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e7959cd339e1a585500e674832f36a3b63b3359c55bcdf3aa0692d11abb41311
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2026-01-23T00:00:00-05:00
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Interaction between cell membranes and protein inclusions in the large-deformation regime
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arXiv:2601.15477v1 Announce Type: new Abstract: Biological membranes are dynamic surfaces whose shape and function are critically influenced by protein inclusions (PIs). While membrane deformations induced by PIs have been extensively studied in the small-deformation regime, a variety of processes involves strong membrane deformations. We investigate the interaction between lipid membranes and PIs in the large deformation (LD) regime, with the finite-element method. We develop an approximate analytical solution that captures key features of the LD regime. We show that the force exerted by the membrane on a PI displays a non-monotonic behavior with respect to the PI vertical displacement. The qualitative features of this force appear to be independent of the protein geometry. For two interacting PIs, the membrane-mediated potential exhibits sub-power-law decay with inter-protein distance, reflecting the complex nature of the elastic medium. The interaction potential shows that conical PIs with identical and opposite orientations repel and attract, respectively, confirming the analogy between PI orientation and electric charge, in the LD regime. In the presence of membrane flows, we identify a characteristic velocity that separates two regimes in which bending rigidity and viscous effects dominate, respectively, implying the onset of flow-induced deformations above such velocity threshold. Overall, our results provide quantitative predictions for membrane-protein systems in biologically relevant scenarios involving LDs, with implications for protein sorting, clustering, and membrane trafficking.
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https://arxiv.org/abs/2601.15477
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Academic Papers
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128d5bae751ceac5f6b90ee6c1edab5bd89f82ab53346177ad5b4116c64e7b64
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2026-01-23T00:00:00-05:00
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Visualization of Gaussian Mode Profile in Gigahertz Surface-Acoustic-Wave Resonators
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arXiv:2601.15480v1 Announce Type: new Abstract: Surface-acoustic-wave (SAW) resonators operating at gigahertz (GHz) frequencies are widely used in wireless telecommunication and quantum information processing. Successful implementation of such resonators calls for detailed microscopic understanding of their mode profiles, energy dissipation channels, and imperfections from microfabrication. In this work, we report on the visualization of acoustic waves in LiNbO3 SAW resonators by transmission-mode microwave impedance microscopy (TMIM). The Gaussian mode profile tightly confined by reflecting mirrors is vividly seen in the TMIM images, from which the linewidth of the resonator itself can be extracted. The spatially resolved acoustic profile also allows us to perform failure analysis on faulty devices. Our work establishes a pathway for further optimization of SAW resonators for classical and quantum acoustic applications.
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https://arxiv.org/abs/2601.15480
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Academic Papers
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73933a3730380d2e94dadd36b0106e8bb8296026520c702e1d9e408595071b53
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2026-01-23T00:00:00-05:00
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Equivariant Interatomic Potentials without Tensor Products
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arXiv:2601.15492v1 Announce Type: new Abstract: Foundational machine-learned interatomic potentials have emerged as powerful tools for atomistic simulations, promising near first-principles accuracy across diverse chemical spaces at a fraction of the cost of quantum-mechanical calculations. However, the most accurate equivariant architectures rely on Clebsch-Gordan tensor products whose computational cost scales steeply with angular resolution, creating a trade-off between model expressiveness and inference speed that ultimately limits practical applications. Here we introduce Geodite, an equivariant message-passing architecture that replaces tensor products while incorporating physical priors to ensure smooth, well-behaved potential energy surfaces. Trained on the Materials Project trajectories dataset of inorganic crystals, Geodite-MP achieves accuracy competitive with leading methods on benchmarks for materials stability prediction, thermal conductivity, phonon-derived properties, and nanosecond-scale molecular dynamics, while running $3\text{--}5\times$ faster than models performing similarly. By combining predictive accuracy, computational efficiency, and physicality, Geodite enables faster large-scale atomistic simulations and high-throughput screening that would otherwise be computationally prohibitive.
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https://arxiv.org/abs/2601.15492
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Academic Papers
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6eaf4cfdf3b0144e3c0924b10e3eddfea8b8f8008f82758e7f0ded562b9f0fe5
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2026-01-23T00:00:00-05:00
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Convolutional LSTM Surrogate for Mesoscale Hydrocode Simulations of Granular Wave Propagation
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arXiv:2601.15497v1 Announce Type: new Abstract: Granular materials subjected to impact loading exhibit highly heterogeneous spatiotemporal dynamics governed by wave propagation, pore collapse, and grain-scale rearrangements. Mesoscale hydrocodes resolve these processes but are computationally expensive, limiting their use in parametric studies and uncertainty quantification. In this work, we develop a convolutional Long Short-Term Memory (ConvLSTM) neural network as a spatiotemporal surrogate for mesoscale simulations of weak shock propagation in granular media. Using two-dimensional hydrocode simulations as training data, we first consider a simplified "billiard break" problem in which a cue ball impacts a cluster of nine circular balls, all deformable. Sequences of pressure-field images serve as input-output pairs for a sequence-to-sequence ConvLSTM, which is trained to predict future frames from a short history. We compare several architectures and show that a relatively compact encoder-decoder ConvLSTM accurately reproduces the propagation of the pressure wave and the resulting particle motion for an unseen combination of cue-ball position and impact velocity. As a proof-of-concept extension, we apply the same ConvLSTM framework to previously published mesoscale simulations of weak shock compaction in a granular ensemble. When evaluated at piston impact speeds that were completely withheld from training, the surrogate captures the position and shape of the compaction front and its dependence on impact speed, while smoothing fine pore-scale details in the highly compacted region as expected. These results demonstrate that ConvLSTM models can serve as satisfactory surrogates for spatiotemporal mesoscale simulations of granular wave propagation, enabling accelerated exploration of parameter space and laying the groundwork for physics-informed, mesoscale simulations of granular materials under shock loading.
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https://arxiv.org/abs/2601.15497
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Academic Papers
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60fdeb5fce96d612e482c87bb5ae263081af9672300544573fbe1cad4fe9ffc2
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2026-01-23T00:00:00-05:00
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Optical Manipulation of Erythrocytes via Evanescent Waves: Assessing Glucose-Induced Mobility Variations
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arXiv:2601.15502v1 Announce Type: new Abstract: This study investigates the dynamics of red blood cells (RBCs) under the influence of evanescent waves generated by total internal reflection (TIR). Using a 1064 nm laser system and a dual-chamber prism setup, we quantified the mobility of erythrocytes in different glucose environments. Our methodology integrates automated tracking via TrackMate\c{opyright} to analyze over 60 trajectory sets. The results reveal a significant decrease in mean velocity, from 11.8 {\mu}m/s in 5 mM glucose to 8.8 {\mu}m/s in 50 mM glucose (p = 0.019). These findings suggest that evanescent waves can serve as a non-invasive tool to probe the mechanical properties of cell membranes influenced by biochemical changes.
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https://arxiv.org/abs/2601.15502
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Academic Papers
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ab6109943da50eccf2b49b3c8d0bbb9d9fb5cb27add845af0936de1ddcf17ea9
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2026-01-23T00:00:00-05:00
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Dynamical Characteristics of the Body-Caudal Fin Joint of a Carangiform Swimmer and its Influence on Hydrodynamics
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arXiv:2601.15510v1 Announce Type: new Abstract: The hydrodynamics of fish swimming depend on the interaction between the undulation of the body and the flapping of the caudal fin. This study develops a computational framework of a Jackfish-inspired swimmer with an independently mounted caudal fin that pitches passively under fluid forces and a nonlinear torsional spring. The fin synchronizes with the body when damping and stiffness parameters are tuned correctly, producing passive pitching that closely resembles to the displacement of the actively pitching tail. At Re = 3000, synchronized passive pitching generates coherent hairpin and ring vortices that reinforce streamwise momentum and contribute to thrust, whereas larger phase differences lead to wake spread in lateral direction and drag-dominated behavior. These results reveal that nonlinear peduncle mechanics naturally regulate amplitude, phase, and recoil, offering a biologically inspired pathway toward underwater robotic design using passive kinematics.
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https://arxiv.org/abs/2601.15510
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Academic Papers
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9890c8d65367fde5e3e5748b0f3005056b2729dc22c4a3782fca5a191288740c
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2026-01-23T00:00:00-05:00
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Study of the Effects of Artificial Dissipation and Other Numerical Parameters on Shock Wave Resolution
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arXiv:2601.15513v1 Announce Type: new Abstract: The effects induced by numerical schemes and mesh geometry on the solution of two-dimensional supersonic inviscid flows are investigated in the context of the compressible Euler equations. Five different finite-difference schemes are considered: the Beam and Warming implicit approximate factorization algorithm, the original Steger and Warming flux vector splitting algorithm, the van Leer approach on performing the flux vector splitting and two different novel finite-difference interpretations of the Liou AUSM+ scheme. Special focus is given to the shock wave resolution capabilities of each scheme for the solution of an external supersonic inviscid flows around a blunt body. Significant changes in the shock structure are observed, mainly due to special properties of the scheme in use and the influence of the domain transformation procedure. Perturbations in the supersonic flow upstream of the shock are also seen in the solution, which is a non-physical behavior. Freestream subtraction, flux limiting and the explicit addition of artificial dissipation are employed in order to circumvent these problems. One of the AUSM+ formulations presented here is seen to be particularly more robust in avoiding the appearance of some of these numerically-induced disturbances and non-physical characteristics in the solution. Good agreement is achieved with both numerical and experimental results available in the literature.}
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https://arxiv.org/abs/2601.15513
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Academic Papers
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fbfd033b38c85e2488bca87a4d9097bbcef5e3a54547d630c3b7caa313a1b224
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2026-01-23T00:00:00-05:00
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Numerical Aspects of Gradient Reconstruction Schemes Applied to Complex Geometries
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arXiv:2601.15522v1 Announce Type: new Abstract: This work primarily focuses on the study of three gradient reconstruction techniques applied to the calculation of viscous terms in a cell-centered, finite volume formulation for general unstructured grids. The work also addresses different ways of formulating the limiter functions necessary to maintain stability in the presence of flow discontinuities. The flows of interest are simulated using the compressible Reynolds-averaged Navier-Stokes equations, and the negative Spalart-Allmaras model is used for turbulence closure. Definition of interface inviscid terms uses the Roe approximate Riemann solver, whereas the interface viscous terms are calculated with a standard centered scheme together with appropriate definitions of the interface gradients. Steady state solutions are obtained using an implicit time-integration method, together with a novel convergence acceleration technique. This new approach defines a set of three simple rules for controlling the global CFL number based on the residue evolution. The work considers three test cases, namely, the subsonic bump-in-channel flow, the subsonic NASA high-lift Common Research Model multielement airfoil and the transonic ONERA M6 wing. Present results are compared to experimental and numerical data available in the literature. Severe numerical instabilities are observed when the simplest gradient reconstruction technique is used, while more sophisticated formulations are able to provide excellent agreement with the existing literature. Current results are demonstrated to be highly insensitive to modifications made to the numerical flux entropy fix terms. Integrated aerodynamic forces are shown to be mildly dependent on the limiter formulation used, even in the absence of shock waves. The proposed convergence acceleration procedure manages to quickly drive the residue terms to machine zero, provided no major instabilities are present.
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https://arxiv.org/abs/2601.15522
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Academic Papers
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fa812e3e56037540fed409d84be381272b0aaaa9fd744a5862040552dcb3b1ac
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2026-01-23T00:00:00-05:00
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Exploring the impacts of demand scenarios, weather variability and mitigation of emissions on Morocco's hydrogen market and renewable transition pathways
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arXiv:2601.15535v1 Announce Type: new Abstract: The global demand for green hydrogen and its derivatives is growing rapidly as a cornerstone for decarbonizing hard-to-abate sectors. Morocco, endowed with abundant solar and wind resources, ambitions to capture up to 4% of the global PtX market by 2030, positioning itself as a strategic partner for Europe's energy transition. Yet, uncertainty persists regarding European demand trajectories, infrastructure readiness, and investment risks. This study evaluates Morocco's hydrogen transition through 2035 using a sector-coupled capacity expansion model. We compare industry reallocation and hydrogen export-oriented scenarios, assessing their impacts under interannual weather variability and financial sensitivities. Both scenarios require a tripling of current renewable and electrolyzer capacities, with hydrogen demand reaching approximately up to 38 TWh by 2035. Lower financing costs (WACC) have a greater effect on system costs and competitiveness than stricter CO2 constraints or weather variability. The trade- off between domestic energy security and export competitiveness is pronounced, but both pathways are technically feasible and aligned with Morocco's strategic energy goals. These findings provide evidence-based guidance for policymakers to balance Morocco's domestic and export ambitions in the evolving hydrogen market.
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https://arxiv.org/abs/2601.15535
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Academic Papers
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22a9596fb29ad53cf74389616897a910a32b875e7df7631f2ad6a94495ff4742
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2026-01-23T00:00:00-05:00
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Can Rising Consumption Deepen Inequality?
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arXiv:2601.15537v1 Announce Type: new Abstract: The impact of rising consumption on wealth inequality remains an open question. Here we revisit and extend the Social Architecture of Capitalism agent-based model proposed by Ian Wright, which reproduces stylized facts of wealth and income distributions. In a previous study, we demonstrated that the macroscopic behavior of the model is predominantly governed by a single dimensionless parameter, the ratio between average wealth per capita and mean salary, denoted by R. The shape of the wealth distribution, the emergence of a two-class structure, and the level of inequality -- summarized by the Gini index -- were found to depend mainly on R, with inequality increasing as R increases. In the present work, we examine the robustness of this result by relaxing some simplifying assumptions of the model. We first allow transactions such as purchases, salary payments, and revenue collections to occur with different frequencies, reflecting the heterogeneous temporal dynamics of real economies. We then impose limits on the maximum fractions of wealth that agents can spend or collect at each step, constraining the amplitude of individual transactions. We find that the dependence of the inequality on R remains qualitatively robust, although the detailed distribution patterns are affected by relative frequencies and transaction limits. Finally, we analyze a further variant of the model with adaptive wages emerging endogenously from the dynamics, showing that self-organized labor-market feedback can either stabilize or amplify inequality depending on macroeconomic conditions.
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https://arxiv.org/abs/2601.15537
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Academic Papers
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f5e20dcff319efdcd6fe7866c0d27390de18c9ca647c0e9825ead9197de624da
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2026-01-23T00:00:00-05:00
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Experimental Demonstration of Nonlinear Photoconductive Gain in N-Doped $\beta$-Ga$_2$O$_3$ Devices
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arXiv:2601.15555v1 Announce Type: new Abstract: Photoconductive devices based on ultra-wide-bandgap (UWBG) materials offer a promising pathway toward compact, high-voltage (HV) optoelectronic and optical sensing in harsh environments. In this Letter, we report field-tunable nonlinear photoconductive gain in vertical $\beta$-Ga$_2$O$_3$ photoconductive devices under sub-bandgap visible-light excitation. The devices were fabricated on a $5.6\,\mu\text{m}$-thick nitrogen-doped semi-insulating $\beta$-Ga$_2$O$_3$ epilayer grown on a conductive Sn-doped substrate and characterized under $445\,\text{nm}$ continuous-wave illumination. A distinct transition from linear to nonlinear photoconductive behavior is observed at a threshold electric field of approximately $0.67\,\text{MV/cm}$, resulting in an approximately $20\times$ enhancement in photocurrent. Complementary TCAD simulations indicate strong electric-field localization and a rapid increase in impact-ionization generation at high bias, suggesting that impact-ionization--assisted carrier multiplication contributes to the observed gain. These results demonstrate a high-field visible-light photoconductive detection mode in $\beta$-Ga$_2$O$_3$ enabled by defect-assisted transport, providing a pathway toward field-tunable gain photodetectors operating without deep-ultraviolet (DUV) excitation.
