteristic of systems with exceptional points of higher orders than the number of degrees of freedom in the system. This takes place when the energy returns from reservoir to the system such that the dynamics of the system are divided into intervals in which it describes by the product of the exponential and a polynomial function of ever-increasing order. We demonstrate that by choosing the observation time, it is possible to observe exceptional points of arbitrary high orders. + oai:arXiv.org:2512.09582v1 quant-ph physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Kangkang Li, Yue Wang, Ze Wang, Xin Zhou, Jincheng Li, Yinke Cheng, Binyan Wu, Qihuang Gong, Bei-Bei Li, Qi-Fan Yang + Timofey T. Sergeev, Evgeny S. Andrianov, Alexander A. Zyablovsky - Spectroscopic readout of chiral photonic topology in a single-cavity spin-orbit-coupled Bose-Einstein condensate - https://arxiv.org/abs/2512.08662 - arXiv:2512.08662v1 Announce Type: cross -Abstract: Topological photonic phases are typically identified through band reconstruction, steady-state transmission, or real-space imaging of edge modes. In this work, we present a framework for spectroscopic readout of chiral photonic topology in a single driven optical cavity containing a spin-orbit-coupled Bose-Einstein condensate. We demonstrate that the cavity transmission power spectral density provides a direct and measurable proxy for a momentum- and frequency-resolved photonic Chern marker, enabling topological characteristics to be inferred from spectral data without the need for bulk-band tomography. In the loss-dominated regime, where cavity decay exceeds atomic dissipation, the power spectral density exhibits Dirac-like gapped hybrid modes with a vanishing Chern marker, indicating a trivial phase. When the dissipation imbalance is reversed, a bright, gap-spanning spectral ridge emerges, co-localized with peaks in both the Chern marker and Berry curvature. The complex spectrum reveals parity-time symmetric coalescences and gain-loss bifurcations, marking exceptional points and enabling chiral, gap-traversing transport. By linking noise spectroscopy to geometric and non-Hermitian topology in a minimal cavity-QED architecture, this work provides a framework for spectroscopic detection of topological order in driven quantum systems. This approach offers a pathway to compact, tunable topological photonics across a broad range of light-matter platforms, providing a method for the study and control of topological phases in hybrid quantum systems. - oai:arXiv.org:2512.08662v1 - quant-ph - cond-mat.quant-gas + SiNx RRAMs performance with different stoichiometries + https://arxiv.org/abs/2512.09677 + arXiv:2512.09677v1 Announce Type: cross +Abstract: The microstructure of SiNx is strongly affected by its stoichiometry, x. The stoichiometry of SiNx thin films can be modified by adjusting the gas flow rates during LPCVD deposition. The deficiency or excess of Si atoms enhance the formation of defects such as nitrogen vacancies, silicon dangling bonds etc., and thus can enable performance tuning of the resulting MIS RRAM devices. DC electrical characterization, impedance spectroscopy and constant voltage stress measurements were carried out to investigate the properties of non-stoichiometric silicon nitride films as resistive switching material. The average SET time for each device was measured by applying voltage ramps. Improvement in the SET/RESET voltages and SET time is observed. Finally, the stoichiometric film exhibits the lowest breakdown acceleration factor, while the Si-rich film the highest. + oai:arXiv.org:2512.09677v1 + cond-mat.mtrl-sci physics.app-ph - physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/publicdomain/zero/1.0/ + 10.1016/j.sse.2025.109252 + A. E. Mavropoulis, G. Pissanos, N. Vasileiadis, P. Normand, G. Ch. Sirakoulis, P. Dimitrakis + + + Breakdown characteristics of SiNx with different stoichiometries for resistive memories + https://arxiv.org/abs/2512.09681 + arXiv:2512.09681v1 Announce Type: cross +Abstract: The breakdown characteristics of SiNx layers with different stoichiometries are explored. The stoichiometry of SiNx is modified by changing the gas flow rates during the LPCVD deposition. These layers are suitable for RRAM cells. + oai:arXiv.org:2512.09681v1 + cond-mat.mtrl-sci + physics.app-ph + Thu, 11 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/publicdomain/zero/1.0/ + 10.1109/NMDC64551.2025.11234186 + A. E. Mavropoulis, I. Kanellopoulos, G. Pissanos, G. Samara, N. Vasileiadis, E. Stavroulakis, P. Normand, G. Ch. Sirakoulis, P. Dimitrakis + + + Resistance Switching Properties of Stoichiometric and Nitrogen Implanted Silicon Nitride Nanolayers on N and P-Type Si Substrates + https://arxiv.org/abs/2512.09684 + arXiv:2512.09684v1 Announce Type: cross +Abstract: This paper examines the resistive switching characteristics of LPCVD SiNx MNOS ReRAM cells on both heavily doped n- and p-type silicon substrates, focusing on the effects of nitrogen doping. Detailed comparisons of electrical properties through nitrogen implantation reveal variations in trap density and SET-RESET voltages between n and p conductivity Si substrates. Impedance spectroscopy further elucidates the conductive path formation and its resistance. + oai:arXiv.org:2512.09684v1 + cond-mat.mtrl-sci + physics.app-ph + Thu, 11 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/publicdomain/zero/1.0/ + 10.1109/NANO63165.2025.11113675 + A. E. Mavropoulis, P. Karakolis, N. Vasileiadis, L. Sygellou, E. Stavroulakis, V. Ioannou-Sougleridis, P. Normand, G. Ch. Sirakoulis, P. Dimitrakis + + + Molecular Dynamics Simulations of $\gamma$-Belite(010)-Water Interfaces with High-Dimensional Neural Network Potentials + https://arxiv.org/abs/2512.09702 + arXiv:2512.09702v1 Announce Type: cross +Abstract: Belite -- dicalcium silicate Ca$_2$SiO$_4$ -- is a main constituent of low-carbon cement. In this work, we study several terminations of the (010) surface of $\gamma$-belite, its most stable polymorph, by molecular dynamics simulations. The energies and forces are provided by a high-dimensional neural network potential trained to density functional theory data. Water can interact in molecular form as well as dissociatively with the investigated interfaces, and the degree of dissociation is determined primarily by the protonation of SiO$_4$ groups accessible at the surface. A major part of the simultaneously formed hydroxide ions is adsorbed at surface calcium atoms, whose octahedral coordination spheres are completed by additional water molecules. The T3 termination, which is most stable in vacuum, shows only little reactivity in water. For the only slightly less stable T2 termination, however, two distinct types of surface defects are observed. The type I defect is even stable in vacuum and leads to a reconstruction of the entire surface, while the type II defect is only found in the presence of water. Overall, our results suggest that a variety of structures may be formed at the Ca$_2$SiO$_4$(010) surface, which are stabilized in the presence of water. + oai:arXiv.org:2512.09702v1 + cond-mat.mtrl-sci + physics.chem-ph + Thu, 11 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Bernadeta Prus, J\"org Behler + + + Structural Optimization in Tensor LEED Using a Parameter Tree and $R$-Factor Gradients + https://arxiv.org/abs/2512.09737 + arXiv:2512.09737v1 Announce Type: cross +Abstract: Quantitative low-energy electron diffraction [LEED $I(V)$] is a powerful method for surface-structure determination, based on a direct comparison of experimentally observed $I(V)$ data with computations for a structure model. As the diffraction intensities $I$ are highly sensitive to subtle structural changes, local structure optimization is essential for assessing the validity of a structure model and finding the best-fit structure. The calculation of diffraction intensities is well established, but the large number of evaluations required for reliable structural optimization renders it computationally demanding. The computational effort is mitigated by the tensor-LEED approximation, which accelerates optimization by applying a perturbative treatment of small deviations from a reference structure. Nevertheless, optimization of complex structures is a tedious process. + Here, the problem of surface-structure optimization is reformulated using a tree-based data structure, which helps to avoid redundant function evaluations. In the new tensor-LEED implementation presented in this work, intensities are computed on the fly, eliminating limitations of previous algorithms that are limited to precomputed values at a grid of search parameters. It also enables the use of state-of-the-art optimization algorithms. Implemented in \textsc{Python} with the JAX library, the method provides access to gradients of the $R$ factor and supports execution on graphics processing units (GPUs). Based on these developments, the computing time can be reduced by more than an order of magnitude. + oai:arXiv.org:2512.09737v1 + cond-mat.mtrl-sci + physics.comp-ph + physics.data-an + Thu, 11 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - Kashif Ammar Yasir, Gao Xianlong + Alexander M. Imre, Paul Haidegger, Florian Kraushofer, Ralf Wanzenb\"ock, Tobias Hable, Sarah Tobisch, Marie Kienzer, Florian Buchner, Jes\'us Carrete, Georg K. H. Madsen, Michael Schmid, Ulrike Diebold, Michele Riva - Many interacting particles in solution. II. Screening-ranged expansion of electrostatic forces - https://arxiv.org/abs/2512.08682 - arXiv:2512.08682v1 Announce Type: cross -Abstract: We present a fully analytical integration of the Maxwell stress tensor and derive exact relations for interparticle forces in systems of multiple dielectric spheres immersed in a polarizable ionic solvent, within the framework of the linearized Poisson--Boltzmann theory. Building upon the screening-ranged (in ascending orders of Debye screening) expansions of the potentials developed and rigorously analyzed in the accompanying works \cite{supplem_pre,supplem_pre_math,supplem_prl}, we construct exact screening-ranged many-body expansions for electrostatic forces in explicit analytical form. These results establish a rigorous foundation for evaluating screened electrostatic interactions in complex particle systems and provide direct analytical connections to, and systematic improvements upon, various earlier approximate or limited-case formulations available in the literature, both at zero and finite ionic strength. - oai:arXiv.org:2512.08682v1 - cond-mat.soft - math-ph - math.MP - physics.bio-ph + Predicting CME Arrivals with Heliospheric Imagers from L5: A Data Assimilation Approach + https://arxiv.org/abs/2512.09738 + arXiv:2512.09738v1 Announce Type: cross +Abstract: The Solar TErrestrial RElations Observatory (STEREO) mission has laid a foundation for advancing real-time space weather forecasting by enabling the evaluation of heliospheric imager (HI) data for predicting coronal mass ejection (CME) arrivals at Earth. This study employs the ELEvoHI model to assess how incorporating STEREO/HI data from the Lagrange 5 (L5) perspective can enhance prediction accuracy for CME arrival times and speeds. Our investigation, preparing for the upcoming ESA Vigil mission, explores whether the progressive incorporation of HI data in real-time enhances forecasting accuracy. The role of human tracking variability is evaluated by comparing predictions based on observations by three different scientists, highlighting the influence of manual biases on forecasting outcomes. Furthermore, the study examines the efficacy of deriving CME propagation directions using HI-specific methods versus coronagraph-based techniques, emphasising the trade-offs in prediction accuracy. Our results demonstrate the potential of HI data to significantly improve operational space weather forecasting when integrated with other observational platforms, especially when HI data from beyond 35{\deg} elongation are used. These findings pave the way for optimising real-time prediction methodologies, providing valuable groundwork for the forthcoming Vigil mission and enhancing preparedness for CME-driven space weather events. + oai:arXiv.org:2512.09738v1 + astro-ph.SR + physics.space-ph + Thu, 11 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Tanja Amerstorfer, Justin Le Lou\"edec, David Barnes, Maike Bauer, Jackie A. Davies, Satabdwa Majumdar, Eva Weiler, Christian M\"ostl + + + Rotational excitation of molecules in the regime of strong ro-vibrational coupling: Comparison between an optical centrifuge and a transform-limited pulse + https://arxiv.org/abs/2512.09746 + arXiv:2512.09746v1 Announce Type: cross +Abstract: We investigate theoretically the ability of an optical centrifuge - a laser pulse whose linear polarization is rotating at an accelerated rate, to control molecular rotation in the regime when the rigid-rotor approximation breaks down due to coupling between the vibrational and rotational degrees of freedom. Our analysis demonstrates that the centrifuge field enables controlled excitation of high rotational states while maintaining relatively low spread along the vibrational coordinate. We contrast this to the rotational excitation by a linearly polarized Gaussian pulse of equal spectral width and pulse energy which, although comparable to the centrifuge-induced rotation, is unavoidably accompanied by a substantial broadening of the vibrational wavepacket. + oai:arXiv.org:2512.09746v1 + quant-ph + physics.atom-ph physics.chem-ph physics.comp-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Sergii V. Siryk, Walter Rocchia + http://creativecommons.org/licenses/by/4.0/ + J. M. Garc\'ia-Garrido, V. Milner, C. P. Koch, R. Gonz\'alez-F\'erez - Many interacting particles in solution. III. Spectral analysis of the associated Neumann--Poincar\'e-type operators - https://arxiv.org/abs/2512.08684 - arXiv:2512.08684v1 Announce Type: cross -Abstract: The interaction of particles in an electrolytic medium can be calculated by solving the Poisson equation inside the solutes and the linearized Poisson--Boltzmann equation in the solvent, with suitable boundary conditions at the interfaces. Analytical approaches often expand the potentials in spherical harmonics, relating interior and exterior coefficients and eliminating some coefficients in favor of others, but a rigorous spectral analysis of the corresponding formulations is still lacking. Here, we introduce composite many-body Neumann--Poincar\'e-type operators and prove that they are compact with spectral radii strictly less than one. These results provide the foundation for systematic screening-ranged expansions, in powers of the Debye screening parameters, of electrostatic potentials, interaction energies, and forces, and establish the analytical framework for the accompanying works~\cite{supplem_prl,supplem_pre,supplem_pre_force}. - oai:arXiv.org:2512.08684v1 - cond-mat.soft + Origins of Instability in Dynamical Systems on Undirected Networks + https://arxiv.org/abs/2512.09765 + arXiv:2512.09765v1 Announce Type: cross +Abstract: Robustness to perturbation is a key topic in the study of complex systems occurring across a wide variety of applications from epidemiology to biochemistry. Here we analyze the eigenspectrum of the Jacobian matrices associated to a general class of networked dynamical systems, which contains information on how perturbations to a stationary state develop over time. We find that stability is always determined by a spectral outlier, but with pronounced differences to the corresponding eigenvector in different regimes. We show that, depending on model details, instability may originate in nodes of anomalously low or high degree, or may occur everywhere in the network at once. Importantly, the dependence on extremal degrees results in considerable finite-size effects with different scaling depending on the ensemble degree distribution. Our results have potentially useful applications in network monitoring to predict or prevent catastrophic failures, and we validate our analytical findings through applications to epidemic dynamics and gene regulatory systems. + oai:arXiv.org:2512.09765v1 + nlin.AO math-ph math.MP physics.bio-ph - physics.chem-ph - physics.comp-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Sergii V. Siryk, Walter Rocchia + http://creativecommons.org/licenses/by/4.0/ + Shraosi Dawn, Subrata Ghosh, Chandrakala Meena, Tim Rogers, Chittaranjan Hens - Two-phase hydrodynamic model of active colloid motion - https://arxiv.org/abs/2512.08744 - arXiv:2512.08744v1 Announce Type: cross -Abstract: The paper presents a two-phase hydrodynamic model for the numerical simulation of collective motion in a thin layer of active colloids containing spherical microswimmers. The model accounts for three fundamental mechanisms governing the dynamics of the active colloid: the random motion of the microswimmers, their mutual collisions, and their interaction with the surrounding fluid phase. The accurate resolution of the characteristic time scales associated with each mechanism is crucial for reproducing the different dynamic modes. The model reproduces two primary modes of motion: Brownian and collective, as well as the transition between them. It is demonstrated that hydrodynamic interactions begin to play a significant role when the microswimmer velocity exceeds a critical threshold. At this point, the kinetic energy transferred to the fluid phase is sufficient to generate a noticeable feedback effect on the swimmers' motion. Conversely, a further increase in microswimmers' velocity enhances the role of collisions, causing the system to revert from a collective mode back to a Brownian-like state. A similar transition occurs at higher volume fractions of microswimmers within the colloid. - oai:arXiv.org:2512.08744v1 - cond-mat.soft + Burgers dynamics for Poisson point process initial conditions of the Weibull class + https://arxiv.org/abs/2512.09813 + arXiv:2512.09813v1 Announce Type: cross +Abstract: We derive the statistical properties of one-dimensional Burgers dynamics with stochastic initial conditions for the velocity potential defined by a Poisson point process whose intensity follows a power law with exponent $\alpha > -1$. Working in the inviscid limit and exploiting the geometrical construction of solutions in terms of first-contact parabolas, we derive explicit analytical expressions for a broad set of statistical quantities. These include the one- and two-point probability distributions of the velocity, the multiplicity functions of voids and shocks, and the velocity and density correlation functions together with their associated power spectra. We also show that the full hierarchy of $n$-point distributions factorizes into a sequence of two-point conditional probabilities. This class of initial conditions leads to self-similar evolution and produces probability distributions characterized by stretched-exponential tails, with tail exponents spanning the full range from unity to infinity. The associated characteristic length scale grows as a power law of time, with an exponent lying between zero and one half. + oai:arXiv.org:2512.09813v1 + cond-mat.stat-mech physics.flu-dyn - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - A. Kiverin, S. Luguev, I. Yakovenko + Patrick Valageas - Resource and population dynamics in an agent-environment interaction model - https://arxiv.org/abs/2512.08762 - arXiv:2512.08762v1 Announce Type: cross -Abstract: In any ecosystem, the conditions of the environment and the characteristics of the species that inhabit it are entangled, co-evolving in space and time. We introduce a model that couples active agents with a dynamic environment, interpreted as a nutrient source. Agents are persistent random walkers that gather food from the environment and store it in an inner energy depot. This energy is used for self-propulsion, metabolic expenses, and reproduction. The environment is a two-dimensional surface divided into patches, each of them producing food. Thus, population size and resource distribution become emergent properties of the system. Combining simulations and analytical framework to analyze limiting cases, we show that the system exhibits distinct phases separating quasi-static and highly motile regimes. We observe that, in general, population sizes are inversely proportional to the average energy per agent. Furthermore, we find that, counter-intuitively, reduced access to resources or increased metabolic expenditure can lead to a larger population size. The proposed theoretical framework provides a link between active matter and movement ecology, allowing to investigate short vs long-term strategies to resource exploitation and rationing, as well as sedentary vs wandering strategy. The introduced approach may serve as a tool to describe real-world ecological systems and to test environmental strategies to prevent species extinction. - oai:arXiv.org:2512.08762v1 - q-bio.PE - physics.bio-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Linear and Nonlinear Optical Properties of SiO$_2$/TiO$_2$ Heterostructures Grown by Plasma Enhanced Atomic Layer Deposition + https://arxiv.org/abs/2512.09819 + arXiv:2512.09819v1 Announce Type: cross +Abstract: Second harmonic (SH) radiation can only be generated in non-centrosymmetric bulk crystals under electric dipole approximation. Nonlinear thin films made from bulk crystals are technologically challenging because of complex and high temperature fabrication processes. In this work, heterostructures made of amorphous materials SiO$_2$ and TiO$_2$ were prepared by a CMOS-compatible technique named plasma enhanced atomic layer deposition (PEALD) with deposition temperature at 100 {\deg}C. By using the uniaxial dispersion model, we characterized the form-birefringence property, which can enable the phase matching condition in waveguides or other nonlinear optical applications. By applying a fringe-based technique, we determined the largest diagonal component of the effective second-order bulk susceptibility $\chi_{zzz}^{(2)}$ = 1.30$\pm$0.13 pm/V at a wavelength of 1032 nm. Noteworthy, we observed strong SHG signals from two-component nanolaminates which are several orders of magnitude larger than from single layers. The SHG signals from our samples only require the broken inversion symmetry at the interface. Here optical properties of nanocomposites can be precisely tuned by the promising PEALD technology. + oai:arXiv.org:2512.09819v1 + cond-mat.mtrl-sci + physics.app-ph + Thu, 11 Dec 2025 00:00:00 -0500 cross - http://creativecommons.org/licenses/by-nc-nd/4.0/ - G. Briozzo, G. J. Sibona, F. Peruani + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Jinsong Liu, Martin Mi\v{c}ulka, Raihan Rafi, Sebastian Beer, Denys Sevriukov, Stefan Nolte, Sven Schr\"oder, Andreas T\"unnermann, Isabelle Staude, Adriana Szeghalmi - Commissioning of an experiment for thermodynamic and spectroscopic studies of hydrogen isotopologues at cryogenic conditions - https://arxiv.org/abs/2512.08788 - arXiv:2512.08788v1 Announce Type: cross -Abstract: To study thermodynamic properties and dynamic phase space behavior of hydrogen isotopologues (Q$_2$) at cryogenic temperatures and at high density, the Tritium Absorption InfraRed Spectroscopy 2 (T$_2$ApIR) experiment has been set up and commissioned at Tritium Laboratory Karlsruhe (TLK). In the frame of the experiment, Q$_2$ behavior in different phases, ortho/para states, temperatures (10 K - 300 K) and pressures (up to 2.5 bar a) will be investigated with optical methods, infrared and Raman spectroscopy. The facility consists of a fully tritium compatible cryostat, which includes an optical cell, ortho/para converter and windows for optical and spectroscopic studies. The cryostat can be cooled below the H$_2$ triple point by a two-stage cryocooler and contains openings in the cryogenic shielding for the optical access. The challenge of combining these scientific requirements in a design with high amounts of tritium (14 g), in a limited space, all while maintaining the TLK safety philosophy was solved by the presented design. The experiment is ready to be fully integrated into the TLK closed loop tritium infrastructure. This contribution reports a comprehensive overview of the commissioning phase of the experimental facility and the results of the first commissioning experiments, including cryogenic performance tests, commissioning experiments with non-radioactive gases, and tests of the analytical instruments. - oai:arXiv.org:2512.08788v1 - cond-mat.stat-mech - physics.atm-clus - physics.chem-ph - physics.ins-det - Wed, 10 Dec 2025 00:00:00 -0500 + The Oxygen Valve on Hydrogen Escape Since the Great Oxidation Event + https://arxiv.org/abs/2512.09844 + arXiv:2512.09844v1 Announce Type: cross +Abstract: The Great Oxidation Event (GOE) was a $200$ Myr transition circa 2.4 billion years ago that converted the Earth's anoxic atmosphere to one where molecular oxygen (O$_2$) was abundant (volume mixing ratio $>10^{-4}$). This significant rise in O$_2$ is thought to have substantially throttled hydrogen (H) escape and the associated water (H$_2$O) loss. Atmospheric estimations from the GOE onward place O$_2$ concentrations ranging between 0.1\% to 150\% PAL, where PAL is the present atmospheric level of 21% by volume. In this study we use WACCM6, a three-dimensional Earth System Model to simulate Earth's atmosphere and predict the diffusion-limited escape rate of hydrogen due to varying O$_2$ post-GOE. We find that O$_2$ indirectly acts as a control valve on the amount of hydrogen atoms reaching the homopause in the simulations: less O$_2$ leads to decreased O$_3$ densities, reducing local tropical tropopause temperatures by up to 18 K, which increases H$_2$O freeze-drying and thus reduces the primary source of hydrogen in the considered scenarios. The maximum differences between all simulations in the total H mixing ratio at the homopause and the associated diffusion-limited escape rates are a factor of 3.2 and 4.7, respectively. The prescribed CH$_4$ mixing ratio (0.8 ppmv) sets a minimum diffusion escape rate of $\approx 2 \times 10^{10}$ mol H yr$^{-1}$, effectively a negligible rate when compared to pre-GOE estimates ($\sim 10^{12}-10^{13}$ mol H y$^{-1}$). Because the changes in our predicted escape rates are comparatively minor, our numerical predictions support geological evidence that the majority of Earth's hydrogen escape occurred prior to the GOE. Our work demonstrates that estimations of how the hydrogen escape rate evolved through Earth's history requires 3D chemistry-climate models which include a global treatment of water vapour microphysics. + oai:arXiv.org:2512.09844v1 + astro-ph.EP + physics.geo-ph + Thu, 11 Dec 2025 00:00:00 -0500 cross - http://creativecommons.org/licenses/by-sa/4.0/ - Joshua Kohpei{\ss} (Karlsruhe Institute of Technology), Dominic Batzler (Karlsruhe Institute of Technology), Beate Bornschein (Karlsruhe Institute of Technology), Lutz Bornschein (Karlsruhe Institute of Technology), Robin Gr\"o{\ss}le (Karlsruhe Institute of Technology), Daniel Kurz (Karlsruhe Institute of Technology), Ralph Lietzow (Karlsruhe Institute of Technology), Alexander Marsteller (Karlsruhe Institute of Technology), Michael Sturm (Karlsruhe Institute of Technology), Stefan Welte (Karlsruhe Institute of Technology) + http://creativecommons.org/licenses/by/4.0/ + Gregory J. Cooke, Dan R. Marsh, Catherine Walsh, Felix Sainsbury-Martinez, Marrick Braam - Space-time discretization for barotropic flow stemming from a multisymplectic variational formulation - https://arxiv.org/abs/2512.08841 - arXiv:2512.08841v1 Announce Type: cross -Abstract: This study proposes and analyses a novel higher-order, structure preserving discretization method for inviscid barotropic flows from a Lagrangian perspective. The method is built on a multisymplectic variational principle discretized over a full space-time domain. Flow variables are encoded on a staggered space-time mesh, leveraging the principles of mimetic spectral element discretization. Unlike standard Lagrangian methods, which are prone to mesh distortion, this framework computes fluid deformations in a fixed reference configuration and systematically maps them to the physical domain via the Piola-Kirchhoff stress. Further, the structure preserving design ensures that the discrete analogues of the fundamental conservation laws for mass, momentum, and energy are satisfied up to machine precision. The formulation also inherently handles low-Mach number flows without specialized preconditioning. Numerical experiments on expansion and compression flows confirm the accuracy, stability, and exact conservation properties of the discretization. - oai:arXiv.org:2512.08841v1 - math.NA - cs.NA - physics.flu-dyn - Wed, 10 Dec 2025 00:00:00 -0500 + Programmable Assembly of Ground State Fermionic Tweezer Arrays + https://arxiv.org/abs/2512.09849 + arXiv:2512.09849v1 Announce Type: cross +Abstract: We demonstrate deterministic preparation of arbitrary two-component product states of fermionic $^6$Li atoms in an 8$\times$8 optical tweezer array, achieving motional ground-state fidelities above 98.5\%. Leveraging the large differential magnetic moments for spin-resolution, with parallelized site- and number-resolved control, our approach addresses key challenges for low-entropy quantum state engineering. Combined with high-fidelity spin-, site-, and density-resolved readout within a single \qty{20}{\us} exposure, and \qty{3}{\s} experimental cycles, these advances establish a fast, scalable, and programmable architecture for fermionic quantum simulation. + oai:arXiv.org:2512.09849v1 + cond-mat.quant-gas + physics.atom-ph + quant-ph + Thu, 11 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - Mukthesh Mahadev, Marc Gerritsma + Naman Jain, Jin Zhang, Marcus Culemann, Philipp M. Preiss - A mathematical model of \textit{Culex} population abundance and the impact of vector control interventions in a patchy environment - https://arxiv.org/abs/2512.08842 - arXiv:2512.08842v1 Announce Type: cross -Abstract: Recent mosquito-borne outbreaks have revealed vulnerabilities in our abatement programmes, raising concerns about how abatement-districts should choose optimal future control strategies. Spatial dissemination of vector-borne disease is strongly shaped by the movement of both hosts and mosquitoes, creating substantial overlap between vector activity and pathogen spread. We developed a mathematical model for Culex mosquito dynamics in a patchy landscape, integrating entomological observations, weather-driven factors, and the vector control practices of the Northwest Mosquito Abatement District (NWMAD) in Cook County, Illinois. By coupling a temperature-driven multi-patch ODE model with NWMAD's adulticide and larvicide interventions, we investigated how spatial heterogeneity and control timing influence mosquito abundance. We also evaluated how mosquito dispersal modifies intervention effectiveness by comparing single-patch and two-patch model outcomes. Our results showed that models ignoring spatial connectivity can substantially overestimate the impact of interventions or misidentify the thresholds of vector persistence. Through numerical simulations, we analysed continuous and pulsatile control approaches under varying spatial and temporal configurations. These findings provide insight into optimal strategies for managing Culex populations and mitigating mosquito-borne disease risk in weather-driven, spatially connected environments across Cook County, Illinois. - oai:arXiv.org:2512.08842v1 - q-bio.PE - physics.bio-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Practical and Efficient Verification of Entanglement with Incomplete Measurement Settings + https://arxiv.org/abs/2512.09856 + arXiv:2512.09856v1 Announce Type: cross +Abstract: In this work, we present a practical and efficient framework for verifying entangled states when only a tomographically incomplete measurement setting is available-specifically, when access to observables is severely limited. We show how the experimental estimation of a small number of observables can be directly exploited to construct a large family of entanglement witnesses, enabling the efficient identification of entangled states. Moreover, we introduce an optimization approach, formulated as a semidefinite program, that systematically searches for those witnesses best suited to reveal entanglement under the given measurement constraints. We demonstrate the practicality of the approach in a proof-of-principle experiment with photon-polarization qubits, where entanglement is certified using only a fraction of the full measurement data. These results reveal the maximal usefulness of incomplete measurement settings for entanglement verification in realistic scenarios. + oai:arXiv.org:2512.09856v1 + quant-ph + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 cross - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Suman Bhowmick, Patrick Irwin, Kristina Lopez, Megan Lindsay Fritz, Rebecca Lee Smith + http://creativecommons.org/licenses/by/4.0/ + Jiheon Seong, Jin-Woo Kim, Seungchan Seo, Seung-Hyun Nam, Anindita Bera, Dariusz Chru\'sci\'nski, June-Koo Kevin Rhee, Heonoh Kim, Joonwoo Bae + + + Effective Operators in the Theory of Composites: Hilbert Space Framework + https://arxiv.org/abs/2512.09860 + arXiv:2512.09860v1 Announce Type: cross +Abstract: In this chapter, the Hilbert space framework in the mathematical theory of composite materials is introduced for studying the properties of effective operators. The goal is to introduce some of the key concepts and fundamental theorems in this area while showing that they follow naturally from using only basic results in operator theory on Hilbert spaces. These concepts include the $Z$-problem as an abstraction of a constitutive equation defined in terms of a bounded linear operator on a Hilbert space with a Hodge decomposition, direct and dual $Z$-problems with the duality interpretation of the inverse of an effective operator, and the notion of an $n$-phase composite with orthogonal $Z(n)$-subspace collection. These theorems include sufficient conditions for the existence and uniqueness of both the solution of a $Z$-problem and the effective operator of a $Z$-problem, a representation formula for the effective operator as an operator Schur complement, the Dirichlet and Thomson minimization principles for the effective operator, the result on monotonicity and concavity of the effective operator map, and the Keller-Dykhne-Mendelson duality relations. Moreover, another important theorem given here (which may also be of independent interest to systems theorists) says that an effective operator of an $n$-phase composite with orthogonal $Z(n)$-subspace collection is the Schur complement of a normalized homogeneous semidefinite operator pencil (in particular, has a Bessmertny\u{\i} realization) and, up to a unitary equivalence, the converse is also true. Finally, the general theory presented here is shown to recover classical results dealing with effective conductivity but can also be applied to many other important problems involving composites in physics and engineering, e.g., in elasticity and electromagnetism. + oai:arXiv.org:2512.09860v1 + math-ph + math.FA + math.MP + math.OA + physics.class-ph + Thu, 11 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Aaron Welters - Quantum-Plasmonic Dynamics Modeled via a Modified Langevin Noise Formalism: Numerical Studies of Single-Photon Emission and Two-Photon Interference - https://arxiv.org/abs/2205.03388 - arXiv:2205.03388v2 Announce Type: replace -Abstract: Recent studies have established and rigorously validated a modified Langevin noise formalism that enables first-principles quantization of electromagnetic fields in open and dissipative environments [1,2,3]. Building on this foundation, a fully quantum-mechanical multimode Jaynes-Cummings framework has been developed and verified, providing an accurate description of atom--field interactions in lossy and radiative systems [4]. In this work, we explore the potential of this formalism for nanophotonic applications by modeling representative quantum-plasmonic dynamics. In particular, we present detailed numerical examples for (i) two-photon interference mediated by a quantum plasmonic beam splitter, and (ii) non-Markovian dynamics of an atom located in plasmonic antennas and directional control of out-coupled single-photon fields. These results demonstrate that the proposed modeling approach can be directly used to guide the design and optimization of plasmonic single-photon sources and beam-splitting structures. Moreover, the framework is broadly applicable to the analysis of linear optical components and cavity quantum electrodynamics problems in open and dissipative photonic integrated circuits. - oai:arXiv.org:2205.03388v2 + Atom and spin resolved imaging in a single shot + https://arxiv.org/abs/2512.09865 + arXiv:2512.09865v1 Announce Type: cross +Abstract: We report on an imaging scheme for quantum gases that enables simultaneous detection of two spin states with single-atom resolution. It utilizes the polarization of the emitted photons during fluorescence by choosing appropriate internal states of lithium-6 atoms in a magnetic field. This scheme can readily be implemented to obtain in-situ spin correlations in a wide variety of experimental settings. + oai:arXiv.org:2512.09865v1 + cond-mat.quant-gas physics.optics - quant-ph - Wed, 10 Dec 2025 00:00:00 -0500 - replace + Thu, 11 Dec 2025 00:00:00 -0500 + cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Jisang Seo, Hyunwoo Choi, Thomas E Roth, Jie Zhu, Weng C Chew, Dong-Yeop Na + Tobias Hammel, Maximilian Kaiser, Daniel Dux, Matthias Weidem\"uller, Selim Jochim - Observing network dynamics through sentinel nodes - https://arxiv.org/abs/2408.00045 - arXiv:2408.00045v3 Announce Type: replace -Abstract: A fundamental premise of statistical physics is that the particles in a physical system are interchangeable, and hence the state of each specific component is representative of the system as a whole. This assumption breaks down for complex networks, in which nodes may be extremely diverse, and no single component can truly represent the state of the entire system. It seems, therefore, that to observe the dynamics of social, biological or technological networks, one must extract the dynamic states of a large number of nodes -- a task that is often practically prohibitive. Theoretical tools are also highly restrictive, given the analytically impenetrable combination of complex heterogeneous networks with nonlinear, often hidden, dynamics. To overcome this challenge, we use machine learning techniques to detect the network's sentinel nodes, a set of network components whose combined states can help approximate the average dynamics of the entire network. The method allows us to assess the equilibrium state of a large complex system by tracking just a small number of carefully selected nodes. We find that the sentinels are mainly determined by the network structure such that they can be extracted even with little knowledge of the system's specific interaction dynamics. Therefore, the network's sentinels offer a natural probe by which to observe the system's dynamic states. Intriguingly, sentinels tend to avoid the highly central nodes such as the hubs. - oai:arXiv.org:2408.00045v3 - physics.soc-ph - Wed, 10 Dec 2025 00:00:00 -0500 - replace + Py-DiSMech: A Scalable and Efficient Framework for Discrete Differential Geometry-Based Modeling and Control of Soft Robots + https://arxiv.org/abs/2512.09911 + arXiv:2512.09911v1 Announce Type: cross +Abstract: High-fidelity simulation has become essential to the design and control of soft robots, where large geometric deformations and complex contact interactions challenge conventional modeling tools. Recent advances in the field demand simulation frameworks that combine physical accuracy, computational scalability, and seamless integration with modern control and optimization pipelines. In this work, we present Py-DiSMech, a Python-based, open-source simulation framework for modeling and control of soft robotic structures grounded in the principles of Discrete Differential Geometry (DDG). By discretizing geometric quantities such as curvature and strain directly on meshes, Py-DiSMech captures the nonlinear deformation of rods, shells, and hybrid structures with high fidelity and reduced computational cost. The framework introduces (i) a fully vectorized NumPy implementation achieving order-of-magnitude speed-ups over existing geometry-based simulators; (ii) a penalty-energy-based fully implicit contact model that supports rod-rod, rod-shell, and shell-shell interactions; (iii) a natural-strain-based feedback-control module featuring a proportional-integral (PI) controller for shape regulation and trajectory tracking; and (iv) a modular, object-oriented software design enabling user-defined elastic energies, actuation schemes, and integration with machine-learning libraries. Benchmark comparisons demonstrate that Py-DiSMech substantially outperforms the state-of-the-art simulator Elastica in computational efficiency while maintaining physical accuracy. Together, these features establish Py-DiSMech as a scalable, extensible platform for simulation-driven design, control validation, and sim-to-real research in soft robotics. + oai:arXiv.org:2512.09911v1 + cs.RO + physics.comp-ph + Thu, 11 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by-nc-sa/4.0/ + Radha Lahoti, Ryan Chaiyakul, M. Khalid Jawed + + + Photon emission by vortex particles accelerated in a linac + https://arxiv.org/abs/2512.09921 + arXiv:2512.09921v1 Announce Type: cross +Abstract: We study the photon emission by charged spinless particles with phase vortices and an orbital angular momentum (OAM) projection in longitudinal electric and magnetic fields within the scalar QED. A realistic wave packet of an electron or ion accelerated by a radio-frequency wave locally feels a constant and spatially homogeneous field, which allows us to develop an effective model for losing the angular momentum of the vortex particle due to photon emission. For the fields typical for accelerator facilities, we find that an effective lifetime of the vortex state greatly exceeds the acceleration time. This proves that the acceleration of vortex electrons, ions, muons, and so forth to relativistic energies is possible in conventional linacs, as well as in the wake-field accelerators with higher field gradients, the OAM losses due to the photon emission are mostly negligible, and that the vortex quantum state is highly robust against these losses. + oai:arXiv.org:2512.09921v1 + hep-ph + physics.acc-ph + quant-ph + Thu, 11 Dec 2025 00:00:00 -0500 + cross http://creativecommons.org/licenses/by/4.0/ - 10.1038/s41467-025-64975-x - Neil G. MacLaren, Baruch Barzel, Naoki Masuda + A. Yu. Murtazin, G. K. Sizykh, D. V. Grosman, U. G. Rybak, A. A. Shchepkin, D. V. Karlovets - Surface acoustic waves to monitor active THz metagrating based on VO2 - https://arxiv.org/abs/2412.01210 - arXiv:2412.01210v2 Announce Type: replace -Abstract: We theoretically propose a new approach to in-situ monitor the altered states of pixels in VO2 based active THz amplitude metagrating by using surface acoustic waves (SAWs) generated in LiNbO3 substrate. A single broadband RF response of the SAW device consists of N narrowband frequency channels which code the feedback information on the current pixels states. This way the resistance alteration due to metal-to-insulator transition of all VO2 based pixels of the active THz grating is monitored in advance even without incident radiation. The method provides important new options of monitoring a metasurface aging as well as incorrect switching related to technological defects. Using of the SAW device in all-electrically addressed VO2 based binary grating with tunable period as well as advanced gradient type gratings are modeled. - oai:arXiv.org:2412.01210v2 - physics.optics - physics.app-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Taylor dispersion in variable-density, variable-viscosity pulsatile flows + https://arxiv.org/abs/2503.19623 + arXiv:2503.19623v3 Announce Type: replace +Abstract: The phenomenon of Taylor or shear-induced dispersion of a non-passive scalar field in a pulsatile pipe flow is investigated, accounting for the scalar field's influence on fluid density and transport coefficients. By employing multiple scale analysis, an effective one-dimensional, unsteady mixing problem for the scalar field is obtained, which includes the diffusion coefficient for shear-induced dispersion. The resulting governing equations are applicable to a range of scalar transport problems in pulsatile pipe flows. + oai:arXiv.org:2503.19623v3 + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - G. Y. Karapetyan, M. V. Ochkurov, V. E. Kaydashev + Prabakaran Rajamanickam, Adam D. Weiss - Wave induced fracture of a sea ice analog - https://arxiv.org/abs/2501.04824 - arXiv:2501.04824v2 Announce Type: replace -Abstract: We study at the laboratory scale the rupture of thin floating sheets made of a brittle material under a wave-induced mechanical forcing. We show that the rupture occurs where the curvature is maximum and the break-up threshold strongly depends on the wave properties. We observe that the critical stress for fracture depends on the forcing wavelength. Hence our observations are incompatible with a critical stress criterion for fracture. Instead, our measurements can be rationalized as an energy criterion: a fracture propagates when the material surface energy is lower than the released elastic energy, which depends on the forcing geometry. In light of these findings, it may be worthwhile to revisit current numerical models of sea ice fracture by ocean waves. - oai:arXiv.org:2501.04824v2 + Effects of Geometric Modelling and Blood Rheology in Patient-Specific Arterial Blood Flow Simulations with Speed-Accuracy Trade-Off Analysis + https://arxiv.org/abs/2503.23049 + arXiv:2503.23049v4 Announce Type: replace +Abstract: This study investigates the effects of geometric model reduction on blood flow simulations in the patient-specific descending aorta, followed by speed-accuracy trade-off analysis using 3D simulations. We demonstrate how wall shear stresses (WSS) can be reliably estimated for such realistic arteries using significantly faster simulations of highly idealized equivalent geometries, for any blood rheology model. CFD simulations (3D) are performed at two levels of geometry reduction employing realistic pulsatile inflow and pressure outlet boundary conditions and utilizing both Newtonian and non-Newtonian blood rheology models, including the one developed recently by Apostolidis and Beris. The first level of reduction does not retain effects due to local asymmetry but can approximate various flow parameters and patterns, while showing a significant computational speedup. However, further simplification to an idealized smooth geometry loses all information about the vortex structures and flow circulation. The non-Newtonian models retain more accuracy than the Newtonian models in geometry reductions, as quantified by correlations defined in this study. The idealized smooth geometry, combined with area correction, yields WSS estimates that closely approximate those of the actual artery. This study is expected to be applicable in geometric reductions (and speed enhancements) for more complex patient-specific 3D simulations while maintaining accuracy. + oai:arXiv.org:2503.23049v4 physics.flu-dyn - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - Baptiste Auvity, Laurent Duchemin, Antonin Eddi, St\'ephane Perrard + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + 10.1016/j.jnnfm.2025.105534 + Rishi Kumar, K. Muralidhar, Indranil Saha Dalal - Residual-based Chebyshev filtered subspace iteration for sparse Hermitian eigenvalue problems tolerant to inexact matrix-vector products - https://arxiv.org/abs/2503.22652 - arXiv:2503.22652v4 Announce Type: replace -Abstract: Chebyshev Filtered Subspace Iteration (ChFSI) has emerged as a robust alternative to Krylov eigensolvers for extracting a small subset of extremal eigenpairs from large sparse matrices, particularly in situations where these eigenpairs must be computed repeatedly as the system matrix evolves within an outer iteration. In this work, we propose R-ChFSI, a residual based reformulation of ChFSI designed to exhibit strong convergence properties even when the matrix-vector products are computed inexactly. We derive convergence guarantees under matrix-vector product approximations, providing a rigorous foundation for the method in large-scale eigenvalue computations. The tolerance of R-ChFSI to inexact matrix-vector products enables an efficient treatment of generalized Hermitian definite eigenproblems of the form $\textbf{A} \textbf{x} = \lambda \textbf{B} \textbf{x}$ where exact factorizations or high-accuracy iterative solves for evaluating $\textbf{B}^{-1}$ are often prohibitively expensive. Moreover, R-ChFSI naturally accommodates low-precision arithmetic for both standard and generalized eigenproblems, making it well-suited for modern hardware accelerators optimised for mixed-precision computation. To demonstrate the effectiveness of the approach, extensive numerical experiments are conducted on finite-element discretized eigenproblems with millions of degrees of freedom, solving for thousands of eigenpairs arising in \emph{ab initio} material modelling using Kohn-Sham density functional theory. For generalized eigenproblems employing approximate $\textbf{B}^{-1}$, R-ChFSI achieves desired residual norms orders of magnitude smaller than those obtained with standard ChFSI. In addition, R-ChFSI reliably reaches target residual tolerances (e.g., 10$^{-8}$) even with FP32 and TF32 arithmetic, significantly outperforming standard ChFSI in similar settings. - oai:arXiv.org:2503.22652v4 - physics.comp-ph - cs.NA - math.NA - Wed, 10 Dec 2025 00:00:00 -0500 + AC-LGADs Fermilab Front-End Electronics Characterization + https://arxiv.org/abs/2504.08932 + arXiv:2504.08932v4 Announce Type: replace +Abstract: We characterized the front-end electronics used to process high-frequency signals from low-gain avalanche diodes (LGADs) at the Fermilab Test Beam Facility. LGADs are silicon detectors employed for charged particle tracking, offering exceptional spatial and temporal resolution. The purpose of this characterization was to understand how the time resolution is influenced by the front-end electronics. To achieve this, we developed a setup capable of generating input signals with varying amplitudes. The output results demonstrated that signal processing by the front-end electronics plays a crucial role in enhancing time resolution. We showed that the time resolution achieved by the FEE board is better than $2\: ps$ at the $1\sigma$ level. + oai:arXiv.org:2504.08932v4 + physics.ins-det + hep-ex + Thu, 11 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/publicdomain/zero/1.0/ - Nikhil Kodali, Kartick Ramakrishnan, Phani Motamarri + http://creativecommons.org/licenses/by/4.0/ + 10.1016/j.nima.2025.171081 + Ren\'e R\'ios, Esteban Felipe Molina Cardenas, Cristian Pe\~na, Orlando Soto, William Brooks, Artur Apresyan, Sergey Los, Claudio San Mart\'in - Modelling Lateral Spread in Wire Flat Rolling - https://arxiv.org/abs/2504.06300 - arXiv:2504.06300v2 Announce Type: replace -Abstract: A mathematical model for wire rolling is developed, focusing on predicting the lateral spread. This provides, for the first time, an analytic model of lateral spread without any fitting parameters. The model is derived directly from the governing equations, assuming a rigid, perfectly plastic material and exploiting the thinness of the wire (in thickness and width) relative to the roller size. Results are compared against experiments performed on stainless steel wire using 100mm diameter rolls, demonstrating accurate predictions of lateral spread across a wide range of wire diameters (2.96mm-7.96mm) and reduction ratios (20%-60%), all without the need for fitting parameters. Since the model requires only seconds to compute, the model's valid range is explored for varying roll diameter, wire diameter, and reduction ratio, and their effects on the resulting lateral spread characterized. The model can serve as a robust tool for validating FE results, guiding process design, and laying the foundation for future improved models. Matlab code to evaluate the model is provided in the supplementary material. - oai:arXiv.org:2504.06300v2 - physics.class-ph - cond-mat.mtrl-sci - Wed, 10 Dec 2025 00:00:00 -0500 + Knowledge Independence Breeds Disruption but Limits Recognition + https://arxiv.org/abs/2504.09589 + arXiv:2504.09589v2 Announce Type: replace +Abstract: Despite extensive research on scientific disruption, two questions remain: why disruption has declined amid growing knowledge, and why disruptive work receives fewer and delayed citations. One way to address these questions is to identify an intrinsic, paper-level property that reliably predicts disruption and explains both patterns. Here, we propose a novel measure, knowledge independence, capturing the extent to which a paper draws on references that do not cite one another. Analyzing 114 million publications, we find that knowledge independence strongly predicts disruption and mediates the disruptive advantage of small, onsite, and fresh teams. Its long-term decline, nonreproducible by null models, provides a mechanistic explanation for the parallel decline in disruption. Causal and simulation evidence further indicates that knowledge independence drives the persistent trade-off between disruption and impact. Taken together, these findings fill a critical gap in understanding scientific innovation, revealing a universal law: Knowledge independence breeds disruption but limits recognition. + oai:arXiv.org:2504.09589v2 + physics.soc-ph + cs.DL + cs.SI + Thu, 11 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - Mozhdeh Erfanian, Carl D. Slater, Edward James Brambley + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Xiaoyao Yu, Talal Rahwan, Tao Jia - Climate impacts of forced equatorial superrotation in an idealized GCM - https://arxiv.org/abs/2504.06909 - arXiv:2504.06909v3 Announce Type: replace -Abstract: While it is expected that the large-scale tropical circulation should undergo some changes in a warmer climate, it remains an open question whether its characteristic features, such as the Hadley cell, the intertropical convergence zone, or the weak surface easterlies, could take a completely different shape. As an example, it has been hypothesized that the Earth's