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https://arxiv.org/abs/2601.15555
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Academic Papers
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9fa9c8a6f52369dd26a460c489905881f78d37d034d24321d58da13642ede686
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2026-01-23T00:00:00-05:00
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An ultrafast diamond nonlinear photonic sensor
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arXiv:2601.15562v1 Announce Type: new Abstract: The integration of light and materials technology is key to the creation of innovative sensing technologies. Sensing of electric and magnetic fields, and temperature with high spatio-temporal resolution is a critical task for the development of the next-generation of nanometer-scale quantum devices. Color centers in diamonds are attractive for potential applications owing to their characteristic quantum states, although they require metallic contacts for the introduction of external microwaves. Here, we build an ultrafast diamond nonlinear photonic sensor to assess the surface electric field; an electro-optic sensor based on nitrogen-vacancy centers in a diamond nanotip breaks the spatial-limit of conventional pump-probe techniques. The 10-fs near-infrared optical pulse modulates the surface electric field of a 2D transition metal dichalcogenide and we monitor the dynamics of the local electric field at nanometer-femtosecond spatio-temporal resolutions. Our nanoscopic technique will provide new horizons to the sensing of advanced nano materials.
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https://arxiv.org/abs/2601.15562
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Academic Papers
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b556a09e14a1c67372d517ba21cc3299f393b91e0a8acb8b3684675fbf0d8e0b
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2026-01-23T00:00:00-05:00
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Discovery of Density Limit Disruption Induced by Core-localized Alfv${\'e}$nic Ion Temperature Gradient Instabilities in a Tokamak Plasma
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arXiv:2601.15567v1 Announce Type: new Abstract: To achieve a high energy gain, the fusion reactor plasma must reach a very high density. However, the tokamak plasmas ofen undergo disruption when the density exceeds the Greenwald density. The density limit disruption in tokamak plasmas is a mysterious barrier to magnetic confinement nuclear fusion, and hitherto, is still an unresolved issue. Over the past several years, the high density experiments with Greenwald density ratio $n_e/n_{eG}\sim1$ has been carried out using the conventional gas-puff fuelling method in HL-2A NBI and Ohmically heated plasmas. It is found for the first time that there are multiple-branch MHD instabilities in the core plasmas while $n_e/n_{eG}>0.85$. The simulation analysis suggests that the core-localized magnetohydrodynamics (MHD) activities belong to Alfv${\'e}$nic ion temperature gradient (AITG) modes, and on experiment firstly, it is discovered that they trigger the minor or major disruption of bulk plasmas while the density is peaked. These new findings are of great importance to figure out and understand the origin of density limit disruptions, as well as to forecast and avoid them for future fusion rectors.
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https://arxiv.org/abs/2601.15567
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Academic Papers
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8d0de516bcf79076c742ee69b5ad235643b5cb640e698ba8b5bb0c55fe76b1b6
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2026-01-23T00:00:00-05:00
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{\sigma}h-Broken Induced Topological quasi-BIC
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arXiv:2601.15569v1 Announce Type: new Abstract: Transitions from bound states in the continuum (BICs) to quasi-BICs (qBICs) are typically realized by introducing in-plane asymmetry, including permittivity asymmetry ({\epsilon}-qBICs) and geometry asymmetry (g-qBICs). Here, we demonstrate that when the in-plane symmetry is rigorously kept, the transition can also be occurred, provided the out-of-plane asymmetry is designed, which is called {\sigma}h -qBICs in this work. When the {{\sigma}h symmetry is gradually broken, the system undergoes a topological phase transition characterized by a Zak phase inversion, leading to a band inversion between quadrupole and dipole modes. This process not only enables controlled radiation coupling of BICs but also introduces a defect-immune qBIC regime. Our findings establish a general mechanism for engineering high-Q resonances and topologically robust plasmonic cavities.
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https://arxiv.org/abs/2601.15569
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Academic Papers
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ddf6f858286cf362ecc6c25570655536afba32551576f200d4ddbb8c63c5529a
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2026-01-23T00:00:00-05:00
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Head-wearable Holographic Head-mounted Display with 6 Degrees of Freedom
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arXiv:2601.15581v1 Announce Type: new Abstract: A head-mounted display (HMD) using holography technology (holo-HMD) is expected to be the next generation of HMDs capable of reducing three-dimensional sickness. In HMDs, it is important to generate images that respond to head movement in real time. However, in holo-HMDs, generation of hologram data in real time is difficult due to the large computational resources required. This paper proposes a fast calculation algorithm for generating hologram data for holo-HMDs, which requires low computational power. A holo-HMD supporting six degrees of freedom was also developed using this algorithm and it was confirmed that it obtained reconstructed images with six degrees of freedom in real time (30 fps or more).
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https://arxiv.org/abs/2601.15581
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Academic Papers
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a603cbc72aace2a49da72f7da32a38064177a98da4384b96ac61b642f99ea300
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2026-01-23T00:00:00-05:00
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Swelling-Induced Stress-Assisted Transfer of Nanodiamond Arrays with a PVA Carrier Tape for Conformal Bio-Integrated Sensing and Labelling
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arXiv:2601.15587v1 Announce Type: new Abstract: The conformal integration of nitrogen-vacancy (NV) center nanodiamond arrays onto soft, hydrated, curvilinear biological interfaces remain a fundamental challenge for in vivo quantum sensing and imaging. Conventional transfer techniques often fail due to reliance on high temperature, corrosive chemicals, or mechanical peeling, leading to pattern damage, low fidelity, or poor biocompatibility. Here, we report a transfer strategy utilizing polyvinyl alcohol (PVA) carrier soluble tape, enabling rapid, residue-free, high-fidelity transfer of nanodiamond patterns onto diverse biointerfaces. The success of this method is rooted in a unique "hydrate-soften-expand-self-peel" mechanism of the soluble tape with PVA backing. In situ mechanical tracking reveals non-uniform PVA swelling upon hydration generates transient local normal and shear stresses at the interface. These stresses delaminate the tape within 3 minutes at room temperature while promoting adhesion of the nanodiamond array to the substrate. In contrast, conventional water-soluble tapes with composite structures undergo passive dissolution and collapse, causing residue contamination and reduced efficiency. Leveraging this mechanism, we achieve conformal patterning on ultra-soft hydrogels (~0.6 kPa) and highly curved bio-surfaces (hair, 100 {\mu}m^-1). Additionally, we demonstrate a dual-identity verification system integrating data storage and physical unclonable functions on a hydrogel contact lens. This work provides a versatile tool for bio-interface engineering and a general framework for gentle, efficient transfer of functional nanomaterials.
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https://arxiv.org/abs/2601.15587
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Academic Papers
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414add717e4263141a8d50bc3670211b89d104c867716e6fd854280b8a5e85ed
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2026-01-23T00:00:00-05:00
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Density Limit Experiments and Core-localized Kinetic MHD Activities in HL-2A Ohmic Heating Plasmas
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arXiv:2601.15590v1 Announce Type: new Abstract: The density limit is a mysterious barrier to magnetic confinement nuclear fusion, and is still an unresolved issue. In this paper, we will present the experimental results of the density limit and core-localized kinetic MHD instabilities on HL-2A. Firstly, the high density shots with $ne/ne_G>1$ have been achieved by the conventional gas-puff fuelling method in Ohmic heating plasmas, and the corresponding duration time is close to $t\sim500$ ms ($\sim$ $30\tau_E$), where $\tau_E$ is the global energy confinement time. Secondly, it is found for the first time that there are kinetic MHD instabilities in the core plasmas while $ne/ne_G\sim1$. The analysis suggests that the core-localized MHD activities belong to Alfv{\'e}nic ion temperature gradient (AITG) modes or kinetic ballooning modes (KBM), and firstly it is found on experiment that they trigger the minor or major disruption of bulk plasmas while the density profile is peaked. These new findings are of great importance to figure out and understand the origin of the density limit.
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https://arxiv.org/abs/2601.15590
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Academic Papers
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93688e70c85ebca0aced07ad9bb8acd4694fe040bf8677ba82938fe18da4e428
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2026-01-23T00:00:00-05:00
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Adaptive information-maximization encoding for ghost imaging--A general Bayesian framework under experimental physical constraints
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arXiv:2601.15604v1 Announce Type: new Abstract: Ghost imaging (GI) has demonstrated diverse imaging capabilities enabled by its encoding-decoding-based computational imaging mechanism. Accordingly, information-theoretic studies have emerged as a promising avenue for probing the fundamental performance bounds of of GI and related computational imaging paradigms. However, the design of information-theoretically optimal encoding strategies remains largely unexplored, primarily due to the intractability of the prior probability density function (PDF) of an unknown scene. Here, by leveraging the ability of recursively estimating the PDF of the object to be imaged via Bayesian filtering, we propose to establish an adaptive information-maximization encoding (AIME) design framework. Based on the adaptively estimated posterior PDF from previously acquired measurements, the expected information gain of subsequent detections is evaluated and maximized to design the corresponding encoding patterns in a closed-loop manner. Within this framework, the theoretical form of the information-optimal encoding under representative physical constraints is analytically derived. Corresponding experimental results show that, GI systems employing information-optimal encoding achieve markedly improved imaging performance compared with conventional fixed point-to-point imaging without relying on additional heuristic regularization schemes, particularly in low signal-to-noise ratio regimes. Moreover, the proposed strategy consistently enables significantly enhanced information acquisition capability compared with existing encoding strategies, leading to substantially improved imaging quality. These results establish a principled information-theoretic foundation for optimal encoding design in computational imaging paradigms,provided that the forward model can be accurately characterized.
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https://arxiv.org/abs/2601.15604
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Academic Papers
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a23851f83da46db0ce16cc7940f7e1d1def77f2f00a3ed7e1b2dab6d6450c8da
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2026-01-23T00:00:00-05:00
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A kinetic-moment framework for electron energy dynamics in capacitively coupled plasmas: absorption, conversion, transport, and dissipation
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arXiv:2601.15613v1 Announce Type: new Abstract: Understanding electron energy dynamics in low-temperature plasmas such as capacitively coupled plasmas (CCPs), including energy absorption, conversion, transport, and dissipation, is essential for interpreting discharge physics and process applications. We propose a kinetic-moment framework based on particle-in-cell/Monte Carlo collision (PIC/MCC) simulations. The framework reconstructs the first three velocity moments of the Boltzmann equation directly from PIC/MCC data and enables a quantitative, self-consistent description of electron energy dynamics in low-pressure CCPs. To clarify energy conversion among electromagnetic energy, electron fluid kinetic (mechanical) energy, and electron thermal (internal) energy, we further separate the total energy transport equation into kinetic- and thermal-energy equations. We find that, at low pressure, electrons gain directed kinetic energy in the sheath and convert it locally into thermal energy through pressure-strain interaction and collisions. Thermal energy is then transported into the bulk and is dissipated mainly by inelastic electron-neutral collisions. We further decompose pressure-strain interaction into reversible pressure dilatation and irreversible viscous-like dissipation, which correspond to conversion driven by volumetric compression or expansion and by shear deformation, respectively. This decomposition reveals a significant thermalization channel beyond collisions. More broadly, the results show coexistence of localized kinetic-to-thermal conversion near the sheath and nonlocal energy transport from the sheath to the bulk dominated by microscopic heat flux. The heat flux deviates strongly from Fourier's law based on local temperature gradients. This framework provides a clear fluid description with kinetic fidelity and offers a practical tool for analyzing energy evolution in nonequilibrium plasmas.
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https://arxiv.org/abs/2601.15613
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Academic Papers
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8095b8b0559fb0b1613576f2400786759180a92433caaf46e515942ec553916d
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2026-01-23T00:00:00-05:00
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Burst Mode Ultrafast Laser Welding of Sapphire and Fe-36Ni Alloy with Non-optical Contact Condition
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arXiv:2601.15629v1 Announce Type: new Abstract: Ultrafast laser welding provides a promising approach for high precision integration of transparent and metallic materials. However, its practical application remains constrained by the precise regulation of the interfacial gap. This study investigates the interfacial response and bonding mechanism of sapphire and Fe-36Ni alloy joints under controlled non-optical contact conditions using burst mode ultrafast laser irradiation. A polymer interlayer was introduced between naturally stacked samples to establish a variable interfacial gap, allowing systematic evaluation of gap-dependent morphology, melting behavior, and elemental transport. By redistributing the pulse energy into sequential sub-pulses, the burst mode reconstructs the temporal energy-deposition process, yielding enhanced plasma-material coupling and stable thermal accumulation. Compared with single pulse irradiation, burst mode sustains continuous bonding across gaps exceeding 10 um--far beyond the failure threshold of the single pulse mode--and forms a fusion zone 82% larger. Fracture surface and cross-sectional analyses of SEM and EDS results confirm that sequential sub-pulses promote extensive sapphire melting, droplet-driven gap bridging, and enhanced Al-Fe interdiffusion at the interface. These results provide a scientific basis for high-gap-tolerance ultrafast laser welding and scalable integration of transparent-metal hybrid components in advanced optoelectronic and precision engineering applications.
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https://arxiv.org/abs/2601.15629
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Academic Papers
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67f593d529db18c01ef1e4f233076f1fb7392d98459064c4718ccc830ada3162
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2026-01-23T00:00:00-05:00
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Structures of elastoinertial turbulence in pipe flow
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arXiv:2601.15637v1 Announce Type: new Abstract: Elastoinertial turbulence (EIT) is a self-sustaining chaotic state resulting from the interplay between inertia and elasticity in the flow of dilute polymeric solutions, and its emergence is believed to limit the achievable drag reduction in turbulence flow using polymer additives. In the present study, we introduce a viscoelastic variant of spectral proper orthogonal decomposition (VESPOD) that decomposes velocity and polymeric stress fields of EIT together into well-defined orthogonal oscillating modes such that the decomposition is optimal in the terms of the total mechanical energy of the flow. Using this technique, we investigate the dominant coherently evolving structures underlying the dynamics of EIT in axisymmetric pipe flow. By analyzing distinct peaks in the leading eigenvalue of the VESPOD eigenvalue spectrum, we find that the dynamics of EIT in pipe flow is dominated by three distinct families of traveling waves, where the higher wavenumber structures of each family are simple harmonics of their respective fundamental waves. The radial velocity fields of the traveling waves are characterized by the formation of large-scale structures spanning the pipe radial direction. However, the polymeric stress fields corresponding to them are characterized by the formation of thin inclined sheets of high stress fluctuations at the critical layers of the respective waves, i.e.~ the locations where the wave speed of the VESPOD mode matches the mean streamwise velocity. Additionally, these sheets exhibit nested structures, where the polymeric sheets of faster waves are confined by those of the immediately slower waves.
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https://arxiv.org/abs/2601.15637
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50a1c2b1d46c139574e2d14cacb76c498f183c231e3bb387862bd3faf272e60e
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2026-01-23T00:00:00-05:00
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An optical transistor of the nonlinear resonant structure
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arXiv:2601.15638v1 Announce Type: new Abstract: An optical transistor capable of simultaneous amplification and switching is theoretically proposed via cascaded second-order nonlinear interactions in a resonant structure. Two distinct operational schemes are analyzed. A single frequency scheme employs cascaded second harmonic generation and inverse second harmonic generation (SHG/iSHG) using two Type-I SHG interactions, whereas a dual frequency scheme employs cascaded SHG and optical parametric amplification (SHG/OPA). Exact theoretical solutions and numerical calculations show cascadable amplification and digital on/off switching. A new optical phenomenon of nonlinear transparency is predicted by the theoretical solutions and confirmed by the numerical solutions in each scheme of the cascaded SHG/iSHG and SHG/OPA. The single and dual frequency configurations satisfy the cascadability and fan-out criteria with power transfer ratios of 4.838 and 52.26 and power amplification factors of 48.38 and 522.6, respectively. These results indicate transistor-like performance at input powers in the milliwatt range, readily supplied by laser diodes. The proposed structure establishes a physically feasible and practically scalable route to optical transistors operating at high speed and low power for integrated photonic circuits, with broad applications in all optical communication and computing.
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https://arxiv.org/abs/2601.15638
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570034cda70f4362dd118e3982e971e9400361f6e3400c0e1f7be6cda977e299
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2026-01-23T00:00:00-05:00
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Scaling-Based Quantization of Spacetime Microstructure
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arXiv:2601.15649v1 Announce Type: new Abstract: Planck-scale physics challenges the classical smooth-spacetime picture by introducing quantum fluctuations that imply a nontrivial spacetime microstructure. We present a framework that encodes these fluctuations by promoting local scale factors, rather than the metric tensor, to fundamental dynamical variables while preserving general covariance. The construction employs a two-tiered hierarchy of scale manifolds, comprising a first-order manifold of scale coordinates and a second-order manifold of fluctuation amplitude coordinates. On the first-order manifold, we formulate differential geometry, field equations, and a canonical quantization procedure. The theory yields a geometric renormalization-group flow for scale variables and implies spacetime discreteness at the microscopic level. By constructing a quadratic action and performing spectral decomposition with a stabilizing potential, we obtain discrete modal degrees of freedom quantized as harmonic oscillators. The framework proposes a microscopic description for zero-point energy of spacetime and explores implications for vacuum energy and ultraviolet regularization, suggesting a potential dynamical mechanism that could ameliorate the cosmological constant problem. Main results include a generalized uncertainty relation with scale-dependent coefficients, locally scaled Klein-Gordon and Dirac equations, geodesic equations for scale spacetime, and a microscopic area operator whose state counting is consistent with the Bekenstein-Hawking entropy. This work develops a scale-based quantization procedure, providing a foundation for further mathematical analysis and phenomenological tests of spacetime quantization.
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https://arxiv.org/abs/2601.15649
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7766b088e0fccadee9861dcf267f46f51dfc5270c2e8b378a8f96e54b9904a24
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2026-01-23T00:00:00-05:00
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Toward Trustworthy Short-Range Forecasts with AFNO: From Skill Metrics to Conservation Checks
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arXiv:2601.15660v1 Announce Type: new Abstract: Data driven weather models now approach traditional numerical weather prediction (NWP) skill at short to medium lead times, but their dynamical consistency during autoregressive rollout remains uncertain.
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https://arxiv.org/abs/2601.15660
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2e9bc9adcbc6ad2208c9d1e1dda99dc7ac4352826baf60aa078b90bc732ff5cc
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2026-01-23T00:00:00-05:00
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Non-Ambipolarity of Microturbulent Transport
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arXiv:2601.15661v1 Announce Type: new Abstract: Even what is called electrostatic microturbulence produces a plasma-beta-dependent turbulent magnetic field $\tilde{B}$, which makes the magnetic field lines chaotic. Quasi-neutrality along the chaotic magnetic field lines requires a potential that obeys $\vec{B}\cdot \vec{\nabla} \Phi = \vec{B}\cdot \vec{\nabla} p_e$, where $p_e$ is the electron pressure. This potential produces radial transport similar to that of diffusion coefficient $D_{ef}= (\Delta/a_T)T_e/eB$. $\Delta$ is the radial distance over which the potential $\Phi$ is correlated by the electron motion along the chaotic magnetic field, and $|dT_e/dr| = T_e/a_T$. The chaos-produced electron transport gives an effective viscosity on the electron flow, which can counter balance a non-ambipolar part of the ion radial particle diffusion $f_{na}$. This non-ambipolarity would otherwise require a radial electric field that confines ions and hence impurities. The maximum $f_{na}$ that can be counterbalanced and the required plasma beta to avoid shielding the magnetic perturbations $\tilde{B}$ are calculated.
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https://arxiv.org/abs/2601.15661
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82d4fcbec8e80ffebfc22fff9f86b3eb184dcf57b1f6a3a934e5bd8a7468e4e2
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2026-01-23T00:00:00-05:00
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Blue to Near-IR Integrated PZT Silicon Nitride Modulators for Quantum and Atomic Applications
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arXiv:2601.15695v1 Announce Type: new Abstract: Modulation and control of lasers and optical signals is necessary for trapped-ion and cold neutral atom quantum systems. Given the diversity of atomic species, experimental modalities, and architectures, integrated optical modulators designed to operate across the visible to near-infrared spectrum are a key step towards portable, robust, and compact quantum computers, clocks, and sensors. Integrated optical modulators that are wavelength-independent, CMOS-compatible, and capable of maintaining low waveguide losses and a high resonator quality factor, DC-coupled broadband frequency response, and low power consumption, are essential for scalable photonic integration. Yet progress towards these goals has remained limited. Here we demonstrate four types of integrated stress-optic lead zirconate titanate (PZT) silicon nitride modulators: a coil Mach-Zehnder modulator, a coil pure phase modulator, and bus-coupled and add-drop ring resonator modulators, with operation from 493 nm to 780 nm. The coil MZM operates at 532 nm with a V${\pi}$ of 2.8V, a 0.4 MHz 3-dB bandwidth, and an extinction ratio of 21.5dB. The coil phase modulator operates at 493 nm with a V${\pi}$ of 2.8V and low residual amplitude modulation of -34 dB at a 1kHz offset. The bus-coupled ring resonator modulator operates at 493 nm and the add-drop ring resonator modulator operates at 780 nm. The ring-based modulators have an intrinsic quality factor of 3.4 million and 1.9 million, a linear tuning strength of 0.9 GHz/V and 1 GHz/V, and a 3-dB bandwidth of 2.6 MHz and 10 MHz, respectively. All four modulator designs maintain the low optical waveguide loss of SiN, are DC coupled with broadband frequency response, operate independent of wavelength, and consume only tens of nW per actuator. Such solutions unlock the potential for further integration with other precision SiN components to realize chip-scale atomic and quantum systems.
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https://arxiv.org/abs/2601.15695
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b4e7c9bf1c1ab14bf32f7716384a6fad85f76438a3a74c16167d02a2a9fc8675
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2026-01-23T00:00:00-05:00
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Monolithic tantalum pentoxide microrings with intrinsic Q factors exceeding 4X10(6)
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arXiv:2601.15753v1 Announce Type: new Abstract: Tantalum pentoxide (Ta2O5), as a silicon-photonic-compatible material platform, has garnered significant attention for high-performance integrated photonics due to its exceptional properties: a broad transparency window spanning from 0.28 um to 8 um, a moderate refractive index of 2.05 at 1550 nm, and an impressive nonlinear refractive index of 7.2X10^(-19) m^2/W. Despite these advantages, achieving low-loss fabrication of monolithic microrings on the Ta2O5 platform remains challenging due to its inherent hardness and brittleness, which often result in rough sidewalls and significant scattering losses. In this work, we successfully demonstrated monolithic Ta2O5 microring resonators with exceptionally high intrinsic and loaded quality (Q) factors. This was accomplished through the innovative application of photolithography-assisted chemo-mechanical etching (PLACE) technology. By optimizing the coupling region between the microring and the bus waveguide, as well as meticulously controlling surface roughness during fabrication, we achieved near-critical coupling in the resulting microrings. The devices exhibited loaded Q factors of 2.74X10(6) in the telecom band without employing expensive electron-beam lithography, showing an intrinsic Q factor as high as 4.47X10(6) and a low propagation loss of only 0.0732 dB/cm - representing the highest results reported for strongly confined Ta2O5-based microring resonators to date. This work paves the way for the development of advanced photonic devices on the Ta2O5 platform with low manufacturing cost, including low-threshold microlasers, highly sensitive sensors, broad bandwidth supercontinuum sources, and optical frequency combs.
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https://arxiv.org/abs/2601.15753
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1993a7e506b0dc3901bba392d67450764403a919bac4ba0d58a69e306e987096
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2026-01-23T00:00:00-05:00
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Multi-Scale Irregularities Product: a data product utilizing the high-resolution Swarm plasma density data for space weather applications
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arXiv:2601.15762v1 Announce Type: new Abstract: We use the high-resolution Swarm faceplate plasma density data at 16 Hz to develop a set of parameters that can characterize multi-scale ionospheric structures and irregularities along the Swarm orbit. We present the methods for calculating density gradients over different window sizes, rate of change of density index, power spectral density and the spectral slope at both low and high latitudes. The faceplate plasma data are not continuously available through the years. However, about 8 years of data from Swarm A are processed from late 2014 to the end of 2025. Some statistical results from Swarm A are presented. The variations of plasma structures and irregularities are dependent on solar activity, season, local time and geomagnetic activities, and the variations show different patterns between low and high latitudes. For example, the high-latitude ionosphere is characterized by persistent ionospheric structures and irregularities poleward of 60 magnetic latitude, while the low-latitude ionospheric irregularities are only dominant during 19-01 local time near the magnetic equator. The occurrence of steep spectral slope at high latitudes shows clear seasonal variations, i.e., it maximizes during local summer and minimizes during local winter in both hemispheres. However, the occurrence of steep spectral slope at low latitudes is only sensible when significant plasma structures and irregularities are present. We further calculate the histogram of spectral slopes at low latitudes when the rate of change of density index is enhanced. The histogram resembles a Gaussian distribution with an expected value of 1.97. The processed data are available to the wider community. Given the high resolution, this new data product will be useful for the scientific communities that are interested in the magnetosphere-ionosphere-thermosphere coupling and near-Earth space environment.
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https://arxiv.org/abs/2601.15762
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4aaff290f1ba9af12dfc48a6026207c4b895c0ab2031a55ba03d065f21313483
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2026-01-23T00:00:00-05:00
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Explainable deep-learning detection of microplastic fibers via polarization-resolved holographic microscopy
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arXiv:2601.15769v1 Announce Type: new Abstract: Reliable identification of microplastic fibers is crucial for environmental monitoring but remains analytically challenging. We report an explainable deep-learning framework for classifying microplastic and natural microfibers using polarization-resolved digital holographic microscopy. From multiplexed holograms, the complex Jones matrix of each fiber was reconstructed to extract polarization eigen-parameters describing optical anisotropy. Statistical descriptors of nine polarization characteristics formed a 72-dimensional feature vector for a total of 296 fibers spanning six material classes, including polyamide 6, polyethylene terephthalate, polyamide 6.6, polypropylene, cotton and wool. The designed fully connected deep neural network achieved an accuracy of 96.7 % on the validation data, surpassing that of common machine-learning classifiers. Explainable artificial intelligence analysis with Shapley additive explanations identified eigenvalue-ratio quantities as dominant predictors, revealing the physical basis for classification. An additional reduced-feature model with the preserved architecture exploiting only these most significant eigenvalue-based characteristics retained high accuracy (93.3 %), thereby confirming their dominant role while still outperforming common machine-learning classifiers. These results establish polarization-based features as distinctive optical fingerprints and demonstrate the first explainable deep-learning approach for automated microplastic fiber identification.
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https://arxiv.org/abs/2601.15769
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ca2406ce1d9c07ffe9c217a9a2ba941df508960e1ddfdf2841775e4414c21769
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2026-01-23T00:00:00-05:00
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Coherent Mode Decoupling: A Versatile Framework for High-Throughput Partially Coherent Light Transport
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arXiv:2601.15776v1 Announce Type: new Abstract: Accurate and efficient wave-optics simulation of partially coherent light transport systems is critical for the design of advanced optical systems, ranging from computational lithography to diffraction-limited storage rings (DLSR). However, traditional approaches based on Coherent Mode Decomposition suffer from high computational costs due to the propagating massive sets of two-dimensional modes. In this paper, we propose the Coherent Mode Decoupling (CMDC) algorithm, a high-throughput computational framework designed to accelerate these simulations by orders of magnitude without compromising physical fidelity. The method factorizes 2D modes into efficient one-dimensional (1D) components, while crucially incorporating a subspace compression strategy to capture non-separable coupling effects. We demonstrated the generality and robustness of this framework in applications ranging from computational lithography to coherent beamlines of DLSR.
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https://arxiv.org/abs/2601.15776
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42ba9acb94e945fee44e3bda1cbc4553b5120bfdced8e55b8ccf99a2304fb762
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2026-01-23T00:00:00-05:00
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On the effect of force on DNA in the Peyrard-Bishop-Dauxois model
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arXiv:2601.15792v1 Announce Type: new Abstract: This paper presents a numerical study of the dynamics of DNA double helix breakage under the influence of external forces using the Peyrard-Bishop-Dauxois (PBD) model. The PBD model represents DNA as a chain of nonlinearly coupled oscillators, which makes it possible to analyze the processes of melting and mechanical denaturation. The main focus is on cases where an external force is applied to the terminal or central site of a DNA molecule, simulating stretching at a constant rate. The critical force required to break hydrogen bonds, which depends on the point of application of the force, is calculated. It is found that the denaturation process occurs stepwise, with characteristic peaks in the force-time graphs. The phenomenon of hysteresis under periodic exposure to external forces is also studied, which is important for understanding energy losses and heating of the system.
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https://arxiv.org/abs/2601.15792
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ad10340611112ce8521b5ad79871bef5b22ecd528d651bcbe41a475082453196
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2026-01-23T00:00:00-05:00
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Photorefraction Management in Lithium Niobate Waveguides: High-Temperature vs. Cryogenic Solutions
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arXiv:2601.15817v1 Announce Type: new Abstract: Lithium niobate sees widespread use in nonlinear and quantum optical devices, such as for sum- and difference-frequency generation or spontaneous parametric down-conversion. In lithium niobate waveguides, nonlinear optical processes are often limited by the so-called photorefractive effect, which limits the maximum input or output powers and impacts the nonlinear spectral response. Therefore, strategies for the management of photorefractive damage are a key consideration in device design. Usually, the photorefractive damage threshold, i.e. the maximal permissible operating power, can be increased by high temperature operation of devices. This approach, however, is not applicable in cryogenic environments, which may be required for specialized applications. To better understand the impact of photorefraction in nonlinear optical applications, we study the impact of photorefraction on the phase-matching spectra of two nonlinear-optical sum-frequency generation experiments at 1) high temperatures and 2) cryogenic temperatures. Furthermore, we present an approach to reduce the impact of photorefraction which is compatible with cryogenic operation. This comprises an auxiliary light source, propagating in the same waveguide, which is used to restore phase-matching spectra impacted by photorefraction, as well as reduce pyroelectric effects. Our work provides an alternative route to photorefraction management applicable to cryogenic environments, as well as in situations with tight energy budgets like space applications.