atmosphere may have experienced equatorial superrotation -- i.e. westerly winds at the equator -- during its history. The possibility of equatorial superrotation has been studied in a range of planetary atmospheres, including Earth-like ones, with the objective of understanding the underlying dynamical processes. However, the broader impact that this dramatic circulation change would have on the climate system is practically unexplored. This is the question we address here. We perform idealized GCM simulations with an imposed equatorial torque to investigate how a forced superrotating atmosphere affects surface temperature and the water cycle. We show that these effects are quite large and directly related to the global circulation changes, which extend beyond the tropical atmosphere. Using tools including a forcing/feedback analysis and a moist energy balance model, we argue that the dominant mechanism is changes in atmospheric energy transport, driven in particular by the collapse of the meridional overturning circulation, and to a smaller extent by the appearance of an equatorial jet, and the concomitant redistribution of moisture in the tropics, leading to a much weaker relative humidity gradient which has strong radiative effects. - oai:arXiv.org:2504.06909v3 - physics.ao-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Quasi-monoenergetic Deuteron Acceleration via Boosted Coulomb Explosion by Reflected Picosecond Laser Pulse + https://arxiv.org/abs/2504.19789 + arXiv:2504.19789v3 Announce Type: replace +Abstract: Generation of quasi-monoenergetic ions by intense laser is one of long-standing goals in laser-plasma physics. However, existing laser-driven ion acceleration schemes often produce broad energy spectra and limited control over ion species. Here we propose the acceleration mechanism, boosted Coulomb explosion, initiated by a standing wave, which is formed in a pre-expanded plasma by the interference between a continuously incoming main laser pulse and the pulse reflected by a solid target, where the pre-expanded plasma is formed from a thin layer on the solid target by a relatively strong pre-pulse. This mechanism produces a persistent Coulomb field on the target front side with field strengths on the order of TV/m for picoseconds. We experimentally demonstrate generation of quasi-monoenergetic deuterons up to 50 MeV using an in-situ D$_2$O-deposited target. Our results show that the peak energy can be tuned by the laser pulse duration. + oai:arXiv.org:2504.19789v3 + physics.plasm-ph + hep-ex + Thu, 11 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Tim Marino, Michael P. Byrne, Corentin Herbert + Tianyun Wei, Zechen Lan, Yasunobu Arikawa, Yanjun Gu, Takehito Hayakawa, Alessio Morace, Ryuya Yamada, Kohei Yamanoi, Koichi Honda, Masaki Kando, Nakanii Nobuhiko, Seyed Reza Mirfayzi, Sergei V. Bulanov, Akifumi Yogo - Identifying the approach of a major earthquake - https://arxiv.org/abs/2504.19431 - arXiv:2504.19431v4 Announce Type: replace -Abstract: By analyzing the seismicity in natural time and studying the evolution of the fluctuations of the entropy change of seismicity under time reversal for various scales of different length i (number of events), we can identify the approach of a major earthquake (EQ) occurrence. The current investigation is extended from 1984 until 2025 for the seismicity in Japan. - oai:arXiv.org:2504.19431v4 - physics.geo-ph - Wed, 10 Dec 2025 00:00:00 -0500 + The NEXT-100 Detector + https://arxiv.org/abs/2505.17848 + arXiv:2505.17848v2 Announce Type: replace +Abstract: The NEXT collaboration is dedicated to the study of double beta decays of $^{136}$Xe using a high-pressure gas electroluminescent time projection chamber. This advanced technology combines exceptional energy resolution ($\leq 1\%$ FWHM at the $Q_{\beta\beta}$ value of the neutrinoless double beta decay) and powerful topological event discrimination. Building on the achievements of the NEXT-White detector, the NEXT-100 detector started taking data at the Laboratorio Subterr\'aneo de Canfranc (LSC) in May of 2024. Designed to operate with xenon gas at 13.5 bar, NEXT-100 consists of a time projection chamber where the energy and the spatial pattern of the ionising particles in the detector are precisely retrieved using two sensor planes (one with photo-multiplier tubes and the other with silicon photo-multipliers). The detector has been operating at stable conditions using argon and xenon gases at $\sim$4 bar and drift fields of 74 V/cm and 118 V/cm, respectively. Alpha decays from the $^{222}$Rn chain have been used to test and monitor the stability of the detector, showing a constant electron lifetime in the drift volume. In this paper, in addition to reporting the results of the commissioning run, we provide a detailed description of the NEXT-100 detector, describe its assembly, and present the current estimation of the radiopurity budget. + oai:arXiv.org:2505.17848v2 + physics.ins-det + nucl-ex + Thu, 11 Dec 2025 00:00:00 -0500 + replace + http://creativecommons.org/licenses/by/4.0/ + NEXT Collaboration, C. Adams, H. Almaz\'an, V. \'Alvarez, A. I. Aranburu, L. Arazi, I. J. Arnquist, F. Auria-Luna, S. Ayet, Y. Ayyad, C. D. R. Azevedo, K. Bailey, F. Ballester, J. E. Barcelon, M. del Barrio-Torregrosa, A. Bayo, J. M. Benlloch-Rodr\'iguez, F. I. G. M. Borges, A. Brodoline, N. Byrnes, A. Castillo, E. Church, L. Cid, M. Cid, X. Cid, C. A. N. Conde, C. Cortes-Parra, F. P. Coss\'io, R. Coupe, E. Dey, P. Dietz, C. Echeverria, M. Elorza, R. Esteve, R. Felkai, L. M. P. Fernandes, P. Ferrario, F. W. Foss, Z. Freixa, J. Garc\'ia-Barrena, J. J. G\'omez-Cadenas, J. W. R. Grocott, R. Guenette, J. Hauptman, C. A. O. Henriques, J. A. Hernando Morata, P. Herrero-G\'omez, V. Herrero, C. Herv\'es Carrete, Y. Ifergan, A. F. B. Isabel, B. J. P. Jones, F. Kellerer, L. Larizgoitia, A. Larumbe, P. Lebrun, F. Lopez, N. L\'opez-March, R. Madigan, R. D. P. Mano, A. Marauri, A. P. Marques, J. Mart\'in-Albo, A. Mart\'inez, G. Mart\'inez-Lema, M. Mart\'inez-Vara, R. L. Miller, K. Mistry, J. Molina-Canteras, F. Monrabal, C. M. B. Monteiro, F. J. Mora, K. E. Navarro, P. Novella, D. R. Nygren, E. Oblak, I. Osborne, J. Palacio, B. Palmeiro, A. Para, I. Parmaksiz, A. Pazos, J. Pelegrin, M. P\'erez Maneiro, M. Querol, J. Renner, I. Rivilla, C. Rogero, L. Rogers, B. Romeo, C. Romo-Luque, E. Ruiz-Ch\'oliz, P. Saharia, F. P. Santos, J. M. F. dos Santos, M. Seemann, I. Shomroni, A. L. M. Silva, P. A. O. C. Silva, A. Sim\'on, S. R. Soleti, M. Sorel, J. Soto-Oton, J. M. R. Teixeira, S. Teruel-Pardo, J. F. Toledo, C. Tonnel\'e, S. Torelli, J. Torrent, A. Trettin, P. R. G. Valle, M. Vanga, P. V\'azquez Cabaleiro, J. F. C. A. Veloso, J. D. Villamil, J. Waiton, A. Yubero-Navarro + + + Modified Marrone-Treanor model: parameterization and benchmarking for five-species air + https://arxiv.org/abs/2506.20521 + arXiv:2506.20521v2 Announce Type: replace +Abstract: We present updated parameters for five-species air (N2, O2, NO, N and O) reactions to be used with the Modified Marrone-Treanor two-temperature model. The vibrational relaxation and chemical reaction rates are derived from quasiclassical trajectory calculations and direct molecular simulations using ab initio potential energy surfaces. The resulting model enables efficient computational fluid dynamics simulations of nonequilibrium air chemistry in hypersonic flows. We show that the model reproduces direct molecular simulation benchmark solutions with high accuracy in zero-dimensional heat baths representative of strong nonequilibrium post-shock conditions. The model's analytical expressions for dissociation rate coefficient and vibrational energy change per reaction ensure that the correct amount of energy is transferred between the vibrational and trans-rotational modes. Detailed balance is imposed for three-body recombination reactions and our simulations exhibit quasi-steady-state dissociation rates and proper approach to thermochemical equilibrium. In direct comparison with the Park TTv model, the Modified Marrone-Treanor model predicts significantly slower conversion of N2 into N below 10000 K and significantly more NO production at all temperatures. This is likely due to its significantly higher Zeldovich reaction rates compared to Park. + oai:arXiv.org:2506.20521v2 + physics.chem-ph + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Panayiotis A. Varotsos, Nicholas V. Sarlis, Toshiyasu Nagao + Erik Torres, Thomas Gross, Graham V. Candler, Thomas E. Schwartzentruber - Surface Waves and Axoplasmic Pressure Waves in Action Potential Propagation: Fundamentally Different Physics or Two Sides of the Same Coin? - https://arxiv.org/abs/2505.24580 - arXiv:2505.24580v2 Announce Type: replace -Abstract: In this commentary, we argue that El Hady and Machta's "surface wave" model for mechanical waves accompanying action potential (AP) propagation describes the same underlying process as the "axoplasmic pressure wave" model introduced earlier by Rvachev. Both models describe mechanical modes that store potential energy in the elastic components of the axon (axonal membrane, cytoskeleton, bulk axoplasmic deformation), with kinetic energy carried by the axoplasmic fluid and axoplasmic viscosity playing a significant role. The "surface wave" model quantitatively considers driving by the traveling electrical depolarization wave of the AP, whereas the "axoplasmic pressure wave" model qualitatively considers driving not only by the AP's electrical depolarization but also by other mechanisms, such as cytoskeletal actomyosin contractility. In addition, the "axoplasmic pressure wave" model considers mechanisms for synchronizing the depolarization wave and the pressure wave. Although derived using different approaches, the two models yield identical dependencies for the mechanical modes in key limits. The confusion in the literature, which treats these models as describing distinct processes, needs to be resolved to improve comprehensive understanding of the AP phenomenon and to guide future research. - oai:arXiv.org:2505.24580v2 - physics.bio-ph - q-bio.NC - Wed, 10 Dec 2025 00:00:00 -0500 + On how walls shape dissipation intermittency + https://arxiv.org/abs/2506.22917 + arXiv:2506.22917v2 Announce Type: replace +Abstract: Intermittency of energy dissipation has long been studied via high-order moments in homogeneous and isotropic turbulence, but not much where the boundary effects are explicitly included. Here, we derive two fundamental Reynolds number scaling expressions for dissipation moments in wall-bounded flows -- one in the outer region where the boundary effects are weak and the other close to the walls where those effects are strong -- and support these expressions by direct numerical simulations. Dissipation moments in the outer region follow universal power laws with exponents linked to anomalous scaling of velocity structure functions. In contrast, moments near the wall follow a bounded defect law, leading to a finite asymptotic limit without intermittency. For very large Reynolds numbers, the outer proposal predicts vanishing dissipation compared to that on the wall, highlighting the need for solid boundaries in generating Onsager-type singularities. + oai:arXiv.org:2506.22917v2 + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by-nc-nd/4.0/ - 10.1142/S1793048025500055 - Marat M. Rvachev, Benjamin Drukarch + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Peng-Yu Duan, Xi Chen, Katepalli R. Sreenivasan - Stochastic modeling of deterministic laser chaos using generator extended dynamic mode decomposition - https://arxiv.org/abs/2506.05798 - arXiv:2506.05798v3 Announce Type: replace -Abstract: Recently, chaotic phenomena in laser dynamics have attracted much attention to its applied aspects, and a synchronization phenomenon, leader-laggard relationship, in time-delay coupled lasers has been used in reinforcement learning. In the present paper, we discuss the possibility of capturing the essential stochasticity of the leader-laggard relationship; in nonlinear science, it is known that coarse-graining allows one to derive stochastic models from deterministic systems. We derive stochastic models with the aid of the Koopman operator approach, and we clarify that the low-pass filtered data is enough to recover the essential features of the original deterministic chaos, such as peak shifts in the distribution of being the leader and a power-law behavior in the distribution of switching-time intervals. We also confirm that the derived stochastic model works well in reinforcement learning tasks, i.e., multi-armed bandit problems, as with the original laser chaos system. - oai:arXiv.org:2506.05798v3 - physics.app-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Low-Energy Calibration of SuperCDMS HVeV Cryogenic Silicon Calorimeters Using Compton Steps + https://arxiv.org/abs/2508.02402 + arXiv:2508.02402v2 Announce Type: replace +Abstract: Cryogenic calorimeters for low-mass dark matter searches have achieved sub-eV energy resolutions, driving advances in both low-energy calibration techniques and our understanding of detector physics. The energy deposition spectrum of gamma rays scattering off target materials exhibits step-like features, known as Compton steps, near the binding energies of atomic electrons. We demonstrate a successful use of Compton steps for sub-keV calibration of cryogenic silicon calorimeters, utilizing four SuperCDMS High-Voltage eV-resolution (HVeV) detectors operated with 0 V bias across the crystal. This new calibration at 0 V is compared with the established high-voltage calibration using optical photons. The comparison indicates that the detector response at 0 V is about 30% weaker than expected, highlighting challenges in detector response modeling for low-mass dark matter searches. + oai:arXiv.org:2508.02402v2 + physics.ins-det + astro-ph.IM + hep-ex + Thu, 11 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Kakutaro Fukushi, Jun Ohkubo + 10.1103/jj7w-gkgg + Phys.Rev.D 112 (2025) 092014 + SuperCDMS Collaboration, M. F. Albakry, I. Alkhatib, D. Alonso-Gon\'zalez, D. W. P. Amaral, J. Anczarski, T. Aralis, T. Aramaki, I. Ataee Langroudy, C. Bathurst, R. Bhattacharyya, A. J. Biffl, P. L. Brink, M. Buchanan, R. Bunker, B. Cabrera, R. Calkins, R. A. Cameron, C. Cartaro, D. G. Cerde\~no, Y. -Y. Chang, M. Chaudhuri, J. -H. Chen, R. Chen, N. Chott, J. Cooley, H. Coombes, P. Cushman, R. Cyna, S. Das, S. Dharani, M. L. di Vacri, M. D. Diamond, M. Elwan, S. Fallows, E. Fascione, E. Figueroa-Feliciano, S. L. Franzen, A. Gevorgian, M. Ghaith, G. Godden, J. Golatkar, S. R. Golwala, R. Gualtieri, J. Hall, S. A. S. Harms, C. Hays, B. A. Hines, Z. Hong, L. Hsu, M. E. Huber, V. Iyer, V. K. S. Kashyap, S. T. D. Keller, M. H. Kelsey, K. T. Kennard, Z. Kromer, A. Kubik, N. A. Kurinsky, M. Lee, J. Leyva, B. Lichtenberg, J. Liu, Y. Liu, E. Lopez Asamar, P. Lukens, R. L\'opez No\'e, D. B. MacFarlane, R. Mahapatra, J. S. Mammo, N. Mast, A. J. Mayer, P. C. McNamara, H. Meyer zu Theenhausen, \'E. Michaud, E. Michielin, K. Mickelson, N. Mirabolfathi, M. Mirzakhani, B. Mohanty, D. Mondal, D. Monteiro, J. Nelson, H. Neog, V. Novati, J. L. Orrell, M. D. Osborne, S. M. Oser, L. Pandey, S. Pandey, R. Partridge, P. K. Patel, D. S. Pedreros, W. Peng, W. L. Perry, R. Podviianiuk, M. Potts, S. S. Poudel, A. Pradeep, M. Pyle, W. Rau, E. Reid, R. Ren, T. Reynolds, M. Rios, A. Roberts, A. E. Robinson, L. Rosado Del Rio, J. L. Ryan, T. Saab, D. Sadek, B. Sadoulet, S. P. Sahoo, I. Saikia, S. Salehi, J. Sander, B. Sandoval, A. Sattari, B. Schmidt, R. W. Schnee, B. Serfass, A. E. Sharbaugh, R. S. Shenoy, A. Simchony, P. Sinervo, Z. J. Smith, R. Soni, K. Stifter, J. Street, M. Stukel, H. Sun, E. Tanner, N. Tenpas, D. Toback, A. N. Villano, J. Viol, B. von Krosigk, Y. Wang, O. Wen, Z. Williams, M. J. Wilson, J. Winchell, S. Yellin, B. A. Young, B. Zatschler, S. Zatschler, A. Zaytsev, E. Zhang, L. Zheng, A. Zuniga, M. J. Zurowski - Inference of a time delay in stochastic systems - https://arxiv.org/abs/2507.10429 - arXiv:2507.10429v2 Announce Type: replace -Abstract: Time delay is ubiquitous in many experimental and real-world situations. It is often unclear whether time delay plays a significant role in observed phenomena, and if it does, how long the time lag really is. This would be invaluable knowledge when analyzing and modeling such systems. Hitherto, no universal method is available by which the time delay can be inferred. To address this problem, we propose and demonstrate two different methods to infer time delay in overdamped Langevin systems with delayed feedback. In the first part, we focus on the power spectral density based on the positional data and use a characteristic signature of the time delay to infer the delay time. In limiting cases, we establish a direct relation of the observations made for nonlinear time-delayed feedback forces to analytical results obtained for the linear system. In other situations despite the absence of this direct relation, the characteristic signature remains and can be exploited by a semiautomatic method to infer the delay time. Furthermore, it may not always desirable or possible to observe a system for a long time to infer dependencies and parameters. Thus, in the second part, we propose for the first time a probing method combined with a neural network to infer the delay time, which requires only short observation time series. These proposed methods for inferring time delays in stochastic systems may prove to be valuable tools for gaining deeper insight into the role of delay across a wide range of applications -- from the behavior of individual colloidal particles under feedback control to emergent collective phenomena such as flocking and swarming. - oai:arXiv.org:2507.10429v2 - physics.data-an - cond-mat.soft - cond-mat.stat-mech - Wed, 10 Dec 2025 00:00:00 -0500 + Nitrogen-Vacancy Emission from Nanodiamond: Size, Depth, and Surroundings + https://arxiv.org/abs/2508.08565 + arXiv:2508.08565v3 Announce Type: replace +Abstract: The negatively charged nitrogen-vacancy (NV) center in diamond is a leading solid-state quantum emitter, offering spin-photon interfaces over a wide temperature range with applications from electromagnetic sensing to bioimaging. While NV centers in bulk diamond are well understood, embedding them in nanodiamond (ND) introduces complexities from size, NV location, and NV polarizations. NVs in ND show altered fluorescence properties including longer lifetimes, lower quantum efficiency, and higher sensitivity to dielectric surroundings, which arise from radiative suppression, surface-induced non-radiative decay, and escape inefficiency at the diamond-background interface. Prior models typically addressed isolated aspects, such as dielectric contrast or surface quenching, without integrating full quantum-optical NV behavior with classical electrodynamics. We present a hybrid framework coupling rigorous electromagnetic simulations with a quantum-optical NV model including phonon sideband dynamics. NV emission is found to depend strongly on ND size, NV position, and surrounding refractive index. Our results explain observations such as shallow NVs in water-coated ND appearing brighter than deeper ones in air. This integrated model provides a unified framework for realistic NV in ND emission scenarios and informs the design of efficient NV-based sensors and quantum devices, advancing understanding of quantum emitter photophysics in nanoscale crystals. + oai:arXiv.org:2508.08565v3 + physics.optics + cond-mat.mes-hall + quant-ph + Thu, 11 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1103/7hsc-mmzc - Robin A. Kopp, Sabine H. L. Klapp, Deepak Gupta - - - Three-dimensional numerical study on hydrogen bubble growth at electrode - https://arxiv.org/abs/2507.15582 - arXiv:2507.15582v3 Announce Type: replace -Abstract: Three-dimensional direct numerical simulation of electrolysis is applied to investigate the growth and detachment of bubbles at electrodes. - The moving gas-liquid interface is modeled employing the VOF-based method. To ensure the accuracy of the simulations, - a mesh-independence study has been performed. - The simulations include the growth phase of the bubbles, followed by their detachment from the electrode surface - and the results are validated with analytical models and experimental data. - The bubble growth is diffusion-controlled, leading to the scaling \(R = 2\beta t^{1/2}\), but our simulation overpredicts the growth exponent during the initial stage. - We further demonstrate that the number of nucleation sites significantly affects gas transport, as quantified by the Sherwood number. - The influences of contact angle and nucleation site on bubble detachment are also examined. - The predicted detachment radius varies linearly with contact angle, consistent with the well-known relation - \( R_{det}=0.6 \theta \sqrt{\sigma/(\rho_c-\rho_d)g}\) between the volume-equivalent radius and contact angle, confirming that the surface tension is the dominant attachment force. - Finally, as the nucleation sites increase, the induced bubble coalescence accelerates the bubble detachment. Taken together, - these findings give us valuable insights into improving gas bubble removal and enhancing overall electrolysis efficiency. - oai:arXiv.org:2507.15582v3 - physics.flu-dyn - Wed, 10 Dec 2025 00:00:00 -0500 + 10.1002/andp.202500367 + Annalen der Physik,2025;0:e00367 + Harini Hapuarachchi, Francesco Campaioli, Jared H Cole, Andrew D Greentree, Qiang Sun + + + A comparative study of data- and image- domain LSRTM under velocity-impedance parametrization + https://arxiv.org/abs/2508.10405 + arXiv:2508.10405v2 Announce Type: replace +Abstract: Least-squares reverse time migration (LSRTM) is one of the classic seismic imaging methods to reconstruct model perturbations within a known reference medium. It can be computed in either data or image domain using different methods by solving a linear inverse problem, whereas a careful comparison analysis of them is lacking in the literature. In this article, we present a comparative study for multiparameter LSRTM in data- and image- domain in the framework of SMIwiz open software. Different from conventional LSRTM for recovering only velocity perturbation with variable density, we focus on simultaneous reconstruction of velocity and impedance perturbations after logorithmic scaling, using the first-order velocity-pressure formulation of acoustic wave equation. The first 3D data-domain LSRTM example has been performed to validate our implementation, involving expensive repetition of Born modelling and migration over a number of iterations. As a more cost-effective alternative, the image-domain LSRTM is implemented using point spread function (PSF) and nonstationary deblurring filter. Dramatic disctinctions between data and image domain methods are discovered with 2D Marmousi test: (1) The data-domain multiparameter inversion provides much better reconstruction of reflectivity images than image-domain approaches, thanks to the complete use of Hessian in Krylov space; (2) The poor multiparameter image-domain inversion highlights the limitation of incomplete Hessian sampling and strong parameter crosstalks, making it difficult to work in practice; (3) In contrast, monoparameter image-domain inversion for seismic impedance is found to work well. These observations have been further validated on Viking Graben Line 12 dataset. + oai:arXiv.org:2508.10405v2 + physics.geo-ph + math-ph + math.MP + Thu, 11 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by-sa/4.0/ - Wei Qin, Tian Long, Jacob Maarek, St\'ephane Zaleski + http://creativecommons.org/licenses/by/4.0/ + Pengliang Yang, Zhengyu Ji - Waves in a shear flow: transition between the KH, Holmboe and Miles instability - https://arxiv.org/abs/2507.20166 - arXiv:2507.20166v2 Announce Type: replace -Abstract: We investigate shear driven wave generation at the interface between two immiscible fluids, using an exponential velocity profile with a sharp density interface representing stable stratification. At low Froude and high Bond numbers, conditions relevant to geophysical and astrophysical flows, we identify a novel transition in the fastest growing mode: from Kelvin Helmholtz (KH) instability at high density ratio (delta = 0.9), to Holmboe (H) instability as delta approaches 0.5, and ultimately to the Miles (1957) critical layer instability as delta approaches 0.001, representative of the air water system. Remarkably, the Miles mode, characterized by a sharp jump in inviscid Reynolds stress (tau) at the critical layer, persists up to delta = 0.01, i.e., ten times the air water value. As delta increases, the vertical variation of tau undergoes a qualitative change, from a sharp jump at the critical layer for delta much less than 1 to a smooth transition through it for delta greater than or equal to 0.5. A theoretical explanation is provided. In the moderate to high density ratio regime, comparison with a piecewise-linear (PL) velocity profile confirms the presence of both H and KH instabilities in the exponential profile. Nonlinear simulations of the incompressible Euler equations with gravity and surface tension show excellent agreement with linear theory for delta = 0.01 up to five wave periods. At delta = 0.1, waves saturate into finite-amplitude structures with capillary ripples, while at delta = 0.5, the waves develop sheared cusps and emit spume, resembling asymmetric Holmboe waves observed experimentally. At delta = 0.9, the waves rapidly evolve into classic KH spirals. Comparisons with the PL profile highlight the role of background curvature and the critical layer. This work presents, for the first time, all three canonical instabilities within a single background state. - oai:arXiv.org:2507.20166v2 + Asymptotic limits of the axisymmetric solution of the Brinkman equation for a point force near a no-slip wall + https://arxiv.org/abs/2509.08678 + arXiv:2509.08678v2 Announce Type: replace +Abstract: We derive the far-field and near-field solutions for the Green's function of a point force acting perpendicular to a no-slip wall in a Brinkman fluid, focusing on the regime where the distance between the force and the wall is much smaller than the screening length. The general solution is obtained in closed form up to a single integral and can be systematically expanded in a Taylor series in both the far-field and near-field limits. The flow can then be expressed as a series of source-multipole singularities with an additional, analytically known, correction in the proximity of the wall. Comparisons with numerical integration demonstrate the accuracy and reliability of the asymptotic expansions. The results are also applicable to the unsteady Stokes flow driven by a localized assembly of forces, such as a beating cilium protruding from a flat surface. + oai:arXiv.org:2509.08678v2 physics.flu-dyn - Wed, 10 Dec 2025 00:00:00 -0500 + cond-mat.soft + Thu, 11 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Anil Kumar, S. Ravichandran, Ratul Dasgupta + Abdallah Daddi-Moussa-Ider, Andrej Vilfan - In-vivo 6D heart motion analysis for emerging self-powered cardiac implants - https://arxiv.org/abs/2507.21263 - arXiv:2507.21263v2 Announce Type: replace -Abstract: Self-powered intracardiac implant devices show great promise for future clinical applications due to their extended operational lifespan and the potential