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https://arxiv.org/abs/2601.15817
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56c9cee4ac85d2232a556aab7d2f213cfd19b1148ac213df577e031b977123c6
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2026-01-23T00:00:00-05:00
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Determination of the longitude difference between Baghdad and Khwarezm using a lunar eclipse (the method of Abu Rayhan al-Biruni and Abu al-Wafa al-Buzjani)
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arXiv:2601.15837v1 Announce Type: new Abstract: This paper examines how, in the tenth century, medieval Iranian scholars Abu Rayhan al-Biruni and Abu al-Wafa al-Buzjani determined the difference in geographical longitude between the cities of Baghdad and Khwarezm through simultaneous observation of a lunar eclipse. Brief academic biographies of these scholars are presented, with emphasis on their contributions to mathematics and astronomy. The study discusses the importance of determining geographical coordinates - especially longitude - in the science of the 10th-11th centuries, provides an overview of the methods of coordinate determination available at the time, and highlights the problem of synchronizing remote observations prior to the advent of electronic communication. Particular attention is devoted to a detailed analysis of the method based on observing a lunar eclipse to simultaneously measure longitude differences: the necessary conditions and organization of the experiment, the instruments employed, the mathematical calculations, and error estimates are described. The longitude difference obtained by al-Biruni and al-Buzjani is compared with modern values. The conclusion discusses the scientific significance of this method for the history of science and astronomy.
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https://arxiv.org/abs/2601.15837
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4be77792b416bff051cf21e1d9061e3235ee4736e42d1d2cc45acdb628b9dbfd
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2026-01-23T00:00:00-05:00
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Turbulent hydrogen premixed flames at high pressure and high temperature
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arXiv:2601.15848v1 Announce Type: new Abstract: The combined influence of elevated pressure and temperature, representative of gas-turbine operating conditions, on lean premixed hydrogen flames is investigated using Direct Numerical Simulations (DNS) of a turbulent jet. Three cases are considered: 1 atm/298 K, 5 atm/472 K, and 20 atm/700 K, scaled to maintain the same jet Reynolds number and nominal Karlovitz number in the unburnt mixture, enabling a direct comparison of flame-turbulence interactions. Although the combined effects are moderate overall due to compensating influences, measurable differences arise in flame structure and turbulence-flame coupling. They are driven by reduced turbulence dissipation within the flame at high pressure and temperature, which enhances the interaction between turbulence and thermodiffusive effects. Finally, the tangential strain rate exhibits the same universal Kolmogorov scaling observed in homogeneous-isotropic turbulence and in methane flames, confirming its robustness for modelling turbulence
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https://arxiv.org/abs/2601.15848
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0de3529ef550b59c0dd7163e64b7742a922dfbd1f57c5fff1d77e30350cb14c1
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2026-01-23T00:00:00-05:00
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Dynamics of antiferromagnetic Dimers in Rydberg Atom Chains
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arXiv:2601.15866v1 Announce Type: new Abstract: We investigate the dynamics of antiferromagnetic dimers within a Rydberg atom chain in the regime where laser detuning compensates for nearest-neighbor (NN) interactions. Using an effective PXQ model, we demonstrate that the associated Hilbert space decomposes into disconnected, dimer-conserving subspaces. The classification of these subspaces is provided, and the computational basis states spanning them are identified. Through a combination of analytical mapping and numerical simulations, we compare the dynamics of the PXQ model with those of the full Rydberg atom chain. The deviations are attributed to two factors, laser-induced leakage from the constrained Hilbert subspace and the influence of long-range interactions beyond the NN limit. Our results indicate that subspace leakage can be mitigated by increasing the NN interaction strength. While this simultaneously amplifies the effects of long-range interactions, the conservation of the dimer number remains. Our study opens up possibilities for exploring the dynamics of antiferromagnetic dimers using the Rydberg atom quantum simulator.
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https://arxiv.org/abs/2601.15866
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cd8c74012f1407255366f5c02267720d6406ee15b79fc6561cf2abfd3ce1ffb8
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2026-01-23T00:00:00-05:00
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Large-scale real-time signal processing in physics experiments: The ALICE TPC FPGA pipeline
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arXiv:2601.15868v1 Announce Type: new Abstract: For LHC Run 3, the ALICE Time Projection Chamber was upgraded to operate in continuous readout mode. Interaction rates of up to 50 kHz in Pb-Pb collisions require real-time processing of more than 3 TB/s of raw detector data. This requirement is met by a custom FPGA-based processing pipeline that performs the complete front-end data treatment fully in-stream, including common-mode correction, pedestal subtraction, ion-tail filtering, zero suppression, and dense data packing. A central element of the design is a highly parallel common-mode correction algorithm operating directly on the streaming data. It robustly identifies signal-free readout channels on a time-bin basis and applies pad-dependent scaling to compensate for local variations in capacitive coupling in the GEM readout. In combination with pedestal subtraction and ion-tail filtering, this enables accurate baseline restoration under extreme high-occupancy conditions, preventing signal loss while efficiently suppressing noise prior to zero suppression. The pipeline operates continuously at the full detector bandwidth and reduces the raw input rate to about 900 GB/s for Pb-Pb collisions at the target interaction rate. Overall, it represents a large-scale FPGA-based real-time signal-processing implementation for high-energy physics detector readout.
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https://arxiv.org/abs/2601.15868
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6b6f942395323160c3ffc3aeba60094c07d760f8b6bef030742655e17332951c
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2026-01-23T00:00:00-05:00
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Size-dependent Dielectric Permittivity of Perovskite Nanocrystals
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arXiv:2601.15898v1 Announce Type: new Abstract: Perovskite nanocrystals (PNCs) are promising building blocks for quantum photonic devices. Optical properties of PNCs can be enhanced by integration with optical cavities or nanoantennas. Designing such structures requires accurate size dependent dielectric permittivity of PNCs. However, current reports provide primarily ensemble averaged values with limited access to the intrinsic response of individual PNCs. Here we suggest a methodology to reconstruct the size dependent complex dielectric permittivity of CsPbBr3 PNCs from the measured absorbance spectrum of colloidal solution. The permittivity of PNCs is modeled as a sum of Voigt profile oscillators, with the size dependent transition energies governed by the exciton effective mass. Using a transmission electron microscopy derived size distribution of the PNCs, the solution permittivity is obtained via Maxwell Garnett effective medium approximation. This permittivity is used in a transfer matrix method to simulate and fit the absorbance spectrum, from which the permittivity of PNCs is reconstructed. The extracted spectral linewidth from the imaginary part of the permittivity (78.4 meV) is consistent with single nanocrystal emission linewidths at room temperature. Finite element simulations show enhanced absorption cross section of a single PNC coupled to a nanoantenna, demonstrating applicability of the extracted permittivity. More generally, these findings provide a route to extract intrinsic permittivity of individual nanocrystals from absorbance measurements of their ensembles.
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https://arxiv.org/abs/2601.15898
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fff04602493be8aeb9a4d6277e09068bdc126eb458c9c1f0f13278318513c022
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2026-01-23T00:00:00-05:00
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Quantitative absorption tomography
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arXiv:2601.15925v1 Announce Type: new Abstract: Brightfield microscopy is central to wide range of biology, engineering, and histopathology; but is inherently limited to two-dimensional qualitative imaging, systematically investigating three-dimensional (3D) volumetric architecture. Here we introduce quantitative absorption tomography (QAT), a computational approach that quantitatively reconstructs high-resolution volumetric absorption coefficient distributions from brightfield focal stacks. By modeling absorption image formation in logarithmic intensity space and applying deconvolution with an absorption optical transfer function, QAT enables quantitative, spectrally resolved 3D absorption imaging without interferometry, sample rotation, or specialized hardware. We validate QAT using spectrally selective phantoms and demonstrate absorption-specific contrast complementary to refractive index tomography in living melanocytes and intact plant tissue. QAT further scales to millimeter-scale volumes of H&E-stained human tissue, revealing 3D histological microarchitecture without serial sectioning. This approach extends brightfield microscopy toward practical 3D histopathology.
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https://arxiv.org/abs/2601.15925
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41bae74196cb6443d14ea43b71a72d168a54770f40b6f8dca739fd96df3cf703
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2026-01-23T00:00:00-05:00
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OPTIMA, a board dedicated to Optimized Precision Timing for Multichannel Acquisition
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arXiv:2601.15937v1 Announce Type: new Abstract: In the new era of HL-LHC experiments, fast-timing detectors are emerging as critical tools for background rejection. Typical requirements include a temporal hit resolution of about 50 ps, a spatial resolution of around 12 $\mu$m, and radiation hardness up to $10^{17}$n$_\text{eq}$/cm$^2$. To address these challenges, the development of non-standard sensor designs and advanced fast readout electronics is required. The OPTIMA multichannel board addresses the need for testing small sensor demonstrators when they cannot yet be bonded to dedicated readout ASICs. It provides fast readout of up to 16 channels and can be integrated into various test setups, including test beam environments. This contribution presents the design of the OPTIMA board, its integration in test beams, and the first experimental results.
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https://arxiv.org/abs/2601.15937
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404a643e7a3c1f862bfe4d4af421eb5586084e3f839541c907a6299b775982fe
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2026-01-23T00:00:00-05:00
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Operating a large-diameter dual-phase liquid xenon TPC in the unshielded PANCAKE facility
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arXiv:2601.15938v1 Announce Type: new Abstract: Future liquid-xenon (LXe) based observatories for rare processes, such as XLZD, require testing of large components and sub-assemblies in cryogenic liquid or gaseous xenon environments. Here we present results from the stable operation of a shallow dual-phase LXe TPC with an inner diameter of 133.4\,cm and a height of 3.1\,cm in the unshielded PANCAKE platform, without underground suppression of cosmic-ray backgrounds. A total of 340\,kg of xenon was used in the experiment, of which 127\,kg constituted the active TPC mass. Measurements of the LXe purity-dependent electron lifetime and the electron drift velocity in LXe demonstrate that sensitive measurements to characterize the TPC performance are possible in a high-background environment, even with a very basic PMT-based light detection system. Improving this will straightforwardly reduce the TPC threshold, which was observed to be around 15\,keV for electronic recoils in TPC operation.
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https://arxiv.org/abs/2601.15938
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b9479079e8e31ea10413ed68f2ca9c17e492abff8e01c1f9837296649df6877a
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2026-01-23T00:00:00-05:00
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Partitioning networks into clusters of synchronized nodes via the message-passing algorithm: an unbiased scalable approach
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arXiv:2601.15944v1 Announce Type: new Abstract: Partitioning large networks into stable clusters of synchronized nodes is a challenging task. Recent approaches based on spectral analysis can provide exact results on specific dynamics but remain unfeasible for very large networks. Moreover, within a stochastic framework, it is unclear which dynamics should be chosen to study synchronization. Here we propose an unbiased and scalable method based on the message-passing algorithm. By exploiting the collective behavior emerging across critical points of an effective Ising-like model, we identify dynamically coherent clusters of synchronized nodes and illustrate the approach on some large real-world networks. We find that, unlike continuous-time dynamics, abrupt desyncrhronization occurs even in simple graphs, without the need to invoke higher order interactions. However, when noise is included, the transition to synchronization becomes smoother and proceeds through the formation of plateaus, albeit at the cost of requiring larger coupling strengths.
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https://arxiv.org/abs/2601.15944
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89ba95cc3b1331bef89bd69e7e838e3d8be6cb5632c75f9068c8cdcaaf72039f
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2026-01-23T00:00:00-05:00
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Multimodal Imaging System Combining Hyperspectral and Laser Speckle Imaging for In Vivo Hemodynamic and Metabolic Monitoring
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arXiv:2601.15947v1 Announce Type: new Abstract: We present the development and validation of a novel multimodal optical imaging platform that integrates hyperspectral imaging (HSI) and laser speckle contrast imaging (LSCI) to enable real-time, non-invasive mapping of tissue oxygenation, perfusion and metabolism, via blood flowmetry and targeting of oxy- (HbO2), deoxyhemoglobin (HHb), as well as oxidized cytochrome-c-oxidase (oxCCO). The system architecture features a single high-speed camera and dual optical path, with synchronized alternating illumination: a filtered, supercontinuum laser for HSI and a He-Ne laser for LSCI. The system performances were evaluated through in vivo experiments on rat spinal cord under normoxic and hypoxic conditions, revealing coherent physiological changes in hemodynamics, metabolism and relative blood flow index (rBFI). These results demonstrate the potential of the platform for functional tissue imaging and quantitative dynamic monitoring of both oxygen delivery and consumption.
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https://arxiv.org/abs/2601.15947
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bdc966166ac0529a54e2f71e7263eee3f7ce1fc76af23cd0fe7ab85f27f21287
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2026-01-23T00:00:00-05:00
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Response of fluorescent molecular rotors in ternary macromolecular mixtures
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arXiv:2601.15967v1 Announce Type: new Abstract: For a few decades, Fluorescent Molecular Rotors have been commonly employed as local probes of microviscosity in complex materials. However, without proper calibration, relating microviscosity to a physical parameter is unclear, which strongly limits their quantitative use in biological media for instance. In this study, the response of a molecular rotor in binary and ternary macromolecular aqueous solutions of polyethylene glycol (PEG) of different molecular weights is investigated in order to better rationalize the sensitivity of rotors to their cybotactic environment. More precisely, for the investigated composition range of ternary mixtures, it is shown that a linear mixing rule applies for fluorescence lifetime with the proportion of the two PEG, and with an increasing ratio of heavy PEG leading to larger lifetimes. These results allow to test more precisely the free volume theory, which has been proposed in the context of probing glass transition. Analysis show that while this theory semi-quantitatively captures the observation, its precise use raises some questions.
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https://arxiv.org/abs/2601.15967
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8a2944eebc40ceec90043d5d1172f6d418222b314945eafb4af48f0e3cbce6b0
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2026-01-23T00:00:00-05:00
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Assimilating rough features: A data-driven framework to infer rough wall properties from sparse experimental data
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arXiv:2601.15980v1 Announce Type: new Abstract: Surface roughness influences turbulent boundary layers (TBLs) primarily through the roughness function $\Delta U^+$ and the equivalent sand-grain roughness height \(k_s\). Direct determination of \(k_s\) typically requires detailed velocity and wall-shear stress measurements, which are often impractical. As an alternative, this study presents a data assimilation framework that modifies a smooth-wall Reynolds-Averaged Navier-Stokes (RANS) baseline to match sparse rough-wall particle image velocimetry (PIV) data in the fully rough regime. Through this approach, secondary variables such as the friction velocity, \(u_\tau\), and \(k_s\) can be inferred from the assimilated flow fields. The assimilated TBL reproduces experimental velocity profiles within 1\% and predicts friction velocity within 1-6\% of the experimental measurements. Furthermore, the \(k_s\) values inferred from the assimilation also match the experimental data up to 1\%. These results demonstrate the potential of data assimilation as a cost-effective alternative to high-fidelity methods and support the generalisation of the framework to model streamwise-varying roughness by treating \(k_s\) as a function of fetch length.
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https://arxiv.org/abs/2601.15980
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Academic Papers
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f12b434cde7ee25ab645c93dd77e8b4acd36a3df7d8b1323254869eb69a03a36
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2026-01-23T00:00:00-05:00
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Mid-infrared high-sensitive cavity-free in-situ CO gas sensing based on up-conversion detection
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arXiv:2601.15981v1 Announce Type: new Abstract: Carbon monoxide (CO) is a significant indicator gas with considerable application value in atmospheric monitoring, industrial production and medical diagnosis. Its fundamental vibrational band locates around 4.6 $\upmu$m and has larger absorption line strength than that of overtone band, which is more suitable for the precise identification and concentration detection of CO. In this paper, the up-conversion detection is employed to convert the mid-infrared absorption signal obtained by TDLAS to the visible light band, then a silicon-based detector is utilized for detection. By which, we can achieve the highest sensitivity of 79.6 ppb under the condition of cavity-free in-situ with an absorption range length of only 0.14 m. Furthermore, the single-photon level real-time detection of CO concentration after the diffuse reflection is realized by using SPAD. This work demonstrates the merits of the up-conversion detection in terms of its functionality at room temperature and capacity for sensitivity detection. Furthermore, it presents a design and optimization methodology that has the potential to underpin the advancement of the method towards more practical applications, like industrial process monitoring, medical diagnosis and so on.
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https://arxiv.org/abs/2601.15981
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Academic Papers
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a5ead134ba8df1dc010e25b21cce9bcbd3a777b19c1c15ee8cf78f6482678684
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2026-01-23T00:00:00-05:00
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On-chip Multimode Opto-electronic Neural Network
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arXiv:2601.15989v1 Announce Type: new Abstract: Opto-electronic computing combines the complementary strengths of photonics and electronics to deliver ultrahigh computational throughput with high energy efficiency. However, its practical deployment for real-world applications has been limited by architectures that rely on delicate wavelength management or phase-sensitive coherent detection. Here, we demonstrate the first multimode opto-electronic neural network (MOENN) on a silicon-on-insulator platform. By utilizing orthogonal waveguide eigenmodes as independent information carriers, our architecture achieves robust single-wavelength computation that is inherently immune to spectral crosstalk and phase noise. The fabricated MOENN chip monolithically integrates all functional components, including input encoders, programmable mode-division fan-in/-out units, and most importantly, the nonlinear multimode activation functions. We report the system's versatility through in-situ training via a genetic algorithm, successfully resolving the nonlinear decision boundaries of a two-class dataset and achieving 92.1% accuracy on the Iris classification benchmark. Furthermore, we reconfigure the MOENN into a one-dimensional convolutional neural network, attaining an accuracy of 90.7% on the electrocardiogram-based emotion recognition task. This work establishes a new opto-electronic computing paradigm of simple control and excellent robustness, providing a compelling path toward scalable, deployable photonic intelligence.
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https://arxiv.org/abs/2601.15989
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d73accf5b1aec65a743c88571613638d3046da1fc438cedddaacec3e25069688
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2026-01-23T00:00:00-05:00
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Application of zone refining to the development of NaI(Tl) detectors for SABRE North
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arXiv:2601.15998v1 Announce Type: new Abstract: The SABRE North experiment is developing ultra-high radiopurity NaI(Tl) detectors to investigate dark matter. To achieve this, SABRE North utilizes the technique called zone refining for NaI powder purification. This work details the mathematical model developed to describe the purification process. By comparing this model to the results of the commissioning and production runs conducted prior to crystal growth, the distribution coefficients were determined for various impurities, contained in the powder at the parts-per-billion (ppb) level. Furthermore, the synthesis of data from both zone refining and normal freezing is discussed. These findings can be used to predict the SABRE North detectors background level in the energy region-of-interest for dark matter search and to optimize the production of ultra-high purity crystals through multiple purification strategies.
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https://arxiv.org/abs/2601.15998
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9011cd09514e510543099f4363358b2fdef18602536597f3d3860f5cb8390c52
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2026-01-23T00:00:00-05:00
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Enhanced Representation-Based Sampling for the Efficient Generation of Datasets for Machine-Learned Interatomic Potentials
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arXiv:2601.16047v1 Announce Type: new Abstract: In this work, we present Enhanced Representation-Based Sampling (ERBS), a novel enhanced sampling method designed to generate structurally diverse training datasets for machine-learned interatomic potentials. ERBS automatically identifies collective variables by dimensionality reduction of atomic descriptors and applies a bias potential inspired by the On-the-Fly Probability Enhanced Sampling framework. We highlight the ability of Gaussian moment descriptors to capture collective molecular motions and explore the impact of biasing parameters using alanine dipeptide as a benchmark system. We show that free energy surfaces can be reconstructed with high fidelity using only short biased trajectories as training data. Further, we apply the method to the iterative construction of a liquid water dataset and compare the quality of simulated self-diffusion coefficients for models trained with molecular dynamics and ERBS data. Further, we active-learn models for liquid water with and without enhanced sampling and compare the quality of simulated self-diffusion coefficients. The self-diffusion coefficients closely match those simulated with a reference model at a significantly reduced dataset size. Finally, we compare the sampling behaviour of enhanced sampling methods by benchmarking the mean squared displacements of \ce{BMIM+BF4-} trajectories simulated with uncertainty-driven dynamics and ERBS and find that the latter significantly increases the exploration of configurational space.
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https://arxiv.org/abs/2601.16047
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f98e0af0008fb234b906353e25dff9f8ce10829e342fcbd5f2371a693f62b335
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2026-01-23T00:00:00-05:00
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Gain-Layer Project
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arXiv:2601.16049v1 Announce Type: new Abstract: Gain-layer degradation from exposure to radiation limits the use of Low-Gain Avalanche Diodes (LGADs) in high energy particle physics detector experiments. Proper understanding of how the gain-layer is destroyed is not available on a defect level. Only measurements for materials with much lower effective doping concentrations are available. The direct study of the gain-layer is not possible with typical defect spectroscopy measurements like Thermally Stimulated Currents (TSC) and Deep-Level Transient Spectroscopy (DLTS). To combat this problem and gain a better understanding of the processes which degrade LGADs, the Gain-Layer Project was started. This project produced 19050 diodes with various Boron, Phosphorus, Oxygen and Carbon concentrations. The material used is low-resistivity p-type Silicon. The effective doping concentrations are in the order of a LGAD gain-layer. These diodes will serve the defect community in the coming years for various studies. This article introduces this project with detailed descriptions of the diodes, their flavours and their processing, and reports on results from I-V, C-V, SIMS and DLTS measurements on unirradiated diodes.
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https://arxiv.org/abs/2601.16049
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defd84f06adc14dc03afb8a9c222544164536c15233e19fe2737833c93588950
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2026-01-23T00:00:00-05:00
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Physics-Informed Neural Networks for Viscoacoustic Wave Propagation: Forward Modelling, Inversion and Discretization Sensitivity
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arXiv:2601.16068v1 Announce Type: new Abstract: Seismic wave forward and inverse modeling are fundamental tools for subsurface imaging and geological hazard assessment. Conventional grid-based numerical methods, such as finite-difference and finite-element approaches, often require dense discretization and repeated forward simulations, leading to high computational cost in inverse problems. Although deep learning has shown promise in seismic applications, its performance is commonly limited by the need for large labeled datasets and weak enforcement of physical constraints. In this study, we propose a unified physics-informed neural network (PINN) framework for forward modeling and parameter inversion of viscoacoustic wave propagation. By embedding the viscoacoustic wave equation into the learning process, the proposed framework accurately reproduces wavefields, attenuation, and phase characteristics, while enabling the simultaneous inversion of velocity and attenuation parameters from temporally sparse observations. Numerical experiments demonstrate that the PINN approach achieves stable and reliable accuracy compared with finite-difference solutions, while exhibiting reduced sensitivity to spatial discretization. These results highlight the potential of PINNs as a data-efficient and physically consistent alternative for high-resolution seismic modeling and inversion in attenuative media.
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https://arxiv.org/abs/2601.16068
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594bc82557e4ab67d76bc7308947468612f500b60160fbb6fac42fcad7da9551
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2026-01-23T00:00:00-05:00
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In vitro binding energies capture Klf4 occupancy across the human genome
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arXiv:2601.16151v1 Announce Type: new Abstract: Transcription factors (TFs) regulate gene expression by binding to specific genomic loci determined by DNA sequence. Their sequence specificity is commonly summarized by a consensus binding motif. However, eukaryotic genomes contain billions of low-affinity DNA sequences to which TFs associate with a sequence-dependent binding energy. We currently lack insight into how the genomic sequence defines this spectrum of binding energies and the resulting pattern of TF localization. Here, we set out to obtain a quantitative understanding of sequence-dependent TF binding to both motif and non-motif sequences. We achieve this by first pursuing accurate measurements of physical binding energies of the human TF Klf4 to a library of short DNA sequences in a fluorescence-anisotropy-based bulk competitive binding assay. Second, we show that the highly non-linear sequence dependence of Klf4 binding energies can be captured by combining a linear model of binding energies with an Ising model of the coupled recognition of nucleotides by a TF. We find that this statistical mechanics model parametrized by our in vitro measurements captures Klf4 binding patterns on individual long DNA molecules stretched in the optical tweezer, and is predictive for Klf4 occupancy across the entire human genome without additional fit parameters.
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https://arxiv.org/abs/2601.16151
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605ab436c5cc636c2da0819991d6527fb7ad6c3cacc7d586b5aba0767ef039a6
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2026-01-23T00:00:00-05:00
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Engineering polarization: How contradictory stimulation systematically undermines political moderation
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arXiv:2601.16181v1 Announce Type: new Abstract: Political moderation, a key attractor in democratic systems, proves highly fragile under realistic information conditions. We develop a stochastic model of opinion dynamics to analyze how noise and differential susceptibility reshape the political spectrum. Extending Marvel et al.'s deterministic framework, we incorporate stochastic media influence $\zeta(t)$ and neuropolitically-grounded sensitivity differences ($\sigma_y > \sigma_x$). Analysis reveals the moderate population -- stable in deterministic models -- undergoes catastrophic collapse under stochastic forcing. This occurs through an effective deradicalization asymmetry ($u_{B}^{\text{eff}} = u + \sigma_y^2/2 > u_{A}^{\text{eff}}$) that drives conservatives to extinction, eliminating cross-cutting interactions that sustain moderates. The system exhibits a phase transition from multi-stable coexistence to liberal dominance, demonstrating how information flow architecture -- independent of content -- systematically dismantles the political center. Our findings reveal moderation as an emergent property highly vulnerable to stochastic perturbations in complex social systems.
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https://arxiv.org/abs/2601.16181
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be44fe28f77e4014ad358931c91d97a3084f71c21638adcd8106f5f389577dbc
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2026-01-23T00:00:00-05:00
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Pushing the limits of unconstrained machine-learned interatomic potentials
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arXiv:2601.16195v1 Announce Type: new Abstract: Machine-learned interatomic potentials (MLIPs) are increasingly used to replace computationally demanding electronic-structure calculations to model matter at the atomic scale. The most commonly used model architectures are constrained to fulfill a number of physical laws exactly, from geometric symmetries to energy conservation. Evidence is mounting that relaxing some of these constraints can be beneficial to the efficiency and (somewhat surprisingly) accuracy of MLIPs, even though care should be taken to avoid qualitative failures associated with the breaking of physical symmetries. Given the recent trend of \emph{scaling up} models to larger numbers of parameters and training samples, a very important question is how unconstrained MLIPs behave in this limit. Here we investigate this issue, showing that -- when trained on large datasets -- unconstrained models can be superior in accuracy and speed when compared to physically constrained models. We assess these models both in terms of benchmark accuracy and in terms of usability in practical scenarios, focusing on static simulation workflows such as geometry optimization and lattice dynamics. We conclude that accurate unconstrained models can be applied with confidence, especially since simple inference-time modifications can be used to recover observables that are consistent with the relevant physical symmetries.
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https://arxiv.org/abs/2601.16195
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7d940fe0e6dc04c6bd127c35350d50989abba081bf0856c5078dc6b0808f76a3
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2026-01-23T00:00:00-05:00
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Electron Transfer, Diabatic Couplings and Vibronic Energy Gaps in a Phase Space Framework
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arXiv:2601.16209v1 Announce Type: new Abstract: We investigate the well-known Shin-Metiu model for an electronic crossing, using both a standard Born-Huang (BH) framework and a novel phase space (PS) electronic Hamiltonian framework. We show that as long as we are not in the strongly nonadiabatic region, a phase space framework can obtain a relative error in vibrational energy gap which is consistently one order of magnitude smaller than what is found within a BH framework. In line with recent results showing that dynamics on one phase space surface can outperform dynamics on one Born-Oppenheimer surface, our results indicate that the same advantages should largely hold for curve crossings and dynamics on two or a handful of electronic surfaces, from which several implications can be surmised as far as the possibility of spin-dependent electron transfer dynamics.
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https://arxiv.org/abs/2601.16209
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bcd64ccd72cd8d564683ab489c444d31802e7e7c42d354cd3cb996a0f2a03a8f
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2026-01-23T00:00:00-05:00
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Cost scaling of MPS and TTNS simulations for 2D and 3D systems with area-law entanglement
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arXiv:2601.08132v1 Announce Type: cross Abstract: Tensor network states are an indispensable tool for the simulation of strongly correlated quantum many-body systems. In recent years, tree tensor network states (TTNS) have been successfully used for two-dimensional systems and to benchmark quantum simulation approaches for condensed matter, nuclear, and particle physics. In comparison to the more traditional approach based on matrix product states (MPS), the graph distance of physical degrees of freedom can be drastically reduced in TTNS. Surprisingly, it turns out that, for large systems in $D>1$ spatial dimensions, MPS simulations of low-energy states are nevertheless more efficient than TTNS simulations. With a focus on $D=2$ and 3, the scaling of computational costs for different boundary conditions is determined under the assumption that the system obeys an entanglement (log-)area law, implying that bond dimensions scale exponentially in the surface area of the associated subsystems.
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https://arxiv.org/abs/2601.08132
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cb73d89a8843364b5e3a0afbac46667ee311287a18fdd7f951203fcb32ae191a
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2026-01-23T00:00:00-05:00
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Effects of 2.45 GHz radiofrequency upon Leuconostoc mesenteroides Glucose-6-phosphate dehydrogenase enzymatic activity
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arXiv:2601.11382v1 Announce Type: cross Abstract: In this report we evaluate the effect in the enzyme activity of Glucose 6-phosphate Dehydrogenase from Leuconostoc mesenteroides by irradiation with 2.45 GHz radiofrequency at a power output of 0.1 W during a 91 h period. The results show that the RF irradiation preserves the activity of treated samples of this enzyme with respect to a non-treated sample that instead suffer an increased rate of activity loss. Our estimates indicate that the enzyme activation is due to a non-thermal effect. The results are consistent with reports about the effect of 2.45 GHz radiation upon other enzymatic systems.