to reduce the need for high-risk repeat surgeries. This study investigates the feasibility of harvesting energy from cardiac motion through in vivo testing of intracardiac devices. Comprehensive three-dimensional translational and rotational cardiac motions are captured in a porcine model using a miniaturized 9-degree-of-freedom motion sensor implanted at six strategic epicardial sites. Kinematic criteria are developed to evaluate the energy harvesting potential of each implant site based on the available kinetic energy, acceleration, and jerk factors. The recorded heart motion signals are analyzed and applied to a conceptual energy harvester proposed to identify the optimal implant site. The results reveal that the left ventricular apex emerges as a preferable site for energy harvesting, particularly at moderate heart rates. These findings offer valuable insights into optimizing self-powered intracardiac implants, reducing dependency on battery replacements, and enhancing long-term patient safety. - oai:arXiv.org:2507.21263v2 - physics.med-ph - Wed, 10 Dec 2025 00:00:00 -0500 + An accurate mean-field equation for voter model dynamics on scale-free networks + https://arxiv.org/abs/2509.13485 + arXiv:2509.13485v2 Announce Type: replace +Abstract: Understanding the emergent macroscopic behavior of dynamical systems on networks is a crucial but challenging task.One of the simplest and most effective methods to construct a reduced macroscopic model is given by mean-field theory. The resulting approximations perform well on dense and homogeneous networks but poorly on scale-free networks, which, however, are more realistic in many applications. In this paper, we introduce a modified version of the mean-field approximation for voter model dynamics on scale-free networks. The two main deviations from classical theory are that we use degree-weighted shares as coarse variables and that we introduce a correlation factor that can be interpreted as slowing down dynamics induced by interactions. We observe that the correlation factor is only a property of the network and not of the state or of parameters of the process. This approach achieves a significantly smaller approximation error than standard methods without increasing dimensionality. + oai:arXiv.org:2509.13485v2 + physics.soc-ph + Thu, 11 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by-nc-nd/4.0/ - Milad Hasani, John Huber, Benedict Kjaergaard, Tomas Zaremba, Alireza Rezania, Sam Riahi + Marvin L\"ucke, Stefanie Winkelmann, P\'eter Koltai - Unsteady aerodynamic theory and experiments of hovering membrane wings - https://arxiv.org/abs/2509.00666 - arXiv:2509.00666v2 Announce Type: replace -Abstract: We investigate the unsteady lift response of compliant membrane wings in hovering kinematics by combining analytical inviscid theory with experimental results. An unsteady aerodynamic model is derived for a compliant thin aerofoil immersed in incompressible inviscid flow of variable freestream velocity at high angles of attack. The model, representing a spanwise section of a hovering membrane wing, assumes small membrane deformation and attached flow. These assumptions are supported by experiments showing that passive membrane deformation suppresses flow separation when hovering at angles of attack up to $55^\circ$. An analytically derived expression is obtained for the unsteady lift response, incorporating the classical Wagner and Theodorsen functions and the membrane dynamic response. This theoretical expression is validated against experimental water-tank measurements that are performed on hovering membrane wings at angles of attack of $35^\circ$ and $55^\circ$. Data from membrane deformation measurements is applied to the theoretical lift expression, providing the theoretical lift response prediction for each of the available experimental scenarios. Results of the comparison show that the proposed theory accurately predicts unsteady lift contributions from membrane deformation at high angles of attack, provided the deformation remains small and the flow is attached. This agreement between inviscid theory and experimental measurements suggests that when flow separation is suppressed, the unsteady aerodynamic theory is valid well beyond the typical low angle of attack regime. - oai:arXiv.org:2509.00666v2 - physics.flu-dyn - Wed, 10 Dec 2025 00:00:00 -0500 + DeepMech: A Machine Learning Framework for Chemical Reaction Mechanism Prediction + https://arxiv.org/abs/2509.15872 + arXiv:2509.15872v2 Announce Type: replace +Abstract: Prediction of complete step-by-step chemical reaction mechanisms (CRMs) remains a major challenge. Whereas the traditional approaches in CRM tasks rely on expert-driven experiments or costly quantum chemical computations, contemporary deep learning (DL) alternatives ignore key intermediates and mechanistic steps and often suffer from hallucinations. We present DeepMech, an interpretable graph-based DL framework employing atom- and bond-level attention, guided by generalized templates of mechanistic operations (TMOps), to generate CRMs. Trained on our curated ReactMech dataset (~30K CRMs with 100K atom-mapped and mass-balanced elementary steps), DeepMech achieves 98.98+/-0.12% accuracy in predicting elementary steps and 95.94+/-0.21% in complete CRM tasks, besides maintaining high fidelity even in out-of-distribution scenarios as well as in predicting side and/or byproducts. Extension to multistep CRMs relevant to prebiotic chemistry, demonstrates the ability of DeepMech in effectively reconstructing 2 pathways from simple primordial substrates to complex biomolecules such as serine and aldopentose. Attention analysis identifies reactive atoms/bonds in line with chemical intuition, rendering our model interpretable and suitable for reaction design. + oai:arXiv.org:2509.15872v2 + physics.chem-ph + cs.AI + cs.LG + Thu, 11 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Sonya Tiomkin, Alexander Gehrke + Manajit Das, Ajnabiul Hoque, Mayank Baranwal, Raghavan B. Sunoj - A Probabilistic Framework for Predicting Spatiotemporal Intensity and Variability of Outdoor Thermal Comfort - https://arxiv.org/abs/2509.09468 - arXiv:2509.09468v2 Announce Type: replace -Abstract: Thermal conditions in the urban canopy exhibit stochastic variability driven by varied radiative fluxes and turbulent wind fields, requiring probabilistic rather than deterministic prediction methods. This study presents a probabilistic framework for predicting the spatial and temporal intensity and variability of outdoor thermal comfort in tropical urban environments. The framework integrates ground-measured meteorological data and remote sensing urban morphological data to calculate Physiological Equivalent Temperature (PET), and applies K-means, XGBoost, and Monte Carlo simulations on PET training and inference. The prediction model achieved strong performance, with R2, RMSE, and SMAPE values of 0.93, 0.81 degC, and 1.34% for PET_mean, and 0.85, 0.38 degC, and 10.44% for PET_std, respectively. A case study showed clear spatial heterogeneity of outdoor thermal comfort. Locations with dense tree canopies and vegetated surfaces displayed a normalized percentage of acceptable thermal comfort (NATC) up to 65%, whereas built-up zones dominated by impervious surfaces, such as industrial estates and high-density residential areas, recorded NATC below 30%. Greenery was found to mitigate both the intensity of heat stress and its variability, producing a stable and comfortable microclimate. Daytime PET_std ranged from 4.0-4.5 degC in built-up areas to 1.5-2.0 degC in greenery-covered zones, while nighttime PET_std decreased to 2.2-2.4 degC and 1.2-1.4 degC, respectively. These findings emphasize the critical role of greenery in mitigating thermal variability and enhancing outdoor thermal comfort, while revealing the stochastic nature of thermal comfort across different urban morphologies. - oai:arXiv.org:2509.09468v2 - physics.app-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Forecasting the Future with Yesterday's Climate: Temperature Bias in AI Weather and Climate Models + https://arxiv.org/abs/2509.22359 + arXiv:2509.22359v2 Announce Type: replace +Abstract: AI-based climate and weather models have rapidly gained popularity, providing faster forecasts with skill that can match or even surpass that of traditional dynamical models. Despite this success, these models face a key challenge: predicting future climates while being trained only with historical data. In this study, we investigate this issue by analyzing boreal winter land temperature biases in AI weather and climate models. We examine two weather models, FourCastNet V2 Small (FourCastNet) and Pangu Weather (Pangu), evaluating their predictions for 2020-2025 and Ai2 Climate Emulator version 2 (ACE2) for 1996-2010. These time periods lie outside of the respective models' training sets and are significantly more recent than the bulk of their training data, allowing us to assess how well the models generalize to new, i.e. more modern, conditions. We find that all three models produce cold-biased mean temperatures, resembling climates from 15-20 years earlier than the period they are predicting. In some regions, like the Eastern U.S., the predictions resemble climates from as much as 20-30 years earlier. Further analysis shows that FourCastNet's and Pangu's cold bias is strongest in the hottest predicted temperatures, indicating limited training exposure to modern extreme heat events. In contrast, ACE2's bias is more evenly distributed but largest in regions, seasons, and parts of the temperature distribution where climate change has been most pronounced. These findings underscore the challenge of training AI models exclusively on historical data and highlight the need to account for such biases when applying them to future climate prediction. + oai:arXiv.org:2509.22359v2 + physics.ao-ph + cs.AI + Thu, 11 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by-nc-nd/4.0/ - 10.1016/j.buildenv.2025.114102 - Chen, Shisheng, et al. "A Probabilistic Framework for Predicting Spatiotemporal Intensity and Variability of Outdoor Thermal Comfort." Building and Environment (2025): 114102 - Shisheng Chen, Ruohan Xu, Nyuk Hien Wong, Shanshan Tong, Jiashuo Wang, Matthaios Santamouris + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Jacob B. Landsberg, Elizabeth A. Barnes - Soft x-ray ptychography with SOPHIE: Guide and instrumentation - https://arxiv.org/abs/2509.18805 - arXiv:2509.18805v2 Announce Type: replace -Abstract: Soft x-ray ptychography is becoming a key synchrotron microscopy technique in the fields of condensed matter physics, chemistry, and environmental and life sciences. Its attractiveness across broad disciplinary fields is owed to the favorable combination of high spatial resolution and strong contrast mechanisms. The SOft X-ray Ptychography Highly Integrated Endstation (SOPHIE) at the Swiss Light Source (SLS) was developed to accommodate soft x-ray ptychography experiments requiring high spatial resolution, in addition to high chemical and ferroic sensitivities. An introduction to soft x-ray ptychography with SOPHIE aimed at prospective users is provided. Furthermore, an overview of the instrumentation of SOPHIE is given along with an example of the imaging capabilities, which demonstrate the achievement of a sub-10 nm spatial resolution at a photon energy of 706 eV. - oai:arXiv.org:2509.18805v2 - physics.ins-det - cond-mat.mes-hall - Wed, 10 Dec 2025 00:00:00 -0500 + WTMAD-4: A Fair Weighting Scheme for GMTKN55 + https://arxiv.org/abs/2509.23498 + arXiv:2509.23498v2 Announce Type: replace +Abstract: The GMTKN55 data set is a collection of standard benchmarks used in molecular quantum chemistry that spans small- and large-molecule thermochemistry, reaction barriers, and non-covalent interactions. Herein, we identify a flaw in the weighted mean absolute deviation (WTMAD) definitions commonly used to quantify performance of various electronic-structure methods for the GMTKN55 set, which under-weight some of its component benchmarks by orders of magnitude. A new WTMAD-4 metric is proposed, based on typical errors observed for a set of ten minimally empirical dispersion-corrected density-functional approximations (DFAs), ensuring fair treatment across all benchmarks. The performance of 115 DFAs is then reassessed using WTMAD-4 and we highlight a literature example where a DFA parametrised by minimising WTMAD-2 underperforms for benchmarks marginalised by that metric. + oai:arXiv.org:2509.23498v2 + physics.chem-ph + Thu, 11 Dec 2025 00:00:00 -0500 replace - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1063/5.0303529 - Rev. Sci. Instrum. 96, 123704 (2025) Rev. Sci. Instrum. 96, 123704 (2025) Rev. Sci. Instrum. 96, 123704 (2025) - Tim A. Butcher, Simone Finizio, Lars Heller, Nicholas W. Phillips, Blagoj Sarafimov, Carlos A. F. Vaz, Armin Kleibert, Benjamin Watts, Mirko Holler, J\"org Raabe + http://creativecommons.org/licenses/by/4.0/ + 10.1039/D5CP03741G + Kyle R. Bryenton, Erin R. Johnson - Optimised neural networks for online processing of ATLAS calorimeter data on FPGAs - https://arxiv.org/abs/2510.11469 - arXiv:2510.11469v2 Announce Type: replace -Abstract: A study of neural network architectures for the reconstruction of the energy deposited in the cells of the ATLAS liquid-argon calorimeters under high pile-up conditions expected at the HL-LHC is presented. These networks are designed to run on the FPGA-based readout hardware of the calorimeters under strict size and latency constraints. Several architectures, including Dense, Recurrent (RNN), and Convolutional (CNN) neural networks, are optimised using a Bayesian procedure that balances energy resolution against network size. The optimised Dense, CNN, and combined Dense+RNN architectures achieve a transverse energy resolution of approximately 80 MeV, outperforming both the optimal filtering (OF) method currently in use and RNNs of similar complexity. A detailed comparison across the full dynamic range shows that Dense, CNN, and Dense+RNN accurately reproduce the energy scale, while OF and RNNs underestimate the energy. Deep Evidential Regression is implemented within the Dense architecture to address the need for reliable per-event energy uncertainties. This approach provides predictive uncertainty estimates with minimal increase in network size. The predicted uncertainty is found to be consistent, on average, with the difference between the true deposited energy and the predicted energy. - oai:arXiv.org:2510.11469v2 + ELIGANT-TN -- ELI Gamma Above Neutron Threshold: The Thermal Neutron setup + https://arxiv.org/abs/2510.00042 + arXiv:2510.00042v3 Announce Type: replace +Abstract: Here we present the thermal neutron counter from the ELI Gamma Above Neutron Threshold setup at the Extreme Light Infrastructure - Nuclear Physics. We describe the mechanical design of the setup, the properties of the ${}^{3}$He gas counters, and the hardware data-acquisition electronics and software digital signal processing. The performance of the complete detector array is demonstrated via Geant4 and MCNP simulations, and measurements with typical neutron sources. The analysis procedure for experimental measurements are outlined with a in-beam test experiment with an $\alpha$ beam to measure the ${}^{13}\mathrm{C}(\alpha,\mathrm{n}_{0}){}^{16}\mathrm{O}$ cross-section branching ratios. + oai:arXiv.org:2510.00042v3 physics.ins-det - Wed, 10 Dec 2025 00:00:00 -0500 + nucl-ex + Thu, 11 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Georges Aad, Raphael Bertrand, Lauri Laatu, Emmanuel Monnier, Arno Straessner, Nairit Sur, Johann C. Voigt + P. -A. S\"oderstr\"om, D. L. Balabanski, M. Cuciuc, D. M. Filipescu, I. Gheorghe, A. Ku\c{s}o\u{g}lu, C. Matei, D. Testov, S. Aogaki, H. T. Aslani, L. Capponi, D. Choudhury, G. Ciocan, T. Glodariu, M. Krzysiek, V. Lelasseux, R. Roy, R. F. Andrei, M. Brezeanu, R. Corbu, A. Dhal, D. Iancu, D. Kahl, S. Ioannidis, K. KeunHwan, G. Lorusso, B. Mauyey, T. Petruse, G. V. Turturic\u{a} - Latent Spaces for Langevin Dynamics - https://arxiv.org/abs/2510.25773 - arXiv:2510.25773v2 Announce Type: replace -Abstract: In the field of machine learning coarse-grained potentials in molecular dynamics, many propagators require that the effective Hamiltonian is quadratic in momentum, thus limiting the family of coarse-graining functions. In this paper, we derive a general family of coarse-graining embedding functions for which Langevin dynamics samples correctly. These equations have significant implications for molecular simulations and pave the way for Langevin dynamics on non-geometric coarse-graining representations, such as those provided by principal components of component analysis or latent embeddings of molecules obtained from neural networks. - oai:arXiv.org:2510.25773v2 + Enhancing NMR Shielding Predictions of Atoms-in-Molecules Machine Learning Models with Neighborhood-Informed Representations + https://arxiv.org/abs/2510.05623 + arXiv:2510.05623v2 Announce Type: replace +Abstract: Accurate prediction of nuclear magnetic resonance (NMR) shielding with machine learning (ML) models remains a central challenge for data-driven spectroscopy. We present atomic variants of the Coulomb matrix (aCM) and bag-of-bonds (aBoB) descriptors, and extend them using radial basis functions (RBFs) to yield smooth, per-atom representations (aCM-RBF, aBoB-RBF). Local structural information is incorporated by augmenting each atomic descriptor with contributions from the n nearest neighbors, resulting in the family of descriptors, aCM-RBF(n) and aBoB-RBF(n). For 13C shielding prediction on the QM9NMR dataset (831,925 shielding values across 130,831 molecules), aBoB-RBF(4) achieves an out-of-sample mean error of 1.69 ppm, outperforming models reported in previous studies. While explicit three-body descriptors further reduce errors at a higher cost, aBoB-RBF(4) offers the best balance of accuracy and efficiency. Benchmarking on external datasets comprising larger molecules (GDBm, Drug12/Drug40, and pyrimidinone derivatives) confirms the robustness and transferability of aBoB-RBF(4), establishing it as a practical tool for ML-based NMR shielding prediction. + oai:arXiv.org:2510.05623v2 physics.chem-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - Andy Bruce, Alexander Aghili, Razvan Marinescu, Daniel Sabo + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Surajit Das, Raghunathan Ramakrishnan - Adiabatic Electron Transfer in the Barrierless and Marcus-Inverted Regimes - https://arxiv.org/abs/2511.01909 - arXiv:2511.01909v3 Announce Type: replace -Abstract: Here it is shown that in the adiabatic limit of condensed-phase electron transfer, the onset of barrierless transition occurs at a lower driving force than predicted by the non-adiabatic Marcus formulation. Furthermore, in the adiabatic limit of the Marcus-inverted region, the standard mechanism of electron transfer becomes topologically forbidden. This behavior arises from a topological change in the mapping between the adiabatic and diabatic electronic surfaces, emerging precisely at the onset of the Marcus-inverted region. In this case, alternative mechanisms such as tunneling and non-radiative decay may dominate the rate, typically orders of magnitude slower than the rate calculated from Marcus theory. - oai:arXiv.org:2511.01909v3 - physics.chem-ph - cond-mat.mes-hall - cond-mat.mtrl-sci + ChemGen: Code Generation for Multispecies Chemically Reacting Flow Simulations + https://arxiv.org/abs/2510.10005 + arXiv:2510.10005v3 Announce Type: replace +Abstract: This paper introduces ChemGen, a software package that uses code generation to integrate multispecies thermodynamics and chemical kinetics into C+-based computational physics codes. ChemGen aims to make chemical kinetics more accessible in existing simulation frameworks and help bridge the gap between combustion modeling and computational physics. The package employs the concept of decorators which enable flexible C++ code generation to target established software ecosystems. ChemGen generates code to evaluate thermodynamic properties, chemical source terms, and their analytical derivatives for Jacobian calculations. Also included are a variety of implicit time integration schemes, linear solvers, and preconditioners. The various components of Chemgen are verified by demonstrating agreement with Cantera and/or theoretical convergence rates. Finally, we integrate ChemGen into OpenFOAM and achieve a speedup over its native chemistry solver by approximately four times. ChemGen is an ongoing project released under the NRL Open License, a source-available license provided by the U.S. Naval Research Laboratory. + oai:arXiv.org:2510.10005v3 + physics.comp-ph + Thu, 11 Dec 2025 00:00:00 -0500 + replace + http://creativecommons.org/publicdomain/zero/1.0/ + Ryan F. Johnson, Eric J. Ching, Ethan S. Genter, Joshua E. Lipman, Andrew D. Kercher, Jay Arcities, Hai Wang + + + Optical-field-induced dips and splits in nonlinear spectra of selective reflection from high-density atomic vapor + https://arxiv.org/abs/2510.15100 + arXiv:2510.15100v2 Announce Type: replace +Abstract: We discuss nonlinear spectra of selective reflection from high-density rubidium atomic vapor, where the self-broadening of the resonant transition $5S_{1/2}-5P_{3/2}$ dominates over the Doppler width. In the experiments, the hole-burning technique with probe and pump lasers is used. The reflection of weak probe beam is investigated at four atomic densities in the range $(1.2\text{--}3.6)\times10^{17}$~cm$^{-3}$ and various pump beam intensities. To enhance the spectral resolution, the frequency derivative $\text{d}R/\text{d}\nu$ of the reflection coefficient $R$ is analyzed. Increasing the atomic number density changes the character of self-broadening from inhomogeneous to homogeneous. At the highest density, the strong pump field splits the observed spectra into two homogeneously broadened symmetric resonances. The appearance of the optical-field-induced resonances can be explained within the framework of "dressed atomic states" approach. At lower densities the spectral profiles are inhomogeneously broadened. Spectral profiles of the frequency derivative are separated by optically saturated dips. The width of such dips is a combination of the homogeneous component of self-broadening and intensity-dependent field broadening. Careful study of the transition from inhomogeneous to homogeneous broadening may initiate further development of the theory of interatomic interactions in high density atomic gas media. + oai:arXiv.org:2510.15100v2 + physics.atom-ph + Thu, 11 Dec 2025 00:00:00 -0500 + replace + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + V. A. Sautenkov, S. A. Saakyan, A. A. Bobrov, B. B. Zelener + + + Optimized Single-Core PCF-Based SPR Biosensor for High-Performance Early-Stage Multi-Cancer Detection + https://arxiv.org/abs/2510.17283 + arXiv:2510.17283v2 Announce Type: replace +Abstract: In this study, we present a highly sensitive Surface Plasmon Resonance (SPR)-based biosensor integrated with a circular-lattice Photonic Crystal Fiber (PCF) for early-stage cancer detection. The proposed sensor leverages the synergy between SPR and PCF technologies to overcome the bulkiness and limited sensitivity of traditional SPR systems. A thin gold (Au) layer, responsible for plasmon excitation, is deposited on the fiber structure, while a nanolayer of vanadium pentoxide (V2O5) is introduced to enhance adhesion between the gold and the silica background, improving structural stability and field confinement. The sensor is designed to detect refractive index (RI) variations in biological analytes, specifically targeting cancerous cells from skin, blood, and adrenal gland tissues. The optical characteristics and performance of the sensor were thoroughly analyzed using the Finite Element Method (FEM) in COMSOL Multiphysics 6.1, allowing for precise simulation and optimization. The sensor demonstrates high sensitivity within the RI range of 1.360-1.395, corresponding to the RI values of the target cancer cells. Remarkable wavelength sensitivities of 21,250 nm/RIU, 53,571 nm/RIU, and 103,571 nm/RIU were achieved for skin, blood, and adrenal gland cancers, respectively. In addition, a maximum figure of merit (FOM) of 306.424 RIU^-1 and a spectral resolution (SR) of 9.57x10^-7 RIU further affirm the sensor's exceptional detection capabilities. These findings indicate the proposed SPR-PCF sensor's strong potential for real-time, label-free biosensing applications, particularly in precise and early cancer diagnostics. + oai:arXiv.org:2510.17283v2 + physics.med-ph + physics.comp-ph + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 + replace + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Tonmoy Malakar, Miss Nourin Nurain Amina, Zarin Tasnim Nijhum, Nazmus Shakib Lalin + + + Spatial and temporal study of the post-compressed high-power laser pulses for coherent extreme ultraviolet source development + https://arxiv.org/abs/2510.26472 + arXiv:2510.26472v2 Announce Type: replace +Abstract: We compared the performance of two post-compression techniques, a gas-filled hollow-core fiber (HCF) and a multi-pass cell (MPC), using a high-power ytterbium-doped fiber laser. The HCF produced 27 fs pulses from 230 fs inputs at >50% efficiency, whereas the MPC achieved 34 fs pulses with significantly higher efficiency (>88%). Both results aligned well with numerical simulations. Crucially, spatial wavefront analysis revealed that the HCF acts as a modal filter, improving beam quality, whereas the MPC introduces aberrations through cumulative mirror errors. Furthermore, we characterize the photon flux of high harmonic generation driven by the post-compressed pulses from the HCF and MPC. These finding highlights that post-compression technique based on self-phase modulation is efficient for the intensity boosting of femtosecond laser system, providing opportunities for generating high quality extreme ultraviolet (XUV) sources. In addition, further improvement of spatial wavefront quality is suggested using the HCF as a single compressor or output component of the cascade compressor. + oai:arXiv.org:2510.26472v2 + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 + replace + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Cong Zhou, Haina Wu, Chaoneng Wu, Yitong Zhao, Chen Wang, Jiayue Liu, Zige Qiu, Wei Zhang, Yapei Peng, Mingyuan Shi, Shuyuan Hu, Xiaoliang Liu, Sizhong Wu, Jie Yang, Cangtao Zhou, Lu Li + + + Model-independent determination of nuclear charge radii from Li-like ions + https://arxiv.org/abs/2510.27427 + arXiv:2510.27427v2 Announce Type: replace +Abstract: We demonstrate that recent advances in QED theory of Li-like ions [V. A. Yerokhin et al., Phys. Rev. A 112, 042801 (2025)] enable determinations of absolute nuclear charge radii for heavy elements. By incorporating constraints derived from electron-scattering data, we obtain radii that are independent of the assumed model of the nuclear charge distribution. Our approach is validated for $^{208}$Pb, a well-studied spherical nucleus, and is then applied to $^{209}$Bi, where low-lying nuclear excitations complicate the interpretation of muonic-atom data. + oai:arXiv.org:2510.27427v2 + physics.atom-ph + hep-ex + nucl-th + Thu, 11 Dec 2025 00:00:00 -0500 + replace + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + V. A. Yerokhin, B. Ohayon + + + Quantum-coherent optical isolation and circulation using frequency conversion on a chip + https://arxiv.org/abs/2511.00570 + arXiv:2511.00570v2 Announce Type: replace +Abstract: Breaking optical reciprocity enables new regimes of light--matter interaction with broad implications for fundamental physics and emerging quantum technologies. Although various approaches have been explored to achieve optical nonreciprocity, realizing it at the single-photon level has remained a major challenge. Here, we demonstrate nonmagnetic optical nonreciprocity -- including both isolation and circulation -- in the quantum regime, enabled by efficient and noiseless all-optical frequency conversion on an integrated III-V photonic chip. Our device preserves the quantum coherence and entanglement of the input photons while delivering exceptional performance parameters, including a high extinction ratio of 34 dB, low insertion loss of 0.8 dB, broad bandwidth of 44 GHz, high operational fidelity of 97%, and widely tunable operation wavelength. This realization of quantum optical nonreciprocity in a scalable photonic platform opens a pathway toward directional quantum communication and noise-resilient quantum networks. + oai:arXiv.org:2511.00570v2 + physics.optics quant-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - Ethan Abraham + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Jierui Hu, Hao Yuan, Joshua Akin, Shanhui Fan, Kejie Fang - Report on the Scoping Workshop on AI in Science Education Research 2025 - https://arxiv.org/abs/2511.14318 - arXiv:2511.14318v3 Announce Type: replace -Abstract: This report summarizes the outcomes of a two-day international scoping workshop on the role of artificial intelligence (AI) in science education research. As AI rapidly reshapes scientific practice, classroom learning, and research methods, the field faces both new opportunities and significant challenges. The report clarifies key AI concepts to reduce ambiguity and reviews evidence of how AI influences scientific work, teaching practices, and disciplinary learning. It identifies how AI intersects with major areas of science education research, including curriculum development, assessment, epistemic cognition, inclusion, and teacher professional development, highlighting cases where AI can support human reasoning and cases where it may introduce risks to equity or validity. The report also examines how AI is transforming methodological approaches across quantitative, qualitative, ethnographic, and design-based traditions, giving rise to hybrid forms of analysis that combine human and computational strengths. To guide responsible integration, a systems-thinking heuristic is introduced that helps researchers consider stakeholder needs, potential risks, and ethical constraints. The report concludes with actionable recommendations for training, infrastructure, and standards, along with guidance for funders, policymakers, professional organizations, and academic departments. The goal is to support principled and methodologically sound use of AI in science education research. - oai:arXiv.org:2511.14318v3 - physics.ed-ph - cs.CY - Wed, 10 Dec 2025 00:00:00 -0500 + van de Hulst Essay: Geometric-phase portrayal of electromagnetic scattering by a three-dimensional object in free space + https://arxiv.org/abs/2511.15670 + arXiv:2511.15670v2 Announce Type: replace +Abstract: The concept of geometric phase was applied to initiate the geometric-phase portrayal of electromagnetic scattering by a three-dimensional object in free space. Whereas the incident electromagnetic field is that of an arbitrarily polarized plane wave, the direction-dependent far-zone scattering amplitude is used to define + direction-dependent Stokes parameters for the scattered field. Both symmetric and asymmetric Poincar\'e spinors are formulated to characterize the polarization states of incident plane wave and the far-zone scattering amplitude, and two different geometric phases are defined therefrom. Density plots of both geometric phases were calculated for six different homogeneous isotropic spheres with different linear constitutive properties and boundary conditions: dielectric-magnetic spheres (non-dissipative and dissipative), impedance spheres, perfect electrically conducting spheres, charged dielectric-magnetic spheres, dielectric-magnetic spheres with topologically insulating surface states, and isotropic chiral spheres. The incident plane waves were taken to be linearly and circularly polarized, for the sake of illustration. Numerical results revealed that geometric-phase density plots possess significantly richer features than their counterparts for the differential scattering efficiency. The geometric-phase portrayals exhibit enhanced sensitivity to changes in the size and composition of the scatterer, the boundary conditions, and the incident polarization state, suggesting promise for inverse-scattering problems. + oai:arXiv.org:2511.15670v2 + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Marcus Kubsch, Marit Kastaun, Peter Wulff, Nicole Graulich, Moriah Ariely, Alexander Bergmann-Gering, Sebastian Gombert, Bor Gregorcic, Hendrik H\"artig, Benedikt Heuckmann, Andrea Horbach, Christina Krist, Gerd Kortemeyer, Ben M\"unch, Samuel Pazicni, Joshua M. Rosenberg, Sascha Schanze, Gena Sbeglia, Vidar Skogvoll, Christophe Speroni, Christoph Thyssen, Lars-Jochen Thoms, Brandon J. Yik, Xiaoming Zhai + http://creativecommons.org/licenses/by/4.0/ + Akhlesh Lakhtakia - On the analytical behavior of the $k$--$\omega$ turbulence model in buoyant-driven thermal convection - https://arxiv.org/abs/2512.01308 - arXiv:2512.01308v3 Announce Type: replace -Abstract: The representation of buoyancy-driven turbulence in Reynolds-averaged Navier--Stokes models remains unresolved, with no widely accepted standard formulation. A key difficulty is the lack of analytical guidance for incorporating buoyant effects, particularly under unstable stratification. This study derives an analytical solution of the standard $k$--$\omega$ model for Rayleigh--B\'enard convection in an infinite layer, where turbulent kinetic energy is generated solely by buoyancy. The solution provides explicit scaling relations among the Rayleigh ($\mathit{Ra}$), Prandtl ($\mathit{Pr}$), and Nusselt ($\mathit{Nu}$) numbers that capture the simulation trends: $\mathit{Nu} \sim \mathit{Ra}^{1/3}\mathit{Pr}^{1/3}$ for $\mathit{Pr} \ll 1$ and $\mathit{Nu} \sim \mathit{Ra}^{1/3}\mathit{Pr}^{-0.415}$ for $\mathit{Pr} \gg 1$. This framework quantifies the discrepancies in the conventional buoyancy treatment and clarifies their origin. Informed by this analysis, the buoyancy-related modelling terms are reformulated to recover the measured $\mathit{Nu}$--$\mathit{Ra}$--$\mathit{Pr}$ trends. Only two dimensionless algebraic functions are introduced, which vanish in the absence of buoyancy, ensuring full compatibility with the standard closure. The corrected model is validated across a range of buoyancy-driven flows, including two-dimensional Rayleigh--B\'enard convection, internally heated convection in two configurations, unstably stratified Couette flow, and vertically heated natural convection with varying aspect ratios. Across all cases, it provides highly accurate predictions. - oai:arXiv.org:2512.01308v3 + Self-similar multishock implosions for ultrahigh compression of matter + https://arxiv.org/abs/2512.00827 + arXiv:2512.00827v2 Announce Type: replace +Abstract: We present a class of self-similar solutions describing ultrahigh compression of a uniform-density target by spherically converging, stacked shock waves. Extending the classical Guderley model, we derive a scaling law for the final density of the form $\rho_{r}/\rho_{0} \propto \hat{P}^{\beta (N-1)}$, where $N$ is the number of shocks, $\hat{P}$ the stage pressure ratio, and $\beta$ a numerical exponent determined by the adiabatic index $\gamma$. One-dimensional hydrodynamic simulations confirm the validity of this scaling across a broad parameter range. Notably, the relation remains accurate even in the strongly nonlinear regime up to $\hat{P} \sim 70$, well beyond the perturbative limit, highlighting the robustness and practical relevance of the model. Owing to its volumetric geometry, this compression scheme inherently avoids the Rayleigh--Taylor instability, which typically compromises shell-based implosions, and thereby establishes a theoretical benchmark for instability-free compression in inertial confinement fusion. + oai:arXiv.org:2512.00827v2 physics.flu-dyn - Wed, 10 Dec 2025 00:00:00 -0500 + physics.plasm-ph + Thu, 11 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - Da-Sol Joo + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + 10.1103/bbvn-x95v + Physical Review E 112, 055206 (2025) + M. Murakami - Granite sliding on granite: friction, wear rates, surface topography, and the scale-dependence of rate-state effects - https://arxiv.org/abs/2512.01765 - arXiv:2512.01765v2 Announce Type: replace -Abstract: We study tribological granite-granite contacts as a model for tectonic faulting, combining experiments, theory, and molecular dynamics simulations. The high friction in this system is not dominated by particulate wear or plowing, as frequently assumed, but by cold welding within plastically deformed asperity junctions. We base this conclusion on the observation that wear is repeatedly high after cleaning contacts but decreases as gouge accumulates, while friction shows the opposite trend. Moreover, adding water reduces wear by a factor of ten but barely decreases friction. Thermal and rate-dependent effects - central to most earthquake models-are negligible: friction remains unchanged between -40{\deg}C and 20{\deg}C, across abrupt velocity steps, and after hours of stationary contact. The absence of rate-state effects in our macroscopic samples is rationalized by the scale-dependence of pre-slip. The evolution of surface topography shows that quartz grains become locally smooth, with height spectra isotropic for wavelength below 10 microns but anisotropic at longer wavelengths, similar to natural faults. The resulting gouge particles have the usual characteristic sizes near 100 nm. Molecular dynamics simulations of a rigid, amorphous silica tip sliding on {\alpha}-quartz reproduce not only similar friction coefficients near unity but also other experimentally observed features, including stress-introduced transitions to phases observed in post-mortem faults, as well as theoretical estimates of local flash temperatures. Additionally, they reveal a marked decrease of interfacial shear strength above 600{\deg}C. The overall correspondence between experiments, simulations, theory, and field observations indicates that our model system captures essential aspects of rock friction. - oai:arXiv.org:2512.01765v2 - physics.geo-ph - cond-mat.mtrl-sci - physics.comp-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Drag reduction via separation control using plasma actuators on a truck cabin side + https://arxiv.org/abs/2512.03613 + arXiv:2512.03613v2 Announce Type: replace +Abstract: We investigate the drag reduction on a heavy-duty vehicle using dielectric-barrier discharge plasma actuators located on the A-pillars. An experimental campaign is carried out on a generalized truck model, the Ground Transportation System (GTS), which is known for its lateral separation bubbles on both sides of the truck's cabin. Measurements are performed for several yaw angles up to $7.5\degree$. Actuation is applied individually on the leeward and windward sides as well as simultaneously. Load cell measurements show that the plasma actuators effectively reduce the axial force on the GTS, with symmetric actuation achieving the highest reduction. Leeward actuation demonstrates greater control authority than the windward one; at large yaw angles the latter has a negligible effect on the axial force. Regarding side force, the leeward actuation produces a drop in its magnitude while windward actuation produces an increase. Interestingly, actuating symmetrically also augments the side force. Particle image velocimetry reveals that the plasma actuator causes a reduction in the length and width of the separation bubble on the cabin side, reducing the apparent frontal area of the truck and thus its drag. Under crosswind conditions, the stronger authority of the leeward actuator is explained by the larger separation bubble. The side force variation is driven by the net lateral suction force, which correlates with the size of the lateral recirculation regions controlled by the actuators. + oai:arXiv.org:2512.03613v2 + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Sergey V. Sukhomlinov, Martin H. M\"user, B. N. J. Persson + Lucas Schneeberger, Stefano Discetti, Andrea Ianiro - Calendar Time Local Earthquake Forecasts from Earthquake Nowcasts: A Do-It-Yourself (DIY) Ensemble Method - https://arxiv.org/abs/2512.06572 - arXiv:2512.06572v2 Announce Type: replace -Abstract: A previous paper discussed a method that builds on local earthquake nowcasts to produce fixed natural time forecasts, where natural time represents counts of small earthquakes since the last large earthquake. In this second paper we extend the natural time forecast to calendar time forecasts using an ensemble approach. The Gutenberg-Richter (GR) magnitude-frequency relation, which was the basis for both methods, states that for every large target earthquake of magnitude greater than MT , there are on average NGR small earthquakes of magnitude MS. The only assumption in our method is that the statistics of the local region are the same as in the larger surrounding regions. The method has significant skill, as defined by the Receiver Operating Characteristic (ROC) test, which improves as time since the last major earthquake increases. The probability is conditioned on the number of small earthquakes n(t) that have occurred since the last large earthquake. We do not need to assume a probability model, the probability is instead computed directly as the Positive Predictive Value (PPV) associated with the ROC curve. We find that for short time intervals (months), the forecast shows strong main shock clustering, followed by a gradual buildup of probability over the following years leading to the next large earthquake ("elastic rebound"). We apply the method to the same local region as in our first paper around Los Angeles, California, following the January 17, 1994 magnitude M6.7 Northridge earthquake. - oai:arXiv.org:2512.06572v2 - physics.geo-ph - Wed, 10 Dec 2025 00:00:00 -0500 + How Conflict Aversion Can Enable Authoritarianism: An Evolutionary Dynamics Approach + https://arxiv.org/abs/2512.06245 + arXiv:2512.06245v2 Announce Type: replace +Abstract: We use evolutionary game theory to examine how conflict-averse centrism can facilitate authoritarian success in polarized political conflicts. Such conflicts are often asymmetric: authoritarian actors can employ norm-breaking or coercive tactics, while democratic resistance faces stronger normative constraints on acceptable behavior. Yet formal models typically treat sides symmetrically and rarely examine conflict-averse behavior. Drawing on empirical research on protest backlash, civility norms, and authoritarian resilience, we model these dynamics as a three-strategy evolutionary game. This framework yields two outcomes -- cyclic authoritarian resurgence through a heteroclinic cycle and a stable centrist--authoritarian coalition excluding resistance -- depending on confrontation responses. We demonstrate how an established dynamical framework with empirically grounded behavioral assumptions clarifies conditions under which conflict aversion can diminish the effectiveness of democratic resistance. + oai:arXiv.org:2512.06245v2 + physics.soc-ph + nlin.AO + q-bio.PE + Thu, 11 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - John B Rundle, Ian Baughmann, Andrea Donnellan, Lisa Grant Ludwig, Geoffrey C Fox, Kazuyoshi Nanjo + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Chad M. Topaz - A Capacitor Model of the Helical Deflector: Revisiting Shamaev's Proposal and the Model in the Book - https://arxiv.org/abs/2512.06651 - arXiv:2512.06651v2 Announce Type: replace -Abstract: A RF helical deflector is a type of electron and ion optics device that applies a time-dependent rotating transverse electric or magnetic field by means of time-dependent RF voltage applied on two opposite conducting helical structures (wires, ribbons or other) to deflect charged particles (a single, bunch or beam) in a circular or spiral path. It is a perspective indirect timing system being concurrent for reaching picosecond time resolution, and have promise being excellent candidate for high precision time-of-flight detection. As a timing system, it converts the temporal structure of an electron beam into a spatial pattern -- particularly, an ellipse in the case of a single-frequency RF voltage and continuous electron pencil beam. - I propose a capacitor model of a RF helical deflector and compare it with the existing model in the Book, interpret it and provide understanding of it. Furthermore, I analyze the latter, finding analytical formulas for the applied electric field, ellipse sizes (semi-axes) and rotation angle, lengths of the ellipse line, corresponding to the duration of electron pencil bunches or beams. The present article touches the topics of getting circle on resonance limit and of deflection sensitivity. - oai:arXiv.org:2512.06651v2 - physics.acc-ph + An Euler-Lagrangian Multiphysics Coupling Framework for Particle-Laden High-Speed Flows + https://arxiv.org/abs/2512.06548 + arXiv:2512.06548v2 Announce Type: replace +Abstract: Particle-laden effects in high-speed flows require a coupled Euler and Lagrangian prediction technique with varying fidelity of thermochemical models, depending on the simulation conditions of interest. This requirement makes the development of a conventional monolithic solver challenging to manage the different fidelity of the thermochemical models within a single computational framework. To address this, the present study proposes a multi-solver framework for the coupled Euler-Lagrangian predictions applicable to various particle-laden high-speed flow conditions. Volumetric and surface couplings are established between a particle solver ORACLE (OpenFOAM-based lagRAngian CoupLEr) and a thermochemical nonequilibrium flow solver based on an adaptable data exchange algorithm. The developed framework is then validated by predicting particle-laden supersonic nozzle flows and aerothermal heating around a hypersonic Martian atmospheric entry capsule. Finally, a quasi-1D approximation is proposed in conjunction with a surrogate method to efficiently and accurately predict particle-laden surface erosion, with quantified parametric uncertainty, for hypersonic aerothermal characterization. + oai:arXiv.org:2512.06548v2 + physics.flu-dyn physics.app-ph - physics.class-ph - physics.ins-det - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 + replace + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Hyeon Woo Nam, Tae Woong Jeong, Sung Min Jo + + + Kinetic Alfv\'en waves in the temperature anisotropic space plasma with a kappa-Maxwellian distribution + https://arxiv.org/abs/2512.07893 + arXiv:2512.07893v2 Announce Type: replace +Abstract: The dispersion and damping rate of kinetic Alfv\'en waves are studied in temperature anisotropic space plasma with kappa-Maxwellian distribution. Employing a kinetic approach, the wave frequency and damping rate of kinetic Alfv\'en waves and the modified ion acoustic waves are derived in a low \b{eta} plasma, which both depend on the parameters \k{appa} and . The numerical analyses show that the wave frequency of kinetic Alfv\'en waves is larger in kappa-Maxwellian plasma than that in Maxwellian case. The wave frequency of the modified ion acoustic waves in kappa-Maxwellian plasma is larger in the short-wave region but smaller in the long-wave region than that in Maxwellian case. Again, we found that the damping rate of kinetic Alfv\'en waves in kappa-Maxwellian plasma is stronger than that in Maxwellian case. The damping rate of modified ion acoustic waves in kappa-Maxwellian plasma is stronger in the short-wave region but weaker in the long-wave region than that in Maxwellian case. The impact of the parameter on the two modes is relatively small because we consider the low \b{eta} case. These results are helpful for us to understand better the characteristics of kinetic Alfv\'en waves in space plasma. + oai:arXiv.org:2512.07893v2 + physics.plasm-ph + physics.space-ph + Thu, 11 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Hayk L. Gevorgyan + Chin. J. Phys. 90 (2024) 199 + Rui Huo, Jiulin Du, Ran Guo - ExPUFFIN: Thermodynamic Consistent Viscosity Prediction in an Extended Path-Unifying Feed-Forward Interfaced Network - https://arxiv.org/abs/2512.06927 - arXiv:2512.06927v2 Announce Type: replace -Abstract: Accurate prediction of liquid viscosity is essential for process design and simulation, yet remains challenging for novel molecules. Conventional group-contribution models struggle with isomer discrimination, large molecules, and parameter availability, while purely data-driven graph neural networks (GNNs) demand large datasets and offer limited interpretability. Even when feasible to be applied, purely data-driven models lack thermodynamic consistency in their predictions and are not a reliable solution. This work introduces ExPUFFIN, an extended version of the Path-unifying Feed-Forward Interfaced Network, consisting of a hybrid GNN-based framework that directly predicts temperature-dependent viscosities of pure hydrocarbons from molecular graphs, while enforcing mechanistic inductive biases in the output layer to ensure thermodynamic consistency. Molecular information is given as graph structures, encoded as a graph convolutional network, and mapped to an inductive bias neuron based on two thermophysical correlations: a three-parameter Andrade-type equation and a four-parameter empirical viscosity-temperature relation. The accuracy of these models is compared with a solely data-driven prediction. The Andrade-based ExPUFFIN variant reduces RMSE compared to the purely data-driven baseline of 37 percent and yields smooth, physically consistent interpolation and extrapolation of viscosity-temperature curves, properties that are not observed in purely data-driven models. The empirical ExPUFFIN model provides comparable accuracy while retaining robust trends. Overall, embedding physics-based structure in GNN outputs improves accuracy, robustness, and transferability, enabling reliable viscosity predictions for complex hydrocarbon molecules. The approach is readily extendable to other properties and significantly broader chemical domains. - oai:arXiv.org:2512.06927v2 - physics.chem-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Firehose instability in the space plasma with anisotropic Cairns-distribution electrons + https://arxiv.org/abs/2512.07894 + arXiv:2512.07894v2 Announce Type: replace +Abstract: We study the electron firehose mode propagating parallel to the ambient magnetic field in the space plasma with anisotropic Cairns-distribution electrons. The dispersion relation, the wave frequency and the growth rate of electron firehose mode are derived, and the condition for onset of the firehose instability is obtained. We show that the wave frequency and the growth rate both depend significantly on the parameters, such as the parallel electron beta , the nonthermal parameter {\Lambda} and the electron temperature anisotropy Ae , and the anisotropic Cairns-distribution electrons change the instability condition. The numerical analyses show that the wave frequency and the growth rate of the electron firehose mode increase with increase of the parameters. The results may be helpful for understanding the firehose instability in space plasma environments. + oai:arXiv.org:2512.07894v2 + physics.plasm-ph + physics.space-ph + Thu, 11 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by-nc-sa/4.0/ - Carine Menezes Rebello, Ulderico Di Caprio, Jenny Steen-Hansen, Bruno Rodrigues, Erbet Almeida Costa, Anderson Rapello dos Santos, Flora Esposito, Mumin Enis Leblebici, Idelfonso B. R. Nogueira + http://creativecommons.org/licenses/by/4.0/ + Eur. Phys. J. Plus. 139 (2024) 604 + Rui Huo, Jiulin Du - Mapping Still Matters: Coarse-Graining with Machine Learning Potentials - https://arxiv.org/abs/2512.07692 - arXiv:2512.07692v2 Announce Type: replace -Abstract: Coarse-grained (CG) modeling enables molecular simulations to reach time and length scales inaccessible to fully atomistic methods. For classical CG models, the choice of mapping, that is, how atoms are grouped into CG sites, is a major determinant of accuracy and transferability. At the same time, the emergence of machine learning potentials (MLPs) offers new opportunities to build CG models that can in principle learn the true potential of the mean force for any mapping. In this work, we systematically investigate how the choice of mapping influences the representations learned by equivariant MLPs by studying liquid hexane, amino acids, and polyalanine. We find that when the length scales of bonded and nonbonded interactions overlap, unphysical bond permutations can occur. We also demonstrate that correctly encoding species and maintaining stereochemistry are crucial, as neglecting either introduces unphysical symmetries. Our findings provide practical guidance for selecting CG mappings compatible with modern architectures and guide the development of transferable CG models. - oai:arXiv.org:2512.07692v2 - physics.chem-ph - q-bio.BM - Wed, 10 Dec 2025 00:00:00 -0500 + Ion-acoustic shock and solitary waves in magnetized plasma with Cairns-Gurevich distribution electrons + https://arxiv.org/abs/2512.07895 + arXiv:2512.07895v2 Announce Type: replace +Abstract: The propagation properties of ion-acoustic solitary and shock waves in the magnetized viscous plasma with nonthermal trapped electrons are investigated. The Cairns-Gurevich distribution as the electron distribution is considered to describe the plasma nonthermality and particle trapping. By adopting the reductive perturbation technique, we derived the nonlinear Schamel-Korteweg-de Vries-Burgers (SKdVB) equation, and then obtained the ion-acoustic shock and solitary wave solutions of the SKdVB equation for different limiting cases. It is found that the impact of nonthermal parameter {\alpha}, external magnetic field {\Omega}, obliqueness lz, wave speed U0, and the ion kinematic viscosity {\eta}0 can significantly change the characteristics of the shock and solitary waves. These results may be useful for better understanding the propagation of nonlinear structures in space (i.e. Earth's magnetosphere and ionosphere, auroral regions) and laboratory plasma with nonthermal trapped electrons. + oai:arXiv.org:2512.07895v2 + physics.plasm-ph + physics.space-ph + Thu, 11 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Franz G\"orlich, Julija Zavadlav + Commun. Theor. Phys. 77 (2025) 065501 + Rui Huo, Jiulin Du - VO2 films grown on TiO2 sub-layer: influence of thickness on structural, electrical and optical properties - https://arxiv.org/abs/2411.14920 - arXiv:2411.14920v2 Announce Type: replace-cross -Abstract: Vanadium dioxide with