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https://arxiv.org/abs/2601.11382
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06893eccefdc2e9c0380a676424bb7cfdbd9d9d3ac8eda20fae047d3719aabf5
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2026-01-23T00:00:00-05:00
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Controlling HER activity and stability of $\gamma$- and 6,6,12-Graphyne through engineered B-N doping: DFT and Reactive MD simulations
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arXiv:2601.15424v1 Announce Type: cross Abstract: Graphynes offer a chemically heterogeneous $sp/sp^{2}$ carbon framework with distinct electronic regimes and site-selective reactivity. Here, Density Functional Theory and Reactive Molecular Dynamics Simulations are combined to evaluate pristine, B-doped, N-doped, and B-N co-doped $\gamma$-graphyne and 6,6,12-graphyne (meta/ortho/para). $\gamma$-graphyne is a semiconductor, while 6,6,12-graphyne exhibits an anisotropic Dirac-like semi-metallic dispersion. B/N substitution reconstructs near-$E_F$ states via dopant $\pi$ hybridization, and B-N pairing stabilizes defects through donor-acceptor compensation, with the ortho substitutions being the most favorable. Hydrogen adsorption remains weak on pristine lattices but becomes locally optimized upon doping, with near thermo-neutral $\Delta G_{\mathrm{ads}}$ 'hot spots' predominantly on $sp$-proximate carbon sites adjacent to the dopants. Reactive MD at 300 K further reveals an activity stability trade-off: B-N ortho in $\gamma$-graphyne sustains controlled hydrogen uptake without catastrophic bond scission, whereas B-N meta/para degrade, and 6,6,12-graphyne is generally more susceptible to over-hydrogenation. These results identify the B-N geometry as a key design variable for graphyne-based HER catalysts, which require both a favorable $\Delta G_{\mathrm{ads}}$ and finite-temperature hydrogenation stability.
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https://arxiv.org/abs/2601.15424
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1a14a5257a725fb2db26add3c9ba26de3310755b1b4a8dd32110a1daaa339c9b
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2026-01-23T00:00:00-05:00
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Numba-Accelerated 2D Diffusion-Limited Aggregation: Implementation and Fractal Characterization
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arXiv:2601.15440v1 Announce Type: cross Abstract: We present dla-ideal-solver, a high-performance framework for simulating two-dimensional Diffusion-Limited Aggregation (DLA) using Numba-accelerated Python. By leveraging just-in-time (JIT) compilation, we achieve computational throughput comparable to legacy static implementations while retaining high-level flexibility. We investigate the Laplacian growth instability across varying injection geometries and walker concentrations. Our analysis confirms the robustness of the standard fractal dimension $D_f \approx 1.71$ for dilute regimes, consistent with the Witten-Sander universality class. However, we report a distinct crossover to Eden-like compact growth ($D_f \approx 1.87$) in high-density environments, attributed to the saturation of the screening length. Beyond standard mass-radius scaling, we employ generalized R\'{e}nyi dimensions and lacunarity metrics to quantify the monofractal character and spatial heterogeneity of the aggregates. This work establishes a reproducible, open-source testbed for exploring phase transitions in non-equilibrium statistical mechanics.
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https://arxiv.org/abs/2601.15440
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3efb5a2b93bfd1c587637ad14fd98e7a8160370c0ce45716c5353f2bd865b723
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2026-01-23T00:00:00-05:00
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Bidirectional teleportation using scrambling dynamics: a practical protocol
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arXiv:2601.15536v1 Announce Type: cross Abstract: We show that quantum information scrambling can enable a generic SWAP gate between collective degrees of freedom in systems without universal local control. Our protocol combines the Hayden-Preskill recovery scheme, associated with the black hole information paradox, with quantum teleportation and runs them in parallel and in opposite directions, enabling bidirectional exchange of quantum states through global interactions alone. This approach cleanly distinguishes the roles of information spreading, entanglement, and chaos for enabling both coherent state transfer and recovery. We propose an experimental realization using the Dicke model, which can be realized in cavity-QED and trapped-ion platforms, highlighting the utility of holography in designing practical quantum gates.
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https://arxiv.org/abs/2601.15536
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c931a209b940f3e2ce7aefaa2979e36da53b491f254326a045bef62104bd4409
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2026-01-23T00:00:00-05:00
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Bright Pulsed Squeezed Light for Quantum-Enhanced Precision Microscopy
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arXiv:2601.15565v1 Announce Type: cross Abstract: Squeezed states of light enable enhanced measurement precision by reducing noise below the standard quantum limit. A key application of squeezed light is nonlinear microscopy, where state-of-the-art performance is limited by photodamage and quantum-limited noise. Such microscopes require bright, pulsed light for optimal operation, yet generating and detecting bright pulsed squeezing at high levels remains challenging. In this work, we present an efficient technique to generate high levels of bright picosecond pulsed squeezed light using a $\chi^2$ optical parametric amplification process in a waveguide. We measure $-3.2~\mathrm{dB}$ of bright squeezing with optical power compatible with nonlinear microscopy, as well as $-3.6~\mathrm{dB}$ of vacuum squeezing. Corrected for losses, these squeezing levels correspond to $-15.4^{+2.7}_{-8.7}~\mathrm{dB}$ of squeezing generated in the waveguide. The measured level of bright amplitude pulsed squeezing is to our knowledge the highest reported to date, and will contribute to the broader adoption of quantum-enhanced nonlinear microscopy in biological studies.
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https://arxiv.org/abs/2601.15565
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8ec9934bd37b118a8b49ba2dc3f6adcedf096f3a623506204d9d752721ded9ce
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2026-01-23T00:00:00-05:00
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Anomalous valley Hall dynamics of exciton-polaritons
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arXiv:2601.15631v1 Announce Type: cross Abstract: The valley degree of freedom in atomically thin transition-metal dichalcogenides provides a natural binary index for information processing. Exciton-polaritons formed under strong light-matter coupling offer a promising route to overcome the limited lifetime and transport of bare valley excitons. Here we report an anomalous optical valley Hall effect in a monolayer WS2 exciton-polariton system. Using polarization- and time-resolved real-space imaging, we directly visualize a symmetry-breaking spatial separation of polaritons from opposite valleys under linearly polarized excitation, accompanied by an ultrafast Hall drift velocity on the order of 10^5 m/s. This behaviour cannot be accounted for by conventional cavity-induced mechanisms and instead points to a strain-induced synthetic pseudomagnetic field acting on the excitonic component of polaritons. Our results establish exciton-polaritons as a high-speed and optically accessible platform for valley transport, opening pathways towards tunable valleytronic and topological photonic devices.
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https://arxiv.org/abs/2601.15631
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b1a1fe7d3727215f7c6f29c9e78a15d86b2c8e53ab53ef2c500128e6198a163a
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2026-01-23T00:00:00-05:00
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Enhancing the Size of Phase-Space States Containing Sub-Planck-Scale Structures via Non-Gaussian Operations
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arXiv:2601.15654v1 Announce Type: cross Abstract: We observe a metrological advantage in phase-space sensitivity for photon-added cat and kitten states over their original forms, due to phase-space broadening from increased amplitude via photon addition, albeit with higher energy cost. Using accessible non-classical resources, weak squeezing and displacement, we construct a squeezed state and two superposed states: the squeezed cat state and the symmetrically squeezed state. Their photon-added variants are compared with parity-matched cat and KSs using quantum Fisher information and fidelity. The QFI isocontours reveal regimes where KS exhibit high fidelity and large amplitude, enabling their preparation via Gaussian operations and photon addition. Similar regimes are identified for cat states enhanced by squeezing and photon addition, demonstrating improved metrological performance. Moreover, increased amplitude and thus larger phase-space area reduces the size of interferometric fringes, enhancing the effectiveness of quantum error correction in cat codes.
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https://arxiv.org/abs/2601.15654
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fcce64f23e7f608cc5a776dd67722054fd6534884a17300bd0b8855395916361
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2026-01-23T00:00:00-05:00
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Emergence of spatiotemporal patterns in a fuel-driven coupled cooperative supramolecular system
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arXiv:2601.15662v1 Announce Type: cross Abstract: Chemically fueled supramolecular systems can exhibit complex, time-dependent behaviors reminiscent of living matter when maintained far from equilibrium by continuous energy or fuel consumption. Here, we introduce a minimal reaction-diffusion model that captures the essential dynamics of a cooperative supramolecular polymerization network driven by monomer activation and deactivation. We show that a balance between autocatalytic growth and inhibitory decay sustains a nonequilibrium steady state in the model that undergoes a Hopf bifurcation, giving rise to autonomous oscillations. When spatial transport is introduced through diffusion, the system displays rich spatiotemporal phenomena, such as traveling wavefronts and transient polygonal patterns. Our results demonstrate that the interplay between reaction kinetics and diffusion can spontaneously generate self-organized, life-like dynamics in synthetic supramolecular polymer systems. This theoretical framework not only bridges molecular self-assembly and active matter dynamics but also provides design principles for creating adaptive, oscillatory, and self-patterning materials powered by chemical fuels.
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https://arxiv.org/abs/2601.15662
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0f407cc39fcaddc7b0237fbf95df4c6775186ef27d0962fc8ae167cb153d1e1c
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2026-01-23T00:00:00-05:00
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Distance-Independent Atmospheric Refraction Correction for Accurate Retrieval of Fireball Trajectories
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arXiv:2601.15805v1 Announce Type: cross Abstract: Accurate determination of fireball direction is essential for retrieving trajectories and velocities. Errors in these measurements have significant implications, affecting the calculated pre-impact orbit, influencing mass estimates, and impacting the accuracy of dark flight simulations, where applicable. Here we implement a new atmospheric refraction correction technique that addresses a significant aspect previously overlooked in the field of meteor science. Traditional refraction correction techniques, originally designed for objects positioned at infinite distances, tend to overcompensate when applied to objects within the Earth's atmosphere. To rectify this issue, our study introduces the concept of the atmospheric refraction delta z correction technique, involving the artificial elevation of the observer site height above sea level. We utilize analytically derived formulas for the delta z correction in conjunction with commonly used refraction models, validating these results against a numerical solution that traces light rays through the atmosphere. This ray-tracing model is applied to finely meshed atmospheric layers, yielding precise correction values. We evaluate multiple sources of error in order to quantify the achievable accuracy of the proposed method. Our approach (1) enables the determination of fireball positions with improved astrometric accuracy, (2) removes the explicit dependence on the fireball distance from the observer or its height above Earth's surface within the limits imposed by realistic atmospheric variability, and (3) simplifies meteor data processing by providing a robust framework for analyzing low-elevation fireball observations, for which atmospheric refraction is significant and is automatically corrected by the method. As a result of this work, we provide open, publicly accessible software for calculating the delta z correction.
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https://arxiv.org/abs/2601.15805
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97a2d2c0ddf8440d132bda5ce645422a28daf46785e9abe537d7aac08c25dceb
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2026-01-23T00:00:00-05:00
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Muon beams towards muonium physics: progress and prospects
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arXiv:2601.15818v1 Announce Type: cross Abstract: Advances in accelerator technology have led to significant improvements in the quality of muon beams over the past decades. Investigations of the muon and muonium enable precise measurements of fundamental constants, as well as searching for new physics beyond the Standard Model. Furthermore, by utilizing muon beams with high intensity and polarization, studies of the dynamics of the muon and muonium within atom level can offer valuable insights into material science. This review presents recent progress and prospects at the frontiers of muon beams and high-precision muonium physics. It also provides an overview of novel methods and detection techniques to achieve high sensitivities in different areas, including particle physics, nuclear physics, materials science and beyond.
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https://arxiv.org/abs/2601.15818
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e9debbc47d67bb680de9d2ee3dc6221bf88e71e68697195ee9b62cdf59822daa
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2026-01-23T00:00:00-05:00
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Effects of pulsed and continuous light and heavy ion irradiation on the morphology and electrical properties of Ag+C60 and Au+C60 composite thin films
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arXiv:2601.15835v1 Announce Type: cross Abstract: Metal - organic nanocomposite thin films represent a versatile class of materials whose properties can be effectively tuned through external stimuli. In this study, Ag+C60 and Au+C60 nanocomposite thin films were briefly investigated to elucidate the effects of ion irradiation on both their morphology and electrical properties. The films were synthesized by co-deposition of noble metals and fullerenes, using ion beam sputtering of metal targets combined with simultaneous thermal evaporation of C60. The as - deposited films were characterized by ion beam analysis to determine their composition and element depth distributions. Subsequently, the samples were irradiated at room temperature with either a continuous Ar ion beam or a pulsed C ion beam, both at an energy of 20 keV and a fluence of 1 x 1015 ions/cm2. Irradiation-induced morphological changes were examined by scanning electron microscopy. While the C-irradiated films retained compact and homogeneous surface morphologies, Ar irradiation induced pronounced surface restructuring, resulting in highly corrugated and porous-like surfaces. In addition to morphology, the electrical resistance of the films was measured. The results indicate that C-irradiated samples exhibit only minor changes in resistivity, whereas Ar irradiation strongly affects the electrical properties, with the most significant impact observed for the Au+C60 system. The observed changes in electrical resistance closely correlate with the irradiation-induced surface morphology. The measurement results are briefly discussed below.
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https://arxiv.org/abs/2601.15835
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d7b9f58e7d15650d96d27b69a0d24a99f97456bde24b2dcdd380d157b6962f2a
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2026-01-23T00:00:00-05:00
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Reaching the intrinsic performance limits of superconducting strip photon detectors up to 0.1 mm wide
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arXiv:2601.15971v1 Announce Type: cross Abstract: Superconducting nanowire single-photon detectors (SNSPDs) have emerged as the highest performing photon-counting detectors, making them a critical technology in quantum photonics and photon-starved optical sensing. However, the performance of SNSPDs is limited not by the intrinsic properties of the superconducting film, but by edge-induced current crowding. Despite extensive materials optimization and increasingly demanding fabrication strategies aimed at mitigating this edge-limited behavior, the device edges continue to limit the maximum device operating current, thereby degrading key performance metrics. Here, we demonstrate for the first time in situ tuning of a detector from an edge-limited to a bulk-limited regime, allowing the device to reach its intrinsic performance limit. Our approach is based on current-biased superconducting "rails" placed on either side of the detector to suppress current crowding at the edges. We show that activation of the rails reduces the dark count rate by nine orders of magnitude and extends the photon detection plateau at 1550 nm by more than 40%. These results are demonstrated on detectors up to 0.1 mm wide, establishing an entirely new class of ultra-wide strip detectors that we call superconducting strip photon detectors (SSPD). Moreover, the ability to suppress edge current crowding using the rails provides a pathway toward SSPDs with strip widths extending into the mm-scale. Such devices will enable large-area, high efficiency SSPD arrays with infrared sensitivity and open new opportunities in applications ranging from biomedical imaging to deep space optical communication.
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https://arxiv.org/abs/2601.15971
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ae11c2d477388522775a7b9f11afbd0752d6101dd61afec32fd04adfdfaa8184
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2026-01-23T00:00:00-05:00
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Real-Time Inviscid Fluid Dynamics and Aero-acoustics on a Sphere
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arXiv:2601.15982v1 Announce Type: cross Abstract: Real-time fluid and aeroacoustic simulation on complex surfaces can have interactive applications - from globe-based weather visualizations to immersive computer games with physically accurate wind and sound. However, conventional grid-based solvers struggle with numerical instability near surface singularities, and mesh-based approaches lack a straightforward path to solving partial differential equations (PDEs) with stable, high-order accuracy. Our model presents a unified framework for real-time inviscid fluid simulation and aeroacoustics on spherical surfaces with embedded obstacles, combining the Closest Point Method (CPM), projection-based Navier-Stokes solvers, and the Ffowcs Williams-Hawkings (FWH) analogy. CPM enables surface PDEs to be solved in a Cartesian embedding without parametrization by restricting computation to a narrow band around the sphere. Each band point is mapped to its nearest surface location, where band operators project results onto the local tangent space. Surface obstacles are modelled with signed distance functions (SDFs), enforcing no-slip velocity constraints and Bernoulli-based pressure adjustments for consistent real-world boundary interactions. Aeroacoustic sources are computed directly from surface pressure force derivatives and mapped to real-time audio via frequency and amplitude modulation with artifact-suppressing hysteresis smoothing. Our findings from this model simulate the behaviour of inviscid fluid on spherical surfaces while generating sound using the pressure of the fluid flowing on the surface. This approach gives results that offer stability, geometric consistency, and support applications in scientific visualization, virtual reality, and educational tools.