metal-to-insulator transition (MIT) that is triggered by heat, current or light is a promising material for modern active THz/mid-IR metasurfaces and all-optical big data processing systems. Multilayer VO2-based active metasurfaces are urgently needed however several important issues related to VO2 properties in VO2/TiO2/Al2O3 films should be thoroughly examined first. We study electrical, optical and structural properties of VO2 films as well as their composition and switching characteristics as function of the VO2 layer thickness in VO2/TiO2 composites. XRD analysis revealed an epitaxial growth of films with deformation of the monoclinic VO2 lattice to hexagonal symmetry. Reduced VO2 layer thickness from 170 nm to 20 nm results in increased phase transition temperature while the width of the resistance versus temperature hysteresis loop R(T) remains constant at ~6C for all VO2 thicknesses in the range of 20-170 nm. The resistance alteration ratio is reduced from 4.2e3 to 2.7e2 in thinner films. Raman spectra reveal a significant shift of VO2 lattice vibration modes for films thinner than 30 nm claiming a great structural strain whereas modes position for thicker VO2 layers are similar to those in bulk structure. Composition of VO2 films has revealed only a minor alteration of VO2/V2O5 phases ratio from 1.6 to 1.8 when the film thickness has been increased from 20 nm to 50 nm. Investigation of surface elemental composition and valence states of VO2 films revealed that VO2/V2O5 ratio remains practically unchanged with thickness reduction. The study of electrical MIT dynamics revealed the switching time of a 50 nm VO2 film to be as low as 800 ns. - oai:arXiv.org:2411.14920v2 - cond-mat.mtrl-sci + Critical Thresholds in Non-Pharmaceutical Interventions for Epidemic Control + https://arxiv.org/abs/2512.08339 + arXiv:2512.08339v2 Announce Type: replace +Abstract: Non-pharmaceutical interventions, such as contact tracing and social distancing, are critical for controlling epidemic outbreaks, yet their dynamic interactions remain underexplored. We introduce a probabilistic framework to analyze the synergy between contact tracing speed, quantified by the contact tracing period $\tau$, and the average number of close contacts, $\bar{k}_+$, reflecting social distancing measures. We identify critical thresholds ($R=1$) that separate pandemic and contained phases in the $\bar{k}_{+}-\tau$ plane, validated using high-resolution data from Shenzhen's 2022 Omicron outbreak (1,187 cases, 86,451 contacts). Our findings show that contact tracing alone can contain diseases with $R_0 < 2.12$ (95% CI 2.07-2.16), covering 43.33% of major infectious diseases, while combining with social distancing extends control to $R_0 < 7.82$ (95% CI 7.70-7.93), encompassing 86.67% of pathogens. These results, supported by empirical data, highlight the efficacy of rapid tracing and targeted social distancing as alternatives to mass PCR testing. Our framework offers actionable insights for optimizing NPI strategies, though challenges in scaling to regions with higher tracing miss rates or weaker infrastructure underscore the need for adaptive, data-driven policies. + oai:arXiv.org:2512.08339v2 + physics.soc-ph + Thu, 11 Dec 2025 00:00:00 -0500 + replace + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Jinghui Wang, Yutian Zeng, Cong Xu, Xiyun Zhang, Zhanwei Du, Jiarong Xie, Jiu Zhang, Sen Pei, Zijian Feng, Yanqing Hu + + + Matrix-free algorithms for fast ab initio calculations on distributed CPU architectures using finite-element discretization + https://arxiv.org/abs/2512.08571 + arXiv:2512.08571v2 Announce Type: replace +Abstract: Finite-element (FE) discretisations have emerged as a powerful real-space alternative to large-scale Kohn-Sham density functional theory (DFT) calculations, offering systematic convergence, excellent parallel scalability, while accommodating generic boundary conditions. However, the dominant computational bottleneck in FE-based DFT arises from the repeated application of the discretised sparse Hamiltonian to large blocks of trial vectors during iterations in an iterative eigensolver. Traditional sparse matrix-vector multiplications and FE cell-matrix approaches encounter memory limitations and high data-movement overheads, particularly at higher polynomial orders, typically used in DFT calculations. To overcome these challenges, this work develops matrix-free algorithms for FE-discretised DFT that substantially accelerate these products by doing on-the-fly operations that utilize structured tensor contractions over 1D basis functions and quadrature data. A unified multilevel batched data layout that handles both real and complex-valued operators is introduced to maximise cache reuse and SIMD utilisation on Frontier (AVX2), Param Pravega (AVX512) and Fugaku (SVE). We also combine terms for optimal cache reuse, even-odd decomposition to reduce FLOP, and mixed-precision intrinsics. Extensive benchmarks show that for large multivector pseudopotential DFT calculations, the matrix-free kernels deliver 1.5-4x speedups over the state-of-the-art cell-matrix approach baselines. For all-electron DFT calculations, the matrix-free operator achieves gains of up to 5.8x due to its efficient implementation and superior arithmetic intensity. When integrated with an error-tolerant Chebyshev-filtered subspace iteration eigensolver, the matrix-free formalism yields substantial reductions in end-to-end time-to-solution using FE meshes that deliver desired accuracies in ground-state properties. + oai:arXiv.org:2512.08571v2 + physics.comp-ph + Thu, 11 Dec 2025 00:00:00 -0500 + replace + http://creativecommons.org/publicdomain/zero/1.0/ + Gourab Panigrahi, Phani Motamarri + + + PyMieDiff: A differentiable Mie scattering library + https://arxiv.org/abs/2512.08614 + arXiv:2512.08614v2 Announce Type: replace +Abstract: Light scattering by spherical-shaped particles of sizes comparable to the wavelength is foundational in many areas of science, from chemistry to atmospheric science, photonics and nanotechnology. With the new capabilities offered by machine learning, there is a great interest in end-to-end differentiable frameworks for scattering calculations. Here we introduce PyMieDiff, a fully differentiable, GPU-compatible implementation of Mie scattering for core-shell particles in PyTorch. The library provides native, autograd-compatible spherical Bessel and Hankel functions, vectorized evaluation of Mie coefficients, and APIs for computing efficiencies, angular scattering, and near-fields. All inputs - geometry, material dispersion, wavelengths, and observation angles and positions - are represented as tensors, enabling seamless integration with gradient-based optimisation or physics-informed neural networks. The toolkit can also be combined with "TorchGDM" for end-to-end differentiable multi-particle scattering simulations. PyMieDiff is available under an open source licence at https://github.com/UoS-Integrated-Nanophotonics-group/MieDiff. + oai:arXiv.org:2512.08614v2 physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 - replace-cross + physics.comp-ph + Thu, 11 Dec 2025 00:00:00 -0500 + replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - M. E. Kutepov, V. E. Kaydashev, D. V. Stryukov, A. S. Konstantinov, A. V. Nikolskiy, A. T. Kozakov, A. D. Morozov, I. K. Domaratskiy, S. S. Zhukov, E. M. Kaidashev + Oscar K. C. Jackson, Simone De Liberato, Otto L. Muskens, Peter R. Wiecha - Universal criterion for selective outcomes under stochastic resetting - https://arxiv.org/abs/2502.09127 - arXiv:2502.09127v2 Announce Type: replace-cross -Abstract: Resetting plays a pivotal role in optimizing the completion time of complex first passage processes with single or multiple outcomes/exit possibilities. While it is well established that the coefficient of variation -- a statistical dispersion defined as a ratio of the fluctuations over the mean of the first passage time -- must be larger than unity for resetting to be beneficial for any outcome averaged over all the possibilities, the same can not be said while conditioned on a particular outcome. The purpose of this letter is to derive a universal condition which reveals that two statistical metric -- the mean and coefficient of variation of the conditional times -- come together to determine when resetting can expedite the completion of a selective outcome, and furthermore can govern the biasing between preferential and non-preferential outcomes. The universality of this result is demonstrated for a one dimensional diffusion process subjected to resetting with two absorbing boundaries. - oai:arXiv.org:2502.09127v2 - cond-mat.stat-mech - cond-mat.soft - math.PR + Gradient-based optimization of scatterer arrangements based on the T-Matrix method + https://arxiv.org/abs/2512.08615 + arXiv:2512.08615v2 Announce Type: replace +Abstract: The demand for inverse design is increasing as the ability to fabricate sub-10 nm features expands the design space by orders of magnitude. Efficient inverse design benefits from differentiable models of light-structure interaction. While traditional full-wave solvers based on finite differences, finite elements, or Fourier modal methods have already been presented for that purpose, a dedicated tool adapted for performing multiple scattering simulations is still lacking. To overcome this limitation, we provide a multiple-scattering framework compatible to automatic differentiation, suitable for treating periodic and non-periodic arrangements of scatterers. It yields exact gradients regarding geometric and positional parameters in finite clusters and infinite metasurfaces. In this work, we use spheres as the elementary building blocks to demonstrate the framework's capabilities as a standalone tool. However, the framework is adaptable to arbitrarily shaped scatterers, provided the individual T-matrices are calculated using differentiable full-wave Maxwell solvers. Since the gradients are obtained simultaneously in a single backward pass, the framework is well-suited for moderately dimensional problems. It is also possible to combine multiple performance goals into a single objective function. The versatility of our method is illustrated in proof-of-concept examples that focus on various aspects of Kerker-type physics. In the first example, a finite cluster of scatterers is optimized in order to reach a high forward-to-backward scattering ratio, and we show experimental feasibility of the designs. In the second example, a metasurface made from multiple scatterers in each unit cell is designed to maximize the reflectance contrast between orthogonal linear polarizations of the incident light. We make the framework publicly available at https://github.com/tfp-photonics/dreams. + oai:arXiv.org:2512.08615v2 + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 + replace + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Nigar Asadova, Jan David Fischbach, Renaud Vall\'ee, Yannick Augenstein, Dmytro Vovchuk, Anton Kharchevskii, Pavel Ginzburg, Carsten Rockstuhl + + + A simple fourth order propagator based on the Magnus expansion in the Liouville space: Application to a $\Lambda$-system and assessment of the rotating wave approximation + https://arxiv.org/abs/2407.03576 + arXiv:2407.03576v2 Announce Type: replace-cross +Abstract: A simple 4th order propagator [Ture and Jang, {\it J. Phys. Chem. A.} {\bf 128}, 2871 (2024)] based on the Magnus expansion (ME) is extended to the Liouville space for both closed-system and Lindbladian open-system quantum dynamics. For both dynamics, commutator free versions of 4th order propagators are provided as well. These propagators are then applied to the dynamics of a driven $\Lambda$-system, where Lindblad terms represent the effect of a photonic bath. For both dynamics, the accuracy of the rotating wave approximation (RWA) for the matter-radiation interaction is assessed. We confirmed reasonable performance of RWA for weak and resonant fields. However, small errors appear for moderate fields and substantial errors can be found for strong fields where coherent population trapping can still be expected. We also found that the presence of bath for open system quantum dynamics consistently reduces the errors of the RWA. These results provide a quantitative information on how the RWA breaks down beyond weak field or for non-resonant cases. Major results are benchmarked against results of our 6th order ME-based propagator. We also provide numerical comparison of our algorithms with other 4th order algorithms for the $\Lambda$-system. These confirm reasonable performance of out simple propagators and the improvement gained through commutator-free expressions. + oai:arXiv.org:2407.03576v2 + quant-ph + physics.atom-ph physics.chem-ph - Wed, 10 Dec 2025 00:00:00 -0500 + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 replace-cross - http://creativecommons.org/licenses/by/4.0/ - 10.1103/p3yc-kmt1 - Phys. Rev. E 112, 034116, 2025 - Suvam Pal, Leonardo Dagdug, Dibakar Ghosh, Denis Boyer, Arnab Pal + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Taner M. Ture, Changbong Hyeon, Seogjoo J. Jang - Multivariable Behavioral Change Modeling of Epidemics in the Presence of Undetected Infections - https://arxiv.org/abs/2503.00982 - arXiv:2503.00982v3 Announce Type: replace-cross -Abstract: Epidemic models are invaluable tools to understand and implement strategies to control the spread of infectious diseases, as well as to inform public health policies and resource allocation. However, current modeling approaches have limitations that reduce their practical utility, such as the exclusion of human behavioral change in response to the epidemic or ignoring the presence of undetected infectious individuals in the population. These limitations became particularly evident during the COVID-19 pandemic, underscoring the need for more accurate and informative models. To address these challenges, we develop a novel Bayesian epidemic modeling framework to better capture the complexities of disease spread by incorporating behavioral responses and undetected infections. In particular, our framework makes three contributions: 1) leveraging additional data on hospitalizations and deaths in modeling the disease dynamics, 2) accounting for data uncertainty arising from the large presence of asymptomatic and undetected infections, and 3) allowing the population behavioral change to be dynamically influenced by multiple data sources (cases and deaths). We thoroughly investigate the properties of the proposed model via simulation, and illustrate its utility on COVID-19 data from Montreal and Miami. - oai:arXiv.org:2503.00982v3 - stat.ME - physics.soc-ph - Wed, 10 Dec 2025 00:00:00 -0500 + First passage time properties of diffusion with a broad class of stochastic diffusion coefficients + https://arxiv.org/abs/2502.20705 + arXiv:2502.20705v4 Announce Type: replace-cross +Abstract: Diffusion in a heterogeneous environment or diffusion of a particle that shows conformational fluctuations can be described by Brownian motions with stochastic diffusion coefficients (sDCs). In this study, we investigate first passage time (FPT) properties of diffusion with a broad class of non-zero sDCs. We show that for diffusion in one-dimensional semi-infinite domain with an absorbing boundary, particles will eventually reach the boundary with probability one, and that diffusion with a sDC exhibits higher transport efficiency in an early arrival of particles at the boundary than would be expected under diffusion whose DC is the ensemble average (EA) of the sDC. When particles begin to reach an absorbing boundary before the change in a sDC occurs, diffusion with a sDC with a larger supremum exhibits a more efficient transport in an early arrival of particles at the boundary even if the EAs of sDCs are the same. For ergodic DCs, the mean FPT is infinite. In addition, if particles take a long time to reach an absorbing boundary, higher transport efficiency in an early arrival at the boundary almost disappears and the FPT distribution can be approximated by the L\'evy-Smirnov distribution. We show that these three properties result from the convergence of the time average of the DC to the EA and the convergence speed is determined by the time scale of fluctuations in the DC. We finally discuss the similarities and differences of FPT properties between three-dimensional diffusion outside a spherical absorbing boundary and the one-dimensional diffusion. Our results indicate that fluctuations in DCs may need to be non-Markov and/or non-ergodic to allow efficient transport of particles to distant targets. Our results also suggest that fluctuations in a DC play an important role, for example, in diffusion-limited reactions triggered by single molecules in physics, chemistry, or biology. + oai:arXiv.org:2502.20705v4 + cond-mat.stat-mech + physics.bio-ph + Thu, 11 Dec 2025 00:00:00 -0500 replace-cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Caitlin Ward, Rob Deardon, Alexandra M. Schmidt + Go Uchida, Hiromi Miyoshi, Hitoshi Washizu - An empirical formulation of accelerated molecular dynamics for simulating and predicting microstructure evolution in materials - https://arxiv.org/abs/2503.14294 - arXiv:2503.14294v3 Announce Type: replace-cross -Abstract: Despite its widespread use in materials science, conventional molecular dynamics (MD) simulations are severely constrained by timescale limitations. To address this shortcoming, we propose an empirical formulation of accelerated MD method, adapted from a collective-variable-based extended system dynamics framework. While this framework is originally developed for efficient free energy sampling and reaction pathway determination of specific rare events in condensed matter, we have modified it to enable accelerated MD simulation and prediction of microstructure evolution of materials across a broad range of scenarios. In essence, the nearest neighbor off-centering absolute displacement (NNOAD), which quantifies the deviation of an atom from the geometric center of its nearest neighbors in materials, is introduced. We propose that the collection of NNOADs of all atoms can serve as a generalized reaction coordinate for various structural transitions in materials. The NNOAD of each atom, represented by its three components, is coupled with three additional dynamic variables assigned to the atom. Time evolution of the additional dynamic variables follows Langevin equation, while Nos\'e-Hoover dynamics is employed to thermostat the system. Through careful analysis and benchmark simulations, we established appropriate parameter ranges for the equations in our method. Application of this method to several test cases demonstrates its capability to accelerate MD simulations by several orders of magnitude while maintaining kinetic consistency and good accuracy in predicting long timescale microstructure evolutions of materials. We also provide some preliminary thoughts on theoretical justification of the method, offering insights into its underlying principles. - oai:arXiv.org:2503.14294v3 + Pre-training, fine-tuning, and distillation (PFD): Automatically generating machine learning force fields from universal models + https://arxiv.org/abs/2502.20809 + arXiv:2502.20809v3 Announce Type: replace-cross +Abstract: Universal force fields generalizable across the periodic table represent a new trend in computational materials science. However, the applications of universal force fields in material simulations are limited by their slow inference speed and the lack of first-principles accuracy. Instead of building a single model simultaneously satisfying these characteristics, a strategy that quickly generates material-specific models from the universal model may be more feasible. Here, we propose a new workflow pattern, PFD (Pre-training, Fine-tuning, and Distillation), which automatically generates machine-learning force fields for specific materials from a pre-trained universal model through fine-tuning and distillation. By fine-tuning the pre-trained model, our PFD workflow generates force fields with first-principles accuracy while requiring one to two orders of magnitude less training data compared to traditional methods. The inference speed of the generated force field is further improved through distillation, meeting the requirements of large-scale molecular simulations. Comprehensive testing across diverse materials including complex systems, such as amorphous carbon, interface, etc., reveals marked enhancements in training efficiency, which suggests the PFD workflow a practical and reliable approach for force field generation in computational material sciences. + oai:arXiv.org:2502.20809v3 cond-mat.mtrl-sci physics.comp-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 replace-cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Liang Wan, Qingsong Mei, Haowen Liu, Huafeng Zhang, Jun-Ping Du, Shigenobu Ogata, Wen Tong Geng + http://creativecommons.org/licenses/by/4.0/ + 10.1103/sbz6-btz8 + Phys. Rev. Materials (2025) 9, 113802 + Ruoyu Wang, Yuxiang Gao, Hongyu Wu, Zhicheng Zhong - Elucidated Rolling Diffusion Models for Probabilistic Forecasting of Complex Dynamics - https://arxiv.org/abs/2506.20024 - arXiv:2506.20024v3 Announce Type: replace-cross -Abstract: Diffusion models are a powerful tool for probabilistic forecasting, yet most applications in high-dimensional complex systems predict future states individually. This approach struggles to model complex temporal dependencies and fails to explicitly account for the progressive growth of uncertainty inherent to the systems. While rolling diffusion frameworks, which apply increasing noise to forecasts at longer lead times, have been proposed to address this, their integration with state-of-the-art, high-fidelity diffusion techniques remains a significant challenge. We tackle this problem by introducing Elucidated Rolling Diffusion Models (ERDM), the first framework to successfully unify a rolling forecast structure with the principled, performant design of Elucidated Diffusion Models (EDM). To do this, we adapt the core EDM components-its noise schedule, network preconditioning, and Heun sampler-to the rolling forecast setting. The success of this integration is driven by three key contributions: (i) a novel loss weighting scheme that focuses model capacity on the mid-range forecast horizons where determinism gives way to stochasticity; (ii) an efficient initialization strategy using a pre-trained EDM for the initial window; and (iii) a bespoke hybrid sequence architecture for robust spatiotemporal feature extraction under progressive denoising. On 2D Navier-Stokes simulations and ERA5 global weather forecasting at 1.5-degree resolution, ERDM consistently outperforms key diffusion-based baselines, including conditional autoregressive EDM. ERDM offers a flexible and powerful general framework for tackling diffusion-based dynamics forecasting problems where modeling uncertainty propagation is paramount. - oai:arXiv.org:2506.20024v3 - cs.LG - cs.AI - physics.ao-ph - stat.ML - Wed, 10 Dec 2025 00:00:00 -0500 + Initial acquisition requirements for optical cavities in the space gravitational wave antennae DECIGO and B-DECIGO + https://arxiv.org/abs/2503.12960 + arXiv:2503.12960v2 Announce Type: replace-cross +Abstract: DECIGO (DECi-hertz Interferometer Gravitational Wave Observatory) is a space-based gravitational wave antenna concept targeting the 0.1-10 Hz band. It consists of three spacecraft arranged in an equilateral triangle with 1,000 km sides, forming Fabry-P\'erot cavities between them. A precursor mission, B-DECIGO, is also planned, featuring a smaller 100 km triangle. Operating these cavities requires ultra-precise formation flying, where inter-mirror distance and alignment must be precisely controlled. Achieving this necessitates a sequential improvement in precision using various sensors and actuators, from the deployment of the spacecraft to laser link acquisition and ultimately to the control of the Fabry-P\'erot cavities to maintain resonance. In this paper, we derive the precision requirements at each stage and discuss the feasibility of achieving them. We show that the relative speed between cavity mirrors must be controlled at the sub-micrometer-per-second level and that relative alignment must be maintained at the sub-microradian level to obtain control signals from the Fabry-P\'erot cavities of DECIGO and B-DECIGO. + oai:arXiv.org:2503.12960v2 + gr-qc + astro-ph.IM + physics.ins-det + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 replace-cross http://creativecommons.org/licenses/by/4.0/ - Advances in Neural Information Processing Systems (NeurIPS), 2025 - Salva R\"uhling Cachay, Miika Aittala, Karsten Kreis, Noah Brenowitz, Arash Vahdat, Morteza Mardani, Rose Yu + 10.1088/1361-6382/ae1b61 + Classical and Quantum Gravity 42, 225027 (2025) + Yuta Michimura, Koji Nagano, Kentaro Komori, Kiwamu Izumi, Takahiro Ito, Satoshi Ikari, Tomotada Akutsu, Masaki Ando, Isao Kawano, Mitsuru Musha, Shuichi Sato - A molecule with half-M\"obius topology - https://arxiv.org/abs/2507.03516 - arXiv:2507.03516v2 Announce Type: replace-cross -Abstract: Stereoisomers of C$_{13}$Cl$_2$ exhibiting helical orbitals around a ring of carbon atoms were synthesized by atom manipulation on NaCl surfaces. We resolved the enantiomeric geometries of the closed-shell singlet states by atomic force microscopy and mapped their helical orbital densities by scanning tunnelling microscopy. A ${\pi}$-orbital basis of the helical, non-planar singlets that twists by 90{\deg} in one circulation is consistent with a half-M\"obius topology. In such a topology, the ${\pi}$-orbital basis changes sign with respect to two circumnavigations and is periodic with respect to four circumnavigations. A quasiparticle on a ring with this boundary condition could be interpreted as carrying a Berry phase of ${\pi}$/2. We demonstrate reversible switching of the topology, between the two singlets of oppositely threaded half-M\"obius topology, and the planar, topologically trivial, triplet state. Multireference calculations, including large-scale sample-based ab initio calculations executed on quantum hardware, reveal that the switching is associated with a helical pseudo Jahn-Teller effect. - oai:arXiv.org:2507.03516v2 - cond-mat.mes-hall - physics.chem-ph - Wed, 10 Dec 2025 00:00:00 -0500 + The Role of Planetary-Scale Waves on the Stratospheric Superrotation in Titan's Atmosphere + https://arxiv.org/abs/2503.15728 + arXiv:2503.15728v2 Announce Type: replace-cross +Abstract: We analyze simulation results from the TitanWRF global circulation model to understand the mechanisms that maintain the equatorial superrotation in Titan's stratosphere. We find that the eddies associated with wave activities can transport angular momentum upgradient to zonal flow, leading to acceleration of the equatorial superrotation. The dominant wave modes identified in this study are consistent with previous studies, with zonal wavenumber 1 being the major contributor to the prograde acceleration. Despite the same conclusion of maintenance of equatorial superrotation via wave-mean interactions, we find that the way waves interact with the zonal flow in TitanWRF is slightly different from some other studies. We confirm our previous findings that in TitanWRF this occurs primarily during a dozen or so annual, short-duration (a few Titan sols) angular momentum "transfer events", which have a repeatable seasonal pattern but differ slightly in timing and magnitude between years. This is not the case in the Titan Atmosphere Model (TAM), which found milder angular momentum transfers that produced the strongest acceleration of superrotation around solstice in the upper stratosphere and more continuous year-around acceleration in the lower stratosphere. Despite differences in angular momentum transfer across models, we further find that, similar to the TAM wave analysis results, eddies generated by Rossby-Kelvin instabilities may be the major source of prograde angular momentum for the equatorial superrotation, although TitanWRF may also include contributions from the absorption of vertically propagating equatorial Kelvin waves. This differs from our previous work, which suggested barotropic waves were responsible for TitanWRF's solsticial transfer event. + oai:arXiv.org:2503.15728v2 + astro-ph.EP + physics.ao-ph + Thu, 11 Dec 2025 00:00:00 -0500 replace-cross http://creativecommons.org/licenses/by/4.0/ - Igor Roncevic, Fabian Paschke, Yueze Gao, Leonard-Alexander Lieske, Lene A. G\"odde, Stefano Barison, Samuele Piccinelli, Alberto Baiardi, Ivano Tavernelli, Jascha Repp, Florian Albrecht, Harry L. Anderson, Leo Gross + Yuan Lian, Cecilia Leung, Claire Newman, Leslie Tamppari - Thermochemical models of outer core convection with heterogeneous core-mantle boundary heat flux - https://arxiv.org/abs/2507.03538 - arXiv:2507.03538v2 Announce Type: replace-cross -Abstract: Thermochemical convection in Earth's outer core is driven by the crystallisation of the inner core that releases latent heat and light elements. A key question in core dynamics is whether a stable layer exists just below the core-mantle boundary. Recent core convection simulations, accounting for CMB heterogeneities, propose locally stable regions (or regional inversion lenses, RILs) rather than a global layer, allowing both stable and unstable regions to coexist. In this study, we consider a suite of numerical simulations of thermal, chemical, and thermochemical convection models focussed on Ekman number ($E=10^{-5}$) with thermal and chemical flux Rayleigh numbers $\widetilde{Ra}_T=30-4000$ and $\widetilde{Ra}_C=30-100000$, and thermal and chemical Prandtl numbers $Pr_T=1$ and $Pr_\xi=10$. Analysis of purely chemical models reveals light element accumulation (LEA) below the CMB, resulting in either locally stable regions near the poles or global layers, depending on the strength of chemical forcing. These chemically stratified regions persist in our thermochemical models even if the thermal field is fully destabilising. The addition of a heterogeneous CMB heat flux leads to the formation of RILs driven by thermal stratification. Stable regions in these thermochemical models have varying locations, properties, and morphologies depending on whether thermal or chemical convection dominates. In the investigated parameter range, these RILs are O(100 km) thick, and their strength and thickness generally increase with the strength of thermal driving; they are comparatively less sensitive to the strength of chemical driving. Our simulations reveal a diverse range of possible stable regions and/or a global layer at the top of Earth's core, with a seismically plausible range of thickness and strength, which may also have a signature in geomagnetic observations. - oai:arXiv.org:2507.03538v2 - astro-ph.EP - physics.geo-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Accurate Prediction of Tensorial Spectra Using Equivariant Graph Neural Network + https://arxiv.org/abs/2505.04862 + arXiv:2505.04862v4 Announce Type: replace-cross +Abstract: Optical spectroscopies provide a powerful tool for harnessing light-matter interactions for unraveling complex electronic features such as the flat bands and nontrivial topologies of materials. These insights are crucial for the development and optimization of optoelectronic devices, including solar cells, light-emitting diodes, and photodetectors, where device performance is closely connected with the nature of the underlying electronic spectrum. Realistic modeling of tensor optical responses in materials, which are computationally quite demanding, however, remains challenging. Here we introduce the Tensorial Spectra Equivariant Neural Network (TSENN), which is a equivariant graph neural network architecture that maps crystal structures directly to their full photon-frequency-dependent optical tensors. By encoding the isotropic sequential scalar components along with the anisotropic sequential tensor components into l = 0 and l = 2 spherical tensor components, TSENN ensures symmetry-aware predictions that are consistent with the constraints of crystalline symmetries of materials. Trained on a dataset of frequency-dependent permittivity tensors of 1,432 bulk semiconductors computed using first-principles methods, our model achieves a mean absolute error (MAE) of 21.181 millifarads per meter (mF/m), demonstrating its potential for efficient modeling of other related properties such as the optical conductivities. Our framework opens new avenues for rational data-driven design of anisotropic optical responses for accelerating materials discovery for advancing optoelectronic applications. + oai:arXiv.org:2505.04862v4 + cond-mat.mtrl-sci + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 replace-cross http://creativecommons.org/licenses/by/4.0/ - Souvik Naskar, Jonathan E. Mound, Christopher J. Davies, Andrew T. Clarke + Ting-Wei Hsu, Zhenyao Fang, Arun Bansil, Qimin Yan - PET Image Reconstruction Using Deep Diffusion Image Prior - https://arxiv.org/abs/2507.15078 - arXiv:2507.15078v2 Announce Type: replace-cross -Abstract: Diffusion models have shown great promise in medical image denoising and reconstruction, but their application to Positron Emission Tomography (PET) imaging remains limited by tracer-specific contrast variability and high computational demands. In this work, we proposed an anatomical prior-guided PET image reconstruction method based on diffusion models, inspired by the deep diffusion image prior (DDIP) framework. The proposed method alternated between diffusion sampling and model fine-tuning guided by the PET sinogram, enabling the reconstruction of high-quality images from various PET tracers using a score function pretrained on a dataset of another tracer. To improve computational efficiency, the half-quadratic splitting (HQS) algorithm was adopted to decouple network optimization from iterative PET reconstruction. The proposed method was evaluated using one simulation and two clinical datasets. For the simulation study, a model pretrained on [$^{18}$F]FDG data was tested on [$^{18}$F]FDG data and amyloid-negative PET data to assess out-of-distribution (OOD) performance. For the clinical-data validation, ten low-dose [$^{18}$F]FDG datasets and one [$^{18}$F]Florbetapir dataset were tested on a model pretrained on data from another tracer. Experiment results show that the proposed PET reconstruction method can generalize robustly across tracer distributions and scanner types, providing an efficient and versatile reconstruction framework for low-dose PET imaging. - oai:arXiv.org:2507.15078v2 - eess.IV - cs.CV - physics.med-ph - Wed, 10 Dec 2025 00:00:00 -0500 + A parametric tensor ROM for the shallow water dam break problem + https://arxiv.org/abs/2506.20007 + arXiv:2506.20007v2 Announce Type: replace-cross +Abstract: We develop a variant of a tensor reduced-order model (tROM) for the parameterized shallow-water dam-break problem. This hyperbolic system presents multiple challenges for model reduction, including a slow decay of the Kolmogorov $N$-width of the solution manifold, shock formation, and the loss of smooth solution dependence on parameters. These issues limit the performance of traditional Proper Orthogonal Decomposition based ROMs. Our tROM approach, based on a low-rank tensor decomposition, builds a parameter-to-solution map from high-fidelity snapshots and constructs localized reduced bases via a local POD procedure. We apply this method to 1D dry-bed and wet-bed problems and 2D wet-bed problem with topography and bottom friction, showing that the non-interpolatory variant of the tROM, combined with Chebyshev sampling near critical parameter values, effectively captures parameter-dependent behavior and significantly outperforms standard POD-ROMs. This is especially evident in the wet-bed case, where POD-ROMs exhibit poor resolution of shock waves and spurious oscillations. + oai:arXiv.org:2506.20007v2 + math.NA + cs.NA + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 replace-cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Fumio Hashimoto, Kuang Gong + http://creativecommons.org/licenses/by-sa/4.0/ + Md Rezwan Bin Mizan, Maxim Olshanskii, Ilya Timofeyev - Physical Constraints on the Rhythmicity of the Biological Clock - https://arxiv.org/abs/2507.20750 - arXiv:2507.20750v2 Announce Type: replace-cross -Abstract: Circadian rhythms in living organisms are temporal orders emerging from biochemical circuits driven out of equilibrium. Here, we study how the rhythmicity of KaiABC clock is generated from the underlying circuit. The phase diagram in terms of KaiC and KaiA concentrations reveals a narrowly bounded oscillatory phase. As dictated by the cost-precision trade-offs of the thermodynamic uncertainty relations, the presence of intrinsic noise, amplified in small systems, demands higher energy cost to achieve greater rhythmic precision. The cost-minimizing condition giving rise to $\sim$21-hr rhythm is identified close enough to entrain the system to 24-hr environmental signals. An optimal level of intrinsic noise can induce oscillations beyond the Hopf bifurcation, effectively expanding the oscillatory phase. Our study clarifies how the physical factors, such as energy cost, stochastic noise, and regulatory mechanism, contribute to the operation of biological clocks. - oai:arXiv.org:2507.20750v2 - cond-mat.stat-mech + Quantifying Ocular Surface Changes with Contact Lens Wear + https://arxiv.org/abs/2507.13589 + arXiv:2507.13589v2 Announce Type: replace-cross +Abstract: Over 140 million people worldwide and over 45 million people in the United States wear contact lenses; it is estimated that 12%-27.4% contact lens users stop wearing them due to discomfort. Contact lens mechanical interactions with the ocular surface have been found to affect the ocular surface itself. These mechanical interactions are difficult to measure and calculate in a clinical setting, and the research in this field is limited. This paper presents the first mathematical model that captures the interactions between the contact lens and the open eye, where the contact lens configuration, the contact lens suction pressure, and the deformed ocular shape are all emergent properties of the model. The non-linear coupling between the contact lens and the eye is achieved by assuming that the suction pressure under the lens is applied directly to the ocular surface through the post-lens tear film layer. The contact lens mechanics are modeled using a previous published model. We consider homogeneous and heterogeneous linear elastic eye models, different ocular shapes, different lens shapes and thickness profiles, and extract lens deformations, suction pressure profiles, and ocular deformations and stresses for all the considered scenarios. The model predicts higher ocular deformations and stresses at the center of the eye and in the limbal/scleral regions. Accounting for heterogeneous material eye parameters increases the magnitude of such deformations and stresses. The ocular displacements and stresses non-linearly increase as we increase the stiffness of the contact lens. Inserting a steeper contact lens on the eye results in a reduction of the ocular displacement at the center of the eye and a larger displacement at the edge of the contact lens. The model predictions are compared with experimental data and previously developed mathematical models. + oai:arXiv.org:2507.13589v2 + math.NA + cs.NA physics.bio-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 replace-cross - http://creativecommons.org/licenses/by/4.0/ - YeongKyu Lee, Changbong Hyeon + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + 10.3934/mbe.2026008 + Mathematical Biosciences and Engineering (2026), Volume 23, Issue 1: 172-209 + Lucia Carichino, Kara L. Maki, David S. Ross, Riley K. Supple, Evan Rysdam - A Non-Local Orientation Field Phase-Field Model for Misorientation- and Inclination- Dependent Grain Boundaries - https://arxiv.org/abs/2508.01688 - arXiv:2508.01688v3 Announce Type: replace-cross -Abstract: We propose to incorporate grain boundary (GB) anisotropy in phase-field modeling by extending the standard partial differential equations formulation to include a non-local functional of an orientation field. Regardless of the number of grains in the simulation, the model uses a single orientation field and incorporates grain misorientation and inclination information obtained from sampling the orientation field at optimized locations in the vicinity of the grain boundary. The formalism enables simple and precise tuning of GB energy anisotropy while avoiding an extensive fitting procedure. The functional includes an explicit GB anisotropy function to control the GB energy as a function of both misorientation and inclination. The model is validated by reproducing the linear grain growth rate, Wulff shapes with varying misorientations and anisotropic coefficients, and analytical equilibrium dihedral angles at triple junctions. Polycrystalline simulations demonstrate grain growth, coalescence, triple junction behavior, and the influence of anisotropy on grain morphology. - oai:arXiv.org:2508.01688v3 + Minimising the Demand for High-Fidelity Training Data towards Chemically Accurate Adsorption Energy Predictions + https://arxiv.org/abs/2507.20496 + arXiv:2507.20496v2 Announce Type: replace-cross +Abstract: Adsorption energy is a critical descriptor for high-throughput screening of heterogeneous catalysts and electrode materials. However, precise experimental data are scarce due to the complexity of experiments, while high-fidelity density functional theory (DFT) calculations remain computationally expensive for large-scale material screening. Machine learning models trained on DFT data have emerged as a promising alternative but face challenges such as functional dependency and limited high-fidelity labelled data. Herein, we present DOS Transformer for Adsorption (DOTA), a functional-independent deep learning model established on the map between local density of states (LDOS) and adsorption energy. DOTA integrates multi-head self-attention mechanisms with LDOS feature engineering to capture latent orbital interaction patterns, enabling it to unify multi-fidelity and multi-source data. This minimises the demand for high-fidelity training data. Consequently, the predictive adsorption energy could reach chemical accuracy, requiring less than five high-fidelity experimental adsorption energies for model training. DOTA also resolves long-standing challenges, such as the "CO puzzle", and outperforms traditional theories, including the d-band centre and Fermi softness models. It provides a robust framework for efficient catalyst and electrode screening, bridging the gap between computational and experimental data. + oai:arXiv.org:2507.20496v2 + cond-mat.dis-nn cond-mat.mtrl-sci + physics.chem-ph + Thu, 11 Dec 2025 00:00:00 -0500 + replace-cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Zhihao Zhang, Xiao-Ming Cao + + + Adjoint path-kernel method for backpropagation and data assimilation in unstable diffusions + https://arxiv.org/abs/2507.21497 + arXiv:2507.21497v2 Announce Type: replace-cross +Abstract: We derive the adjoint path-kernel method for computing parameter-gradients (linear responses) of SDEs. Its cost is almost independent of the number of parameters, and it works for non-hyperbolic systems with parameter-controlled multiplicative noise. With this new formula, we extend the conventional backpropagation method to settings with gradient explosion, and demonstrate it on the 40-dimensional Lorenz 96 system. + Moreover, we consider a difficult version of the 4D-Var data assimilation problem where (1) the deterministic part of the model is chaotic, (2) the loss is a single long-time functional accounting for discrepancies in both the observations and the dynamics, (3) some parameters in the dynamics are unknown, and (4) some coordinates of the states cannot be observed, and cannot be reasonably inferred from other coordinates within a short time. We model the correction term at each time-step separately as a parameterized function of the random state. With our new tool, we can run stochastic gradient descent to find the path and parameters that best match the low-dimensional observation data. We demonstrate this on the 10D Lorenz-96 system with 8D observations. + oai:arXiv.org:2507.21497v2 + math.PR + math.DS physics.comp-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 replace-cross - http://creativecommons.org/licenses/by/4.0/ - Xiao Han, Axel van de Walle + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Angxiu Ni - Random-phase Wave Splatting of Translucent Primitives for Computer-generated Holography - https://arxiv.org/abs/2508.17480 - arXiv:2508.17480v2 Announce Type: replace-cross -Abstract: Holographic near-eye displays offer ultra-compact form factors for VR/AR systems but rely on advanced computer-generated holography (CGH) algorithms to convert 3D scenes into interference patterns on spatial light modulators (SLMs). Conventional CGH typically generates smooth-phase holograms, limiting view-dependent effects and realistic defocus blur, while severely under-utilizing the SLM space-bandwidth product. - We propose Random-phase Wave Splatting (RPWS), a unified wave optics rendering framework that converts arbitrary 3D representations based on 2D translucent primitives into random-phase holograms. RPWS is fully compatible with modern 3D representations such as Gaussians and triangles, improves bandwidth utilization which effectively enlarges eyebox size, reconstructs accurate defocus blur and parallax, and leverages time-multiplexed rendering not as a heuristic for speckle suppression, but as a mathematically exact alpha-blending mechanism derived from first principles in statistics. At the core of RPWS are (1) a new wavefront compositing procedure and (2) an alpha-blending scheme for random-phase geometric primitives, ensuring correct color reconstruction and robust occlusion when compositing millions of primitives. - RPWS departs substantially from the recent primitive-based CGH algorithm, Gaussian Wave Splatting (GWS). Because GWS uses smooth-phase primitives, it struggles to capture view-dependent effects and realistic defocus blur and under-utilizes the SLM space-bandwidth product; moreover, naively extending GWS to random-phase primitives fails to reconstruct accurate colors. In contrast, RPWS is designed from the ground up for arbitrary random-phase translucent primitives, and through simulations and experimental validations we demonstrate state-of-the-art image quality and perceptually faithful 3D holograms for next-generation near-eye displays. - oai:arXiv.org:2508.17480v2 - cs.GR - cs.AR - eess.IV - eess.SP + Quantum coherence and negative quasi probabilities in a contextual three-path interferometer + https://arxiv.org/abs/2507.22323 + arXiv:2507.22323v2 Announce Type: replace-cross +Abstract: Basic quantum effects are often illustrated using single particle interferences in two-path interferometers. A wider range of non-classical phenomena can be illustrated using three-path interferometers, but the increased complexity of quantum statistics in a three-dimensional Hilbert space makes it difficult to identify a representative set of observable properties that could be used to characterize specific phenomena. Here, I propose a characterization of pure states based on a five-stage interferometer recently introduced to demonstrate the relation between different measurement contexts (Optica Quantum 1, 63 (2023)). It is shown that the orthogonality relations between the states representing the different measurement contexts can be used to classify pure states within the three-dimensional Hilbert space according to the non-classical correlations between different contexts expressed by negative Kirkwood-Dirac distributions. + oai:arXiv.org:2507.22323v2 + quant-ph physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 + replace-cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Holger F. Hofmann + + + Time as a Cosmological Phenomenon + https://arxiv.org/abs/2508.01803 + arXiv:2508.01803v3 Announce Type: replace-cross +Abstract: We show that the arrow of time is intimately related to the geometry and topology of the whole universe, and is therefore best understood as a cosmological phenomenon. + oai:arXiv.org:2508.01803v3 + gr-qc + physics.hist-ph + Thu, 11 Dec 2025 00:00:00 -0500 replace-cross http://creativecommons.org/licenses/by/4.0/ - Brian Chao, Jacqueline Yang, Suyeon Choi, Manu Gopakumar, Ryota Koiso, Gordon Wetzstein + Andrea Palessandro - Quantization of the electromagnetic fields from single atomic or molecular radiators - https://arxiv.org/abs/2509.07359 - arXiv:2509.07359v3 Announce Type: replace-cross -Abstract: A framework is introduced for expressing electromagnetic (EM) potentials and fields of single atomic or molecular emitters modeled as oscillating dipoles, which follows a recently proposed method for solving inhomogeneous wave equations for arbitrary, time-dependent distributions of charge. This framework is first used to evaluate the physical implications of simplifying assumptions made in the standard approach to quantization of the EM fields and the impact of such assumptions on the results of energy and momentum quantization. Then, the exact expressions for the EM potentials and fields, in relation to the oscillating (transition) dipoles properties, afforded by the present framework are used to quantize electromagnetic fields from single emitters and restore the agreement with the well-known classical dipole radiation pattern, while maintaining the quantum mechanical description of electromagnetic radiation in terms of the probability distribution of quantum modes. Contributions of the present analysis to the understanding of photon emission from excited atoms or molecules stimulated by light or vacuum field fluctuations are highlighted, and possible experimental tests and practical applications are proposed. - oai:arXiv.org:2509.07359v3 + Stoquasticity is not enough: towards a sharper diagnostic for Quantum Monte Carlo simulability + https://arxiv.org/abs/2508.14382 + arXiv:2508.14382v2 Announce Type: replace-cross +Abstract: Quantum Monte Carlo (QMC) methods are powerful tools for simulating quantum many-body systems, yet their applicability is limited by the infamous sign problem. We approach this challenge through the lens of Vanishing Geometric Phases (VGP) \cite{Hen_2021}, introducing it as a `geometric' criterion for diagnosing QMC simulability. We characterize the class of VGP Hamiltonians, and analyze the complexity of recognizing this class, identifying both hard and efficiently identifiable cases. We further highlight the practical advantage of the VGP criterion by exhibiting specific Hamiltonians that are readily identified as sign-problem-free through VGP, yet whose stoquasticity is difficult to ascertain. These examples underscore the efficiency and sharpness of VGP as a diagnostic tool compared to stoquasticity-based heuristics. Beyond classification, we propose a family of VGP-inspired diagnostics that serve as quantitative indicators of sign problem severity. While exact evaluation of these quantities is generically intractable, we demonstrate their mathematical power in performing scaling analysis for the average sign under unitary transformations. Our results provide both a conceptual foundation and practical tools for understanding and mitigating the sign problem. + oai:arXiv.org:2508.14382v2 quant-ph - physics.class-ph - physics.optics - Wed, 10 Dec 2025 00:00:00 -0500 + cond-mat.stat-mech + physics.comp-ph + Thu, 11 Dec 2025 00:00:00 -0500 replace-cross - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Valerica Raicu + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Arman Babakhani, Armen Karakashian - Dynamics of Ideal Fluid Flows - https://arxiv.org/abs/2511.16254 - arXiv:2511.16254v2 Announce Type: replace-cross -Abstract: We will discuss various aspects of the incompressible Euler equation. We will discuss, in particular, problems related to the least action principle, the existence of special solutions, the problem of solvability, singularity formation, and asymptotic behavior. - oai:arXiv.org:2511.16254v2 - math.AP - physics.flu-dyn - Wed, 10 Dec 2025 00:00:00 -0500 + Metastable phase separation and information retrieval in multicomponent mixtures + https://arxiv.org/abs/2509.10705 + arXiv:2509.10705v2 Announce Type: replace-cross +Abstract: Liquid mixtures can separate into phases with distinct composition. This phenomenon has recently come back to prominence due to its role in complex biological liquids, such as the cytoplasm, which contain thousands of components. For simple two-component mixtures phase-separated states are global free energy minima. However, local free energy minima, i.e. metastable states, are known to play a dominant role in complex systems with many components. For example, Hopfield neural networks can retrieve information from partial cues via relaxation to metastable states. Under what conditions can phase separated states be metastable, and what are the implications for information processing in multicomponent liquids? In this work we develop the general thermodynamic formalism of metastable phase separation. We then apply this formalism to an illustrative toy example inspired by recent experiments, binary mixtures with high-order interactions. Finally, as core application of the formalism, we study metastability in Hopfield liquids, a class of multicomponent mixtures capable of storing information on the composition of phases. We show that these phases can be retrieved from partial cues via metastable phase separation. Spatial simulations of liquids with a large number of components match our analytical solution. Our work suggests that complex biological mixtures can perform information retrieval through metastable phase separation. + oai:arXiv.org:2509.10705v2 + cond-mat.stat-mech + cond-mat.dis-nn + cond-mat.soft + physics.bio-ph + Thu, 11 Dec 2025 00:00:00 -0500 replace-cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Tarek M. Elgindi + Rodrigo Braz Teixeira, Izaak Neri, Pablo Sartori - The Albedo Problem and Cloud Cover on Hot Jupiters - https://arxiv.org/abs/2511.18497 - arXiv:2511.18497v2 Announce Type: replace-cross -Abstract: Observations of transiting hot Jupiters have revealed a mismatch between the values of the Bond versus geometric albedos. In the planetary science literature, the ratio of these quantities is known as the phase integral. It has been extensively measured for the Solar System planets and shown to generally be non-unity in value. We use existing Cassini data of Jupiter to derive bandpass-integrated geometric albedos and phase integrals in the CHEOPS, TESS and Ariel bandpasses, demonstrating that these quantities vary markedly across these different wavelength ranges. By performing a population study of geometric albedos and phase integrals, we demonstrate that atmospheres with partial cloud cover may be identified using measurements of the phase integral if its measured uncertainty is $\sim 0.1$, which corresponds to an uncertainty of $\sim 3\%$ on the optical/visible secondary eclipse depth. The upcoming Ariel space mission will conduct an unprecedented statistical survey of cloud cover on hot Jupiters via the simultaneous measurement of $\sim 100$ infrared phase curves and optical secondary eclipses. Whenever available, the shape of optical phase curves of reflected light will directly constrain the phase integral, spherical albedo, degree of cloud cover and scattering asymmetry factor. - oai:arXiv.org:2511.18497v2 - astro-ph.EP - physics.ao-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Bayesian power spectral density estimation for LISA noise based on P-splines with a parametric boost + https://arxiv.org/abs/2510.00533 + arXiv:2510.00533v2 Announce Type: replace-cross +Abstract: Flexible and accurate noise characterization is crucial for the precise estimation of gravitational-wave parameters. We introduce a Bayesian method for estimating the power spectral density (PSD) of long, stationary time series, explicitly tailored for LISA data analysis. Our approach models the PSD as the geometric mean of a parametric and a nonparametric component, combining the knowledge from parametric models with the flexibility to capture deviations from theoretical expectations. The nonparametric component is expressed by a mixture of penalized B-splines. Adaptive, data-driven knot placement, performed once at initialization, removes the need for reversible-jump Markov chain Monte Carlo, while hierarchical roughness-penalty priors prevent overfitting. Validation on simulated autoregressive AR(4) data demonstrates estimator consistency and shows that well-matched parametric components reduce the integrated absolute error compared to an uninformative baseline, requiring fewer spline knots to achieve comparable accuracy. Applied to one year of simulated LISA X-channel (univariate) noise, our method achieves relative integrated absolute errors of $\mathcal{O}(10^{-2})$, making it suitable for iterative analysis pipelines and multi-year mission data sets. + oai:arXiv.org:2510.00533v2 + gr-qc + astro-ph.IM + physics.comp-ph + stat.CO + Thu, 11 Dec 2025 00:00:00 -0500 replace-cross - http://creativecommons.org/licenses/by/4.0/ - Kevin Heng, Billy Edwards, Nicolas B. Cowan + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Nazeela Aimen, Patricio Maturana-Russel, Avi Vajpeyi, Nelson Christensen, Renate Meyer - Onsager Condensation in Chiral Active Matter: Universality of Supersonic Topological Gas Dynamics - https://arxiv.org/abs/2512.01884 - arXiv:2512.01884v5 Announce Type: replace-cross -Abstract: To explain how dissipative active turbulence sustains inertial cascades, we construct a chiral model mapping overdamped agents to supersonic topological gas dynamics. Here, Mach cones function as acoustic horizons, shielding defect cores from the sound radiation of shallow water flows. We show that disorder activates a topological heat pump driving an inverse cascade toward a negative-temperature Onsager dipole, unless arrested into a vortex glass by insufficient dispersion. This mapping identifies a universality class unifying active swarms with the statistical mechanics of classical inviscid fluids. - oai:arXiv.org:2512.01884v5 - cond-mat.soft - cond-mat.stat-mech - physics.flu-dyn - Wed, 10 Dec 2025 00:00:00 -0500 + Diffraction by Circular and Triangular Apertures as a Diagnostic Tool of Twisted Matter Waves + https://arxiv.org/abs/2510.00826 + arXiv:2510.00826v3 Announce Type: replace-cross +Abstract: We study diffraction of twisted matter waves (electrons and light ions carrying orbital angular momentum $\ell/\hbar=0,\pm1,\pm2,\ldots$ by circular and triangular apertures. Within the scalar Kirchhoff-Fresnel framework, circular apertures preserve cylindrical symmetry and produce ringlike far-field profiles whose radii and widths depend on $|\ell|$ but are insensitive to its sign. In contrast, equilateral triangles break axial symmetry and yield structured patterns that encode both the magnitude and the sign of $\ell$. A transparent Fraunhofer mapping links detector coordinates to the Fourier plane, explaining the $(|\ell|+1)$-lobe rule and the sign-dependent rotation of the pattern. We validate these results for both ideal Bessel beams and localized Laguerre-Gaussian packets, and we cross-check them by split-step Fourier propagation of the time-dependent Schr"odinger equation. From these analyses we extract practical design rules (Fraunhofer distance, lattice pitch, detector sampling) relevant to OAM diagnostics with moderately relativistic electrons with $E_{\rm kin}\sim0.1$ to $5$ MeV and light ions with $E_{\rm kin}\sim0.1$ to $1$ MeV/u. Our results establish triangular diffraction as a simple, passive, and robust method for reading out the OAM content of structured quantum beams. + oai:arXiv.org:2510.00826v3 + quant-ph + hep-ph + physics.acc-ph + Thu, 11 Dec 2025 00:00:00 -0500 replace-cross - http://creativecommons.org/licenses/by-nc-sa/4.0/ - Magnus F Ivarsen + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + 10.1103/z2rs-2ryl + Maksim Maksimov, Nikita Borodin, Daria Kargina, Dmitry Naumov, Dmitry Karlovets - China Regional 3km Downscaling Based on Residual Corrective Diffusion Model - https://arxiv.org/abs/2512.05377 - arXiv:2512.05377v2 Announce Type: replace-cross -Abstract: A fundamental challenge in numerical weather prediction is to efficiently produce high-resolution forecasts. A common solution is applying downscaling methods, which include dynamical downscaling and statistical downscaling, to the outputs of global models. This work focuses on statistical downscaling, which establishes statistical relationships between low-resolution and high-resolution historical data using statistical models. Deep learning has emerged as a powerful tool for this task, giving rise to various high-performance super-resolution models, which can be directly applied for downscaling, such as diffusion models and Generative Adversarial Networks. This work relies on a diffusion-based downscaling framework named CorrDiff. In contrast to the original work of CorrDiff, the region considered in this work is nearly 40 times larger, and we not only consider surface variables as in the original work, but also encounter high-level variables (six pressure levels) as target downscaling variables. In addition, a global residual connection is added to improve accuracy. In order to generate the 3km forecasts for the China region, we apply our trained models to the 25km global grid forecasts of CMA-GFS, an operational global model of the China Meteorological Administration (CMA), and SFF, a data-driven deep learning-based weather model developed from Spherical Fourier Neural Operators (SFNO). CMA-MESO, a high-resolution regional model, is chosen as the baseline model. The experimental results demonstrate that the forecasts downscaled by our method generally outperform the direct forecasts of CMA-MESO in terms of MAE for the target variables. Our forecasts of radar composite reflectivity show that CorrDiff, as a generative model, can generate fine-scale details that lead to more realistic predictions compared to the corresponding deterministic regression models. - oai:arXiv.org:2512.05377v2 - cs.LG - cs.AI - physics.ao-ph - Wed, 10 Dec 2025 00:00:00 -0500 + exa-AMD: An Exascale-Ready Framework for Accelerating the Discovery and Design of Functional Materials + https://arxiv.org/abs/2510.01170 + arXiv:2510.01170v2 Announce Type: replace-cross +Abstract: We present exa-AMD, an open-source, high-performance framework designed for accelerated materials discovery on modern supercomputers. exa-AMD overcomes key computational bottlenecks in large-scale structure prediction through task-based parallelization, adaptive load balancing, and optimized data management for CPU and GPU architectures. The framework automates the end-to-end workflow, from generating candidate structures to evaluating formation energies and updating phase diagrams. Its modular design allows users to easily replace or extend components with custom machine learning models, alternative initial structure templates, and future structure generators, enabling flexible integration with emerging AI approaches. We demonstrate strong scaling across high-performance computing platforms and highlight applications to Na-B-C, Ce-Co-B, and Fe-Co-Zr systems, establishing exa-AMD as a robust and exascale-ready tool for accelerating the discovery and design of functional materials. exa-AMD is publicly available on GitHub, with detailed documentation and reproducible test cases to support community engagement and collaborative research. + oai:arXiv.org:2510.01170v2 + cond-mat.mtrl-sci + physics.comp-ph + Thu, 11 Dec 2025 00:00:00 -0500 replace-cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Honglu Sun, Hao Jing, Zhixiang Dai, Sa Xiao, Wei Xue, Jian Sun, Qifeng Lu + http://creativecommons.org/licenses/by-nc-sa/4.0/ + Weiyi Xia, Maxim Moraru, Ying Wai Li, Cai-Zhuang Wang - Towards agent-based-model informed neural networks - https://arxiv.org/abs/2512.05764 - arXiv:2512.05764v2 Announce Type: replace-cross -Abstract: In this article, we present a framework for designing neural networks that remain consistent with the underlying principles of agent-based models. We begin by highlighting the limitations of standard neural differential equations in modeling complex systems, where physical invariants (like energy) are often absent but other constraints (like mass conservation, information locality, bounded rationality) must be enforced. To address this, we introduce Agent-Based-Model informed Neural Networks (ABM-NNs), which leverage restricted graph neural networks and hierarchical decomposition to learn interpretable, structure-preserving dynamics. We validate the framework across three case studies of increasing complexity: (i) a generalized Generalized Lotka--Volterra system, where we recover ground-truth parameters from short trajectories in presence of interventions; (ii) a graph-based SIR contagion model, where our method outperforms state-of-the-art graph learning baselines (GCN, GraphSAGE, Graph Transformer) in out-of-sample forecasting and noise robustness; and (iii) a real-world macroeconomic model of the ten largest economies, where we learn coupled GDP dynamics from empirical data and demonstrate counterfactual analysis for policy interventions - oai:arXiv.org:2512.05764v2 - cs.LG - cs.SI + Phase locking and multistability in the topological Kuramoto model on cell complexes + https://arxiv.org/abs/2510.05831 + arXiv:2510.05831v2 Announce Type: replace-cross +Abstract: The topological Kuramoto model generalizes classical synchronization models by including higher-order interactions, with oscillator dynamics defined on cells of arbitrary dimension within simplicial or cell complexes. In this article, we demonstrate multistability in the topological Kuramoto model and develop the topological nonlinear Kirchhoff conditions algorithm to identify all phase-locked states on arbitrary cell complexes. The algorithm is based on a generalization of Kirchhoff's laws to cell complexes of arbitrary dimension and nonlinear interactions between cells. By applying this framework to rings, Platonic solids, and simplexes, as minimal representative motifs of larger networks, we derive explicit bounds (based on winding number constraints) that determine the number of coexisting stable states. We uncover structural cascades of multistability, inherited from both lower and higher dimensions and demonstrate that cell complexes can generate richer multistability patterns than simplicial complexes of the same dimension. Moreover, we find that multistability patterns in cell complexes appear to be determined by the number of boundary cells, hinting a possible universal pattern. + oai:arXiv.org:2510.05831v2 nlin.AO + math.DS + nlin.CD physics.soc-ph - Wed, 10 Dec 2025 00:00:00 -0500 + Thu, 11 Dec 2025 00:00:00 -0500 replace-cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Nino Antulov-Fantulin + Iva Ba\v{c}i\'c, Michael T. Schaub, J\"urgen Kurths, Dirk Witthaut + + + Bell Instability and Cosmic-Ray Acceleration in AGN Ultrafast Outflow Shocks + https://arxiv.org/abs/2510.13946 + arXiv:2510.13946v2 Announce Type: replace-cross +Abstract: We investigate magnetic-field amplification driven by the nonresonant hybrid (NRH or Bell) instability and its impact on cosmic-ray (CR) acceleration at reverse shocks of ultrafast outflows (UFOs) from active galactic nuclei (AGN). Previous kinetic studies by particle-in-cell simulations have demonstrated that when maximum CR energy is near the injection scale, NRH instability efficiently amplifies magnetic field up to the saturation level. However, the efficiency of NRH instability goes down as maximum energy increase since CR current is carried by escaping CRs near the maximum energy. We employ a one-dimensional MHD--CR framework solving telegraph-type diffusion--convection equations to trace the coupled evolution of CRs, magnetic fields, and shock dynamics under realistic parameters. We find a distinct transition with magnetic field strength: for weak background fields ($B_{0}\!\lesssim\!10^{-4}\,\mathrm{G}$), NRH instability efficiently amplifies upstream turbulence, driving a self-regulated state where $E_{\max}$ becomes independent of initial strength of magnetic turbulence. In contrast, for stronger background fields ($B_{0}\!\gtrsim\!10^{-3}\,\mathrm{G}$), the escaping CR current is too weak to drive NRH instability, and magnetic turbulence further decays through parametric instabilities, potentially reducing the acceleration efficiency. We give the physical interpretation for the transition and discuss conditions for PeV--EeV acceleration at UFO reverse shocks. + oai:arXiv.org:2510.13946v2 + astro-ph.HE + physics.plasm-ph + Thu, 11 Dec 2025 00:00:00 -0500 + replace-cross + http://creativecommons.org/publicdomain/zero/1.0/ + Rei Nishiura, Tsuyoshi Inoue + + + N\'eel-Vector-Orientation Induced Intrinsic Half-Metallicity in Two-Dimensional Altermagnets + https://arxiv.org/abs/2510.17522 + arXiv:2510.17522v2 Announce Type: replace-cross +Abstract: Whether a zero-moment antiferromagnet can host an intrinsic half-metallic ground state with a single-spin Fermi surface remains an open question in antiferromagnetic spintronics. Existing proposals in compensated magnets reach only transport analogues of this limit and do not realize a genuine AFM half-metallic ground state with a single-spin Fermi surface. Here we show that in two-dimensional altermagnets the N\'eel-vector orientation acts as an intrinsic knob for magnetic-space-group reduction that lifts the degeneracy between spin sectors. Using Janus monolayer Ta$_2$TeSeO as a realistic and clean platform and combining symmetry analysis with first-principles calculations, we demonstrate that rotating the N\'eel vector first breaks the relevant mirror symmetry, opening a gap in one spin sector of symmetry-related Weyl pairs, and then breaks the residual $C_{2z}$ symmetry, shifting the remaining Weyl cones in opposite energy directions so that a single spin sector retains a Fermi surface at the Fermi level. These two symmetry-lowering steps convert a compensated altermagnetic Weyl semimetal into an intrinsic AFM half-metal. The nearly degenerate in-plane magnetic anisotropy then enables reversible switching between the two spin channels using minute strain or weak anisotropic fields. Because this mechanism relies solely on N\'eel-vector-induced symmetry reduction, it provides a general low-power route to intrinsic half-metallicity in compensated altermagnetic Weyl semimetals. + oai:arXiv.org:2510.17522v2 + cond-mat.mes-hall + cond-mat.mtrl-sci + physics.comp-ph + Thu, 11 Dec 2025 00:00:00 -0500 + replace-cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Xin Chen, Jin Zou, Lipeng Song, Wei Sun, Yiwen Wu, Luyao Zhu, Xu Cheng, Duo Wang, Biplab Sanyal + + + Challenges in predicting positron annihilation lifetimes in lead halide perovskites: correlation functionals and polymorphism + https://arxiv.org/abs/2511.06926 + arXiv:2511.06926v2 Announce Type: replace-cross +Abstract: Halide perovskites have emerged in the last decade as a new important class of semiconductors for a variety of optoelectronic applications. A lot of previous studies were thus devoted to the characterisation of their point defects. Positron annihilation spectroscopy is a well recognized tool for probing vacancies in materials. Recent applications of this technique to APbX$_3$ halide perovskites are sparse, and the rare theoretical predictions of positron lifetimes in these materials, published in association with experiments, do not fully agree with each other. These works suggest that vacancies on the A site are not detected. + In our theoretical study we focus on the role of the electron-positron correlation functional. We thoroughly revisit and compare several approximations when applied to methylammonium lead iodide (MAPbI$_3$) with or without vacancies, as well as inorganic perovskites CsPbI$_3$ and CsPbBr$_3$, in various phases. We show also the relationship between the size of the voids, through Voronoi volumes, and the calculated lifetimes. For the cubic phases we investigate in detail the role of polymorphism, including the distribution of vacancy formation energies and positron annihilation lifetimes. + In our lifetimes calculations, apart from older and more recent semi-local approximations for the electron-positron correlation potential, we also consider the weighted density approximation (WDA), which is truly non-local and should better describe positron annihilation in regions with strong electronic density variations. We show that for this class of materials, and especially for cations vacancies, the influence of the chosen approximation is crucial, much stronger than in metals, alloys and conventional semiconductors. This influence may induce to reconsider the interpretation of experimentally determined lifetimes. + oai:arXiv.org:2511.06926v2 + cond-mat.mtrl-sci + physics.comp-ph + Thu, 11 Dec 2025 00:00:00 -0500 + replace-cross + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Kajal Madaan, Guido Roma, Jasurbek Gulomov, Pascal Pochet, Catherine Corbel, Ilja Makkonen + + + Entity -- Hardware-agnostic Particle-in-Cell Code for Plasma Astrophysics. I: Curvilinear Special Relativistic Module + https://arxiv.org/abs/2511.17710 + arXiv:2511.17710v2 Announce Type: replace-cross +Abstract: Entity is a new-generation, fully open-source particle-in-cell (PIC) code developed to overcome key limitations in astrophysical plasma modeling, particularly the extreme separation of scales and the performance challenges associated with evolving, GPU-centric computing infrastructures. It achieves hardware-agnostic performance portability across various GPU and CPU architectures using the Kokkos library. Crucially, Entity maintains a high standard for usability, clarity, and customizability, offering a robust and easy-to-use framework for developing new algorithms and grid geometries, which allows extensive control without requiring edits to the core source code. This paper details the core general-coordinate special-relativistic module. Entity is the first PIC code designed to solve the Vlasov-Maxwell system in general coordinates, enabling a coordinate-agnostic framework that provides the foundational structure for straightforward extension to arbitrary coordinate geometries. The core methodology achieves numerical stability by solving particle equations of motion in the global orthonormal Cartesian basis, despite using generalized coordinates like Cartesian, axisymmetric spherical, and quasi-spherical grids. Charge conservation is ensured via a specialized current deposition technique using conformal currents. The code exhibits robust scalability and performance portability on major GPU platforms (AMD MI250X, NVIDIA A100, and Intel Max Series), with the 3D particle pusher and the current deposition operating efficiently at about 2 nanoseconds per particle per timestep. Functionality is validated through a comprehensive suite of standard Cartesian plasma tests and the accurate modeling of relativistic magnetospheres in curvilinear axisymmetric geometries. + oai:arXiv.org:2511.17710v2 + astro-ph.HE + physics.plasm-ph + Thu, 11 Dec 2025 00:00:00 -0500 + replace-cross + http://creativecommons.org/licenses/by/4.0/ + Hayk Hakobyan, Ludwig M. B\"oss, Yangyang Cai, Alexander Chernoglazov, Alisa Galishnikova, Evgeny A. Gorbunov, Jens F. Mahlmann, Alexander Philippov, Siddhant Solanki, Arno Vanthieghem, Muni Zhou + + + Inductive van der Waals Force between Two Quantum Loops + https://arxiv.org/abs/2512.01263 + arXiv:2512.01263v2 Announce Type: replace-cross +Abstract: We study the van der Waals-London force, which is typically associated with fluctuating dipoles in atoms, in a mesoscopic circuit consisting of two inductively coupled superconducting loops. We investigate the ``inductive" van der Waals-London interaction using both semiclassical and quantum electrodynamic (QED) approaches. The semiclassical model predicts a repulsive interaction due to anticorrelated current fluctuations. In contrast, the QED framework, which incorporates virtual photon exchange, reveals a predominantly attractive force. A key contribution comes from a state-independent two-photon exchange, which is absent in the semiclassical description and undetectable by spectroscopy. Our study introduces a new experimental platform for measuring the van der Waals force between individual artificial atoms via controlled mesoscopic circuits. + oai:arXiv.org:2512.01263v2 + cond-mat.mes-hall + physics.atom-ph + quant-ph + Thu, 11 Dec 2025 00:00:00 -0500 + replace-cross + http://creativecommons.org/licenses/by-nc-sa/4.0/ + Kicheon Kang + + + Hamiltonian Active Matter in Incompressible Fluid Membranes + https://arxiv.org/abs/2512.03609 + arXiv:2512.03609v2 Announce Type: replace-cross +Abstract: Active proteins and membrane-bound motors exert force dipole flows along fluid interfaces and lipid bilayers. We develop a unified hydrodynamic and Hamiltonian framework for the interactions of pusher and puller dipoles embedded in an incompressible two-dimensional membrane supported by a shallow viscous subphase. Beginning from the screened Stokes equations of the membrane--subphase composite, we derive the real-space incompressible Green's tensor, obtain its near- and far-field asymptotics, and construct the resulting dipolar velocity and stream functions. Although generic dipoles reorient under the local membrane vorticity, we show that the far-field dipolar flow is vorticity-free; force-free motors therefore retain fixed orientation and obey a Hamiltonian dynamics in which the positions of $N$ dipoles evolve via an effective Hamiltonian built from the dipolar stream function. In the near field, where the flow possesses finite vorticity, a Hamiltonian formulation is recovered in the quenched-orientation limit. Exploiting this structure, we simulate ensembles of pusher and puller dipoles and compare the dynamics generated by the $1/r$ near-field kernel and the subphase screened $1/r^{3}$ far-field kernel. For identical dipoles, the far-field Hamiltonian produces rapid clustering from random initial conditions, whereas the near-field Hamiltonian suppresses collapse and yields extended, non-aggregating configurations. + oai:arXiv.org:2512.03609v2 + cond-mat.soft + physics.bio-ph + physics.flu-dyn + Thu, 11 Dec 2025 00:00:00 -0500 + replace-cross + http://creativecommons.org/licenses/by/4.0/ + Sneha Krishnan, Rickmoy Samanta + + + Progress towards a microchannel plate detector with AlGaN photocathode and cross-strip anode for ultraviolet astronomy + https://arxiv.org/abs/2512.04669 + arXiv:2512.04669v2 Announce Type: replace-cross +Abstract: Microchannel plates (MCPs) were the driving detector technology for ultraviolet (UV) astronomy over many years, and still today MCP-based detectors are the baseline for several planned UV instruments. The development of advanced MCP detectors is ongoing and pursues the major goals of maximizing sensitivity, resolution, and lifetime, while at the same time decreasing weight, volume, and power consumption. + Development efforts for an MCP-based detector system for the UV are running at IAAT at the University of T\"ubingen. In this publication, we present our latest results towards coating aluminum gallium nitride (AlGaN) photocathodes directly on MCPs, to improve quantum detection efficiency in the far- and extreme-UV. Furthermore, we report on the implementation of a non-iterative centroiding algorithm for our coplanar cross-strip anode directly in an FPGA. + oai:arXiv.org:2512.04669v2 + astro-ph.IM + physics.ins-det + Thu, 11 Dec 2025 00:00:00 -0500 + replace-cross + http://creativecommons.org/licenses/by-nc-sa/4.0/ + 10.1117/1.JATIS.11.4.042230 + Journal of Astronomical Telescopes, Instruments, and Systems, Vol. 11, Issue 4, 042230 (October 2025) + S. Diebold, J. Barnstedt, L. Conti, H. R. Elsener, L. Hanke, M. H\"oltzli, C. Kalkuhl, D. Rau, D. Schaadt, T. Schanz, B. Stelzer, K. Werner + + + High-OAM Deep Ultraviolet Twisted Light Generation for RF-Photoinjector Applications + https://arxiv.org/abs/2512.08442 + arXiv:2512.08442v2 Announce Type: replace-cross +Abstract: We report on the generation and characterization of ultraviolet (wavelength 266 nm) twisted light with high orbital angular momentum (OAM) using three types of fabricated diffractive optical elements (DOEs): a reflective fork grating, a high-charge spiral phase plate (SPP), and binary axicons. All elements were integrated into a drive-laser beamline of an electron RF-photoinjector, enabling direct evaluation under accelerator-relevant conditions. The SPP produced a high-purity Laguerre-Gaussian mode with OAM l = 64 and a measured conversion efficiency of approximately 80%. Binary axicons generated quasi-Bessel twisted light with topological charges up to m = 10, exhibiting low divergence and stable multi-lobe ring structures. The fork grating reliably produced lower-order modes, l = 2-8, with good agreement between simulations and cylindrical-lens diagnostics. These results constitute, to our knowledge, the first comprehensive experimental demonstration of deep-UV high-OAM beams generated with fabricated DOEs and validated through mode-conversion measurements. The demonstrated techniques are compatible with high-power UV laser systems used in RF-photoinjectors and offer a practical route toward structured photocathode illumination and the generation of relativistic vortex electrons at a particle accelerator facility. + oai:arXiv.org:2512.08442v2 + quant-ph + physics.acc-ph + physics.optics + Thu, 11 Dec 2025 00:00:00 -0500 + replace-cross + http://creativecommons.org/licenses/by/4.0/ + A. S. Dyatlov, D. M. Dolgintsev, V. V. Gerasimov, V. V. Kobets, V. P. Nazmov, M. A. Nozdrin, A. N. Sergeev, D. S. Shokin, K. E. Yunenko, D. V. Karlovets