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https://arxiv.org/abs/2601.15982
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a791ee7ffe9f917b134242ec37d536d6d8ba5e3baa2985e7e4068bc23e21eb6b
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2026-01-23T00:00:00-05:00
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Critical speed of a binary superfuid of light
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arXiv:2601.16005v1 Announce Type: cross Abstract: We theoretically study the critical speed for superfluid flow of a two-dimensional (2D) binary superfluid of light past a polarization-sensitive optical obstacle. This speed corresponds to the maximum mean flow velocity below which dissipation is absent. In the weak-obstacle regime, linear-response theory shows that the critical speed is set by Landau's criterion applied to the density and spin Bogoliubov modes, whose relative ordering can be inverted due to saturation of the optical nonlinearity. For obstacles of arbitrary strength and large spatial extent, we determine the critical speed from the conditions for strong ellipticity of the stationary hydrodynamic equations within the hydraulic and incompressible approximations. Numerical simulations in this regime reveal that the breakdown of superfluidity is initiated by the nucleation of vortex-antivortex pairs for an impenetrable obstacle, and of Jones-Roberts soliton-type structures for a penetrable obstacle. Beyond superfluids of light, our results provide a general framework for the critical speed of 2D binary nonlinear Schr\"odinger superflows, including Bose-Bose quantum mixtures.
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https://arxiv.org/abs/2601.16005
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458e623a42d21502e1229029de46e00b7d783bd8dde6b3fb8049c582dd48bed0
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2026-01-23T00:00:00-05:00
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Random Walks Across Dimensions: Exploring Simplicial Complexes
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arXiv:2601.16086v1 Announce Type: cross Abstract: We introduce a novel operator to describe a random walk process on a simplicial complex. Walkers are allowed to wonder across simplices of various dimensions, bridging nodes to edges, and edges to triangles, via a nested organization that hierarchically extends to higher structures of arbitrary large, but finite, dimension. The asymptotic distribution of the walkers provides a natural ranking to gauge the relative importance of higher order simplices. Optimal search strategies in presence of stochastic teleportation are addressed and the peculiar interplay of noise with higher order structures unraveled.
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https://arxiv.org/abs/2601.16086
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b49ae2bc7ceb4c71cab3ed74fb70c6569e7b91d97b2a9e47456f8fe5ac770ff8
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2026-01-23T00:00:00-05:00
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Universal non-Gaussian order parameter statistics in 2D superfluids
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arXiv:2601.16204v1 Announce Type: cross Abstract: Fluctuations are an intrinsic feature of many-body systems, and their full statistical distributions reveal a wealth of information about the underlying physics. Of particular interest are non-Gaussian, extreme-value statistics that arise when nontrivial correlations and criticality dominate over the central limit theorem. Strikingly, in two-dimensional (2D) quantum fluids, such effects have been predicted to manifest in the order parameter distribution in the Berezinskii-Kosterlitz-Thouless (BKT) superfluid phase, which approaches a universal extreme-value form in the low-temperature limit. Here, we measure the order parameter statistics of 2D Bose gases across the BKT critical point using matter-wave interferometry. This allows us to confirm the predicted convergence of the observed statistics to a universal Gumbel distribution at low temperatures, to the 0.1% level of the probability density. Furthermore, the intrinsic precision of the atom interferometer allows the robust extraction of higher-moment observables such as skewness and kurtosis; in particular, we report direct measurements of the Binder cumulant which allows us to precisely identify the onset of the phase transition. Extending this approach to the investigation of non-equilibrium systems, we probe vortex unbinding dynamics following a quench across the BKT critical point and identify parameter-independent scaling behaviour of higher moments.
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https://arxiv.org/abs/2601.16204
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caf42b0f1647215bff25b36f20c9fe8a46ae924fe5994197432ace4f13dd18df
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2026-01-23T00:00:00-05:00
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Light-induced, fictitious magnetic trapping of cold alkali atoms using an optical tweezers-nanofiber hybrid platform
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arXiv:2412.04809v4 Announce Type: replace Abstract: We present a magnetic trapping scheme for cold 87Rb atoms based on light-induced fictitious magnetic fields generated by the evanescent field of an optical nanofiber (ONF) integrated with an optical tweezers. We calculate and compare the trapping potentials for both Gaussian and Laguerre-Gaussian modes of the tweezers beam, combined with a quasi-linearly polarized ONF-guided field. Based on the optical powers in the tweezers and ONF modes, we analyze the trap depths and the positions of the potential minima from the nanofiber surface. We show that, by varying the optical powers in the two fields, the trap position can be tuned over several hundred nanometers, while simultaneously influencing the trap depth and trap frequencies. Such control over atom-surface position is essential for studying distance-dependent effects on atoms trapped near a dielectric surface and optimizing atom-photon interfaces for quantum technology applications.
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https://arxiv.org/abs/2412.04809
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f8c4c3503f7391dd13fce47cff5a09b25fac1de7f667089fab748ff36d4b975e
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2026-01-23T00:00:00-05:00
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Meshless Super-Resolution of Scattered Data via constrained RBFs and KNN-Driven Densification
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arXiv:2503.04630v3 Announce Type: replace Abstract: We propose a novel meshless method to achieve super resolution from scattered data obtained from sparse, randomly positioned sensors such as the particle tracers of particle tracking velocimetry. The method combines K Nearest Neighbor Particle Tracking Velocimetry (KNN PTV, Tirelli et al. 2023) with meshless Proper Orthogonal Decomposition (meshless POD, Tirelli et al. 2025) and constrained Radial Basis Function regression (c RBFs, Sperotto et al. 2022). The main idea is to enhance the spatial resolution of flow fields by blending data from locally similar flow regions available in the time series. This similarity is assessed in terms of statistical coherency with leading features identified by meshless POD applied directly to scattered data, without interpolation onto a grid and relying instead on RBFs to compute the relevant inner products. The denser scattered distributions are then used within a constrained RBF framework to derive an analytical representation of the flow fields that incorporates physical constraints. The approach is fully meshless and does not require a grid at any stage, offering flexibility in complex geometries. An ablation study highlights the role of penalties and physical constraints in regularizing the regression and ensuring physically consistent reconstructions. The method is validated using three dimensional measurements of a jet flow in air. The assessment focuses on statistics, spectra, and modal analysis. Performance is evaluated against standard Particle Image Velocimetry, KNN PTV, and c RBFs. The results show improved accuracy, with an average error of about ten percent compared to twelve to thirteen percent for the other methods, nearly halved errors in reduced order reconstructions, and a higher frequency cutoff based on the noise floor.
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https://arxiv.org/abs/2503.04630
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3ba075a08bf06dcb402f5f202de057328d261ea16599c5e94b49bb96f52518aa
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2026-01-23T00:00:00-05:00
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Picogram-Level Nanoplastic Analysis with Nanoelectromechanical System Fourier Transform Infrared Spectroscopy: NEMS-FTIR
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arXiv:2504.10192v3 Announce Type: replace Abstract: We present a photothermal infrared spectroscopy-based approach for the chemical characterization and quantification of nanoplastics. By combining the high sensitivity of nanoelectromechanical systems (NEMS) with the wide spectral range and ubiquity of commercially available Fourier transform infrared (FTIR) spectrometers, NEMS-FTIR offers a time-efficient and cryogen-free option for the rapid, routine analysis of nanoplastics in aqueous samples. Polypropylene, polystyrene, and polyvinyl chloride nanoplastics with nominal diameters ranging from 54 to 262 nm were analyzed by NEMS-FTIR with limits of detection ranging from 101 pg to 353 pg, one order of magnitude lower than values reported for pyrolysis-gas chromatography-mass spectrometry of nanoplastics. The absorptance measured by NEMS-FTIR could be further converted to absolute sample mass using the attenuation coefficient, as demonstrated for polystyrene. Thanks to the wide spectral range of NEMS-FTIR, nanoplastic particles from different polymers could be readily identified, even when present in a mixture. The potential of NEMS-FTIR for the analysis of real samples was demonstrated by identifying the presence of nanoplastics released in water during tea brewing. Polyamide leachates in the form of fragments and smaller oligomers could be identified in the brewing water without sample pre-concentration, even in the presence of an organic matrix. Accelerated aging of the nylon teabags under elevated temperature and UV radiation showed further release of polyamide over time.
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https://arxiv.org/abs/2504.10192
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a934da93b166c485aebab9bc78e8d9be356e53f6ca20ab8afa9985de7f1e6372
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2026-01-23T00:00:00-05:00
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Spin-Orbit Coupling in Helical Waveguides: A Local Duality Perspective and Emergent Gauge Fields
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arXiv:2504.19501v4 Announce Type: replace Abstract: Dual symmetry is an intrinsic property of Maxwell's equations, corresponding to a global U(1) symmetry in vacuum, with helicity as the associated conserved quantity. In this paper, we investigate light propagation in a spin-degenerate medium using a field-theoretical approach and introduce an effective gauge field A_s that emerges from the localization of dual symmetry. Within the geometric optics approximation, we show that the helical trajectory of light rays reveals this gauge field as a manifestation of spin-orbit coupling. Although orbital-orbit coupling also arises in such systems, the spin-orbit interaction possesses deeper physical significance, as it originates from the intrinsic dual symmetry embedded in Maxwell's equations.
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https://arxiv.org/abs/2504.19501
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b38caf9c79eb44f45f480a3819b24eb1719103ef1814d38087eb98a38414e026
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2026-01-23T00:00:00-05:00
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Fast recovery of parametric eigenvalues depending on several parameters and location of high order exceptional points
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arXiv:2505.06141v2 Announce Type: replace Abstract: A numerical algorithm is proposed to deal with parametric eigenvalue problems involving non-Hermitian matrices and is exploited to find location of defective eigenvalues in the parameter space of non-Hermitian parametric eigenvalue problems. These non-Hermitian degeneracies also called exceptional points (EP) have raised considerable attention in the scientific community as these can have a great impact in a variety of physical problems. The method first requires the computation of high order derivatives of a few selected eigenvalues with respect to each parameter involved. The second step is to recombine these quantities to form new coefficients associated with a partial characteristic polynomial (PCP). By construction, these coefficients are regular functions in a large domain of the parameter space which means that the PCP allows one to recover the selected eigenvalues as well as the localization of high order EPs by simply using standard root-finding algorithms. The versatility of the proposed approach is tested on several applications, from mass-spring systems to guided acoustic waves with absorbing walls and room acoustics. The scalability of the method to large sparse matrices arising from conventional discretization techniques such as the finite element method is demonstrated. The proposed approach can be extended to a large number of applications where EPs play an important role in quantum mechanics, optics and photonics or in mechanical engineering.
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https://arxiv.org/abs/2505.06141
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08c5a5928818e3f1bad450e98d1cbbe79540df8ef6a5c8064af542f9170fa329
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2026-01-23T00:00:00-05:00
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Pulsation of Burner-Stabilized CH4-O2 Flames Moderated by CO2 Addition
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arXiv:2507.10905v4 Announce Type: replace Abstract: This study investigated the pulsating instability of burner-stabilized premixed CH4-O2 flames at various levels of CO2 dilution. Experiments were conducted using a water-cooled porous-plug burner of 18 mm diameter over a wide range of mixture compositions and flow rates, during which time-resolved measurements of flame chemiluminescence and gas temperature were obtained. The primary oscillation frequencies of the pulsating flames were determined using fast Fourier transform and harmonic power analysis. Phase-locked analysis of the chemiluminescence images revealed an interesting mode-transition phenomenon of the flame oscillations. Under fuel-rich conditions with relatively low heat release rates and low flow rates, the flames exhibited quasi-periodic single-mode oscillations. At elevated flow rates, these oscillations were modulated by low-frequency flame flickering instabilities, which created sidebands around the primary oscillation frequency. At higher heat release rates, the flickering instability further triggered mode splitting, eventually leading to multi-mode oscillations. Regime diagrams of the flame oscillation modes, as well as the stability boundaries, were obtained under various fuel flow rates. These findings can be useful for both fundamental research on flame dynamics and practical applications of CO2-moderated oxy-combustion.
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https://arxiv.org/abs/2507.10905
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e34136d16f1ee7063e70ac71bb9035611302073eb3f10e87f28768dda36b1e99
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2026-01-23T00:00:00-05:00
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Adaptive optics design for high-energy kW-class multi-slab laser amplifier
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arXiv:2508.02259v3 Announce Type: replace Abstract: We demonstrate real-time wavefront correction in a high-energy high-average-power DiPOLE100/Bivoj laser using adaptive optics. A bimorph deformable mirror and Shack-Hartmann wavefront sensor reduced wavefront error tenfold and improved the Strehl ratio elevenfold. Design aspects such as deformable mirror actuator geometry, optimal placement, and loop frequency are discussed for integration into next-generation high-energy high-average-power lasers.
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https://arxiv.org/abs/2508.02259
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7a2c2905d48412b55d55424ab1157b859bb2454030eaa4a02cba0f51433fcc21
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2026-01-23T00:00:00-05:00
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Studying magnetic circular vortex dichroism effect for photoionization of Rydberg atoms with vortex photons
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arXiv:2509.06603v2 Announce Type: replace Abstract: Rydberg atoms, renowned for their exceptional quantum properties, hold significant importance in quantum physics. The photoionization of Rydberg atoms serves as a critical tool for probing their unique characteristics. In this work, we investigate the photoionization dynamics of hydrogen-like Rydberg alkali atoms interacting with vortex photons-a class of structured light carrying intrinsic orbital angular momentum. This process gives rise to novel quantum phenomena distinct from conventional photoionization processes. Our results reveal that vortex photons exhibit exceptional sensitivity to the magnetic moments of Rydberg atoms, positioning them as a powerful spectroscopic tool for investigating Rydberg magnetism. It is also demonstrated that the initial photon energy must be carefully selected to observe significant experimental results. Furthermore, the photoionization process displays strong angular momentum selectivity, preferentially favoring configurations where the photon total angular momentum and atomic magnetic moment are aligned. This pronounced asymmetry directly manifests the chiral nature of the vortex photon-Rydberg atom collisions.
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https://arxiv.org/abs/2509.06603
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4c9c4a5817456e25df7ebde37f9dd8f9f27021327ca9e7b8e33f9d3ec253f707
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2026-01-23T00:00:00-05:00
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Shortest-path percolation on scale-free networks
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arXiv:2509.09142v2 Announce Type: replace Abstract: The shortest-path percolation (SPP) model aims at describing the consumption and eventual exhaustion of a network's resources. Starting from a network containing a macroscopic connected component, random pairs of nodes are sequentially selected, and if the length of the shortest path connecting the node pairs is smaller than a tunable budget parameter, then all edges along such a path are removed from the network. As edges are progressively removed, the network eventually breaks into multiple microscopic components, undergoing a percolation-like transition. It is known that SPP transition on Erd\H{o}s-R\'enyi networks (ERNs) belongs to same universality class as of the ordinary bond percolation if the budget parameter is finite; for unbounded budget, instead, the SPP transition becomes more abrupt than the ordinary percolation transition. By means of large-scale numerical simulations and finite-size scaling analysis, here we study the SPP transition on random scale-free networks (SFNs) characterized by power-law degree distributions. We find, in contrast with ordinary percolation, that the transition is identical to the one observed on ERNs, denoting independence from the degree exponent. Still, we distinguish finite- and infinite-budget SPP universality classes. Our findings follow from the fact that the SPP process drastically homogenizes the heterogeneous structure of SFNs before the SPP transition takes place.
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https://arxiv.org/abs/2509.09142
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bfc993f1d50c64cb61aaf0c6bda9a6c49c06ea7571949040e6bb8010f33b0c07
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2026-01-23T00:00:00-05:00
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Asymptotics of spherical dynamos exhibiting a small-scale MAC balance
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arXiv:2509.21348v3 Announce Type: replace Abstract: Understanding the asymptotic behaviour of numerical dynamo models is critical for extrapolating results to the physical conditions that characterise terrestrial planetary cores. Here we investigate the behaviour of convection-driven dynamos reaching a MAC (magnetic-Archimedes-Coriolis) balance on the convective length scale and compare the results with non-magnetic convection cases. In particular, the dependence of physical quantities on the Ekman number, $Ek$, is studied in detail. The scaling of velocity dependent quantities is observed to be independent of the force balance and in agreement with quasi-geostrophic theory. The primary difference between dynamo and non-magnetic cases is that the fluctuating temperature is order unity in the former such that the buoyancy force scales with the Coriolis force. The MAC state yields a scaling for the flow speeds that is identical to the so-called CIA (Coriolis-inertia-Archimedes) scaling. There is an $O(Ek^{1/3})$ length scale present within the velocity field irrespective of the leading order force balance. This length scale is consistent with the asymptotic scaling of the terms of the governing equations and is not an indication that viscosity plays a dominant role. The peak of the kinetic energy spectrum and the ohmic dissipation length scale both exhibit an Ekman number dependence of approximately $Ek^{1/6}$, which is consistent with a scaling of $Rm^{-1/2}$, where $Rm$ is the magnetic Reynolds number. For the dynamos, advection remains comparable to, and scales similarly with, both inertia and viscosity, implying that nonlinear convective Rossby waves play an important role in the dynamics even in a MAC regime.
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https://arxiv.org/abs/2509.21348
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ec6d0d1ec23e7c5eb45231e0f45c8ea1831e719baf6ed465bab2ccd969dc3fec
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2026-01-23T00:00:00-05:00
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Phase stabilization for long baseline interferometry of incoherent optical sources
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arXiv:2510.13263v2 Announce Type: replace Abstract: The maximum baseline, and therefore resolution, of optical astronomical interferometers is limited by attenuation and phase noise within the optical path between the apertures and beam combiner, as well as the practical challenges of constructing optical delay lines more than a few hundred meters in length. We implement off-band phase stabilization on two fiber optic links of 85~km, creating a total baseline of 170~km. We show that the system is able to effectively phase stabilize signals from an incoherent pseudo-thermal source with a bandwidth of 11.2~nm. We are able to reduce the phase noise by 4-5 orders of magnitude between 1 and 100~Hz such that we could resolve an applied phase difference of 0.16~cycles per second with continuous measurement. We show that, with phase stabilization active, the interferometer is able to recover both first-order and second-order photon correlations. These results demonstrate the feasibility of this technique for long-baseline optical and quantum astronomical interferometers. The present results are limited by chromatic dispersion within the fiber, which can be mitigated using dispersion compensating modules.
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https://arxiv.org/abs/2510.13263
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a29e490d6fc5aeaf4d8954cd0825d3dc0e1a780e64010f7df67916921d756987
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2026-01-23T00:00:00-05:00
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Multiphase modeling of anisotropic biomass particle pyrolysis accounting for particle deformation and coupled gas-phase dynamics
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arXiv:2510.17588v2 Announce Type: replace Abstract: Numerical models of biomass particle pyrolysis focus on either the solid particle evolution or on the surrounding gas-phase dynamics, neglecting the coupled interactions between the two. This work addresses this limitation by proposing a single-grid model that fully resolves both phases without relying on sub-grid-scale correlations. The model adopts an Eulerian representation of the two-phase system, using a Volume-Of-Fluid (VOF) method to track the interface between the biomass and the surrounding gas phase. Solid-phase pyrolysis reactions are included, and a novel approach is proposed to capture the coupling between the evolution of biomass porosity and the particle shrinkage, combining different biomass conversion models into one unique framework. The anisotropic nature of the biomass particle is accounted for in this multidimensional framework. The resulting model is independent of the number and shape of the particle, and demonstrates mass conservation and numerical convergence. Extensive validation with experimental data, collected from wood particles in the centimetre scale and operating temperature between 400-700{\deg}C, shows excellent agreement in terms of mass and temperature profiles and correct volatiles trends. Predicted char yields fall within 2% error range. Shrinking profiles reveal correct trends, with a 10% average error in the final particle shape, but they also highlight the need for a better fundamental understanding of the evolution of the biomass structure. Overall, the model takes a step forward in aiding the development of sustainable pyrolysis processes. The code and simulation setups, developed within the open-source Basilisk framework, are made publicly available.
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https://arxiv.org/abs/2510.17588
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af8a19bdd40bc959d7d4b6f88a1d1d775beacde4271eaef8c7961239ff89571c
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2026-01-23T00:00:00-05:00
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Boundary layer transition induced by surface roughness distributed over a low-pressure turbine blade
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arXiv:2510.22310v2 Announce Type: replace Abstract: Direct numerical simulations of a low-pressure turbine with roughness elements distributed over the blade surface have been performed. A series of fifteen cases with varying roughness heights and streamwise wavenumbers are introduced to present a systematic study of the effect of roughness on the various transition phenomena in the suction-side boundary layer. For cases with large roughness heights, the boundary layer is violently disturbed by the wake of rough elements in the leading edge (LE) region, and maintains the turbulent state over the whole blade suction-side. For cases with small roughness heights, however, the disturbances induced by the LE roughness are suppressed by the favourable pressure gradient in the downstream boundary layer, and the relaminarized flow does not undergo transition until the separation near the blade trailing edge (TE). Furthermore, the streamwise wavenumber of the distributed roughness plays an important role in cases with intermediate roughness height. Specifically, cases with larger streamwise slope show earlier transition induced by strong shear layer instability, which manages to suppress the mean flow separation near the TE region. Overall, the combined effect of several factors, including the geometric effect at the blade LE and TE, the complex pressure gradient distribution across the turbine vane, and the various roughness configurations, is responsible for the intriguing boundary layer behaviours in the present study.
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https://arxiv.org/abs/2510.22310
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a183abbc4d9333b453351fbeb90afdcdafc1fd400e0afdaba1747792c827e8f5
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2026-01-23T00:00:00-05:00
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Galvanometer-scanning transient phase microscopy with balanced detection and arbitrary pump polarization
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arXiv:2511.05443v2 Announce Type: replace Abstract: Transient absorption microscopy measures excited-state kinetics based on the imaginary part of the pump-induced perturbation to the complex refractive index, i.e. $\Im \{\Delta\mathcal N\}$, with applications in both materials and biomedical sciences. Its complement, transient phase microscopy, enabled by stable inline birefringent interferometry, measures the real part $\Re\{\Delta \mathcal N\}$. The ability to switch between absorption and phase measurements may yield a stronger signal, depending on the sample and probe wavelength. To date, however, transient phase has not been coupled with galvanometer scanners, thus limiting it to materials science applications and non-imaging spectroscopy. Here, we extend transient phase microscopy to operate in a galvanometer-scanning microscope with balanced detection, comparing amplitude and phase measurements in graphene (in which amplitude detection has the advantage), hemoglobin and red blood cells (in which phase detection has the advantage). We examine the impacts and limitations introduced by galvanometer scanning, in addition to relocation of the pump-probe combining dichroic to permit arbitrary polarization of the pump.
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https://arxiv.org/abs/2511.05443
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1ed8e3621f77a72a95519aa8e5e26b3c35a31e3fbdb587bf40d4b09bc8493af6
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2026-01-23T00:00:00-05:00
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Structural transitions induced by adaptive rewiring in networks with fixed states
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arXiv:2511.15043v2 Announce Type: replace Abstract: We investigate structural transitions in adaptive networks where node states remain fixed and only the connections evolve via state-dependent rewiring. Using a general framework characterized by probabilistic rules for disconnection and reconnection based on node similarity, we systematically explore how homophilic and heterophilic interactions influence network topology. A mean-field approximation for the stationary density of active links-those connecting nodes in different states-is developed to determine the conditions under which fragmentation occurs. Analytical results closely agree with numerical simulations. To distinguish community formation from fragmentation, we introduce order parameters that integrate modularity and connectivity. This enables the characterization of three distinct network phases on the rewiring parameter space: i) random connectivity, ii) community structure, and iii) fragmentation. Community structure emerges only under moderate homophily, while extreme homophily or heterophily lead to fragmentation or random networks, respectively. These findings demonstrate that adaptive rewiring alone, independent of node dynamics, can drive complex structural self-organization, with implications for social, technological, and ecological systems where node attributes are intrinsically stable.
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https://arxiv.org/abs/2511.15043
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7c2cad7372f7ecc93e21367b4fd5001a6d7f6d0e7acf1eb58866db9a2e035b29
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2026-01-23T00:00:00-05:00
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Implicit and explicit treatments of model error in numerical simulation
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arXiv:2511.15934v2 Announce Type: replace Abstract: Numerical simulations of physical systems exhibit discrepancies arising from unmodeled physics and idealizations, as well as numerical approximation errors stemming from discretization and solver tolerances. This article reviews techniques developed in the past several decades to approximate and account for model errors, both implicitly and explicitly. Beginning from fundamentals, we frame model error in inverse problems, data assimilation, and predictive modeling contexts. We then survey major approaches: the Bayesian approximation error framework, embedded internal error models for structural uncertainty, probabilistic numerical methods for discretization uncertainty, model discrepancy modeling in Bayesian calibration and its recent extensions, machine-learning-based discrepancy correction, multi-fidelity and hybrid modeling strategies, as well as residual-based, variational, and adjoint-driven error estimators. Throughout, we emphasize the conceptual underpinnings of implicit versus explicit error treatment and highlight how these methods improve predictive performance and uncertainty quantification in practical applications ranging from engineering design to Earth-system science. Each section provides an overview of key developments with an extensive list of references to facilitate further reading. The review is written for practitioners of large-scale computational physics and engineering simulation, emphasizing how these methods can be incorporated into PDE solvers, inverse problem workflows, and data assimilation systems.
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https://arxiv.org/abs/2511.15934
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b03b69fb4e250a5b2ceb5fa60974a280a37b54522bd20cc3bd1098802bd459c4
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2026-01-23T00:00:00-05:00
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A Comparison between Separately Calibrated P-{\alpha} and Mesoscale Models for Weak Shock Compaction of Granular Sugar
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arXiv:2512.01940v2 Announce Type: replace Abstract: This study compares calibration strategies for predicting particle velocity in granular sugar subjected to weak shock loading, using measurements from flyer-plate impact experiments as a benchmark. Two computational approaches are evaluated: a continuum-based P-alpha Menikoff model requiring calibration of effective constitutive parameters, and mesoscale simulations that explicitly resolve grain geometry and porosity. Both models can match the measured particle-velocity histories, but only through fundamentally different calibration mechanisms. In the P-alpha model, a pressure-dependent yield strength is essential and the response remains highly sensitive to parameter choices such as the crush-out pressure. In contrast, mesoscale simulations are far less sensitive to parameter tuning and instead depend primarily on the physical state variable of porosity, represented in 2D through an equivalent mapping of the 3D specimen. These results show that continuum parameters act as effective surrogates for underlying grain-scale processes, whereas mesoscale modeling identifies porosity as the dominant control on macroscopic wave onset, highlighting distinct calibration pathways and interpretive implications for each modeling approach.
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https://arxiv.org/abs/2512.01940
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9b3e9a80b1876e79f9bed70e7ea3ddbb305fb42c9bec2e6fe119f5e0e52f357c
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2026-01-23T00:00:00-05:00
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The Iris Illusion in the Tropical Sky Seen Through Two Decades of Aura MLS Ice Water Contents
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arXiv:2512.03066v2 Announce Type: replace Abstract: I analyzed ice water content (IWC) data from the Aura Microwave Limb Sounder (MLS) and sea surface temperature (SST) data from NOAA's Optimum Interpolation SST (OISST) product from 2004 to 2024. Using these data, I derived monthly infrared (IR) leakage over the tropics and computed derivatives of both the IR leakage and tropical SST time series from 2005 to 2023. These two derivatives produced a Pearson correlation of -0.49, indicating that IR leakage decreases when SST increases. This behavior contradicts the trend predicted by the Iris hypothesis, suggesting that tropical cirrus clouds strengthen, rather than weaken, as the ocean warms.
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https://arxiv.org/abs/2512.03066
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Academic Papers
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605a3e2c6a7799ead88a8b49132df6988fb4b7a2da1652c3531c492f366f5128
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2026-01-23T00:00:00-05:00
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A low-cost ice melt monitoring system using wind-induced motion of mass-balance stakes
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arXiv:2512.11768v2 Announce Type: replace Abstract: Surface ablation measurements of glaciers are critical for understanding mass change over time. Mass-balance stakes are commonly used for localized measurements, with the exposed length typically measured manually at infrequent intervals. This paper presents the design and validation of new instrumentation that automates mass-balance stake readings, thus enabling continuous measurements with high temporal resolution. The instrumentation comprises readout electronics that are mounted on mass-balance stakes to measure wind-induced vibrations. The stake vibrational frequency depends sensitively on the exposed length, and changes in the measured frequency therefore probe glacier surface melt and accumulation. Initial instrumentation field tests conducted at Color Lake on Umingmat Nunaat (Axel Heiberg Island), Nunavut, demonstrate centimeter-level precision on length measurements. The instrumentation can be attached to existing mass-balance stakes and is low-cost (~ $50 USD) in comparison to many other systems that perform automated surface ablation measurements. The accessibility of this instrumentation opens new possibilities for localized, high temporal resolution measurements of glacier surface activity at any locations where mass balance stakes are deployed.
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https://arxiv.org/abs/2512.11768
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Academic Papers
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6ba0ef7ab54e1dbbad0b95ec3572f6821a2a4a3b1c139e25a9299ee202629f9b
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2026-01-23T00:00:00-05:00
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On flying through the base of a pseudo-streamer
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arXiv:2601.03620v2 Announce Type: replace Abstract: Near the 10 solar radius perihelion of Parker Solar Probe orbit 24, a confined region containing an enhanced plasma density of 25,000 particles per cubic centimeter and broadband electrostatic waves was encountered. The solar wind velocity of 200 kilometers per second and ion temperature of 25 eV were significantly reduced as compared to their values in the ambient solar wind. These anomalous plasma conditions were observed on closed magnetic field lines, as determined from observations of the suprathermal electron strahl. Because the polarity of the radial magnetic field did not change sign on the two sides of the crossing and the crossed region contained a double-peaked plasma structure, the spacecraft must have passed through the base of a pseudo-streamer whose structure extended out to 10 solar radii. In the plasma frame, an electric field as large as 400 millivolts per meter was detected during the crossing. The current associated with this electric field was less than one milliampere per square meter, corresponding to a drift velocity less than 2.5 kilometers per second. It also contained a turbulent plasma with density fluctuations divided by density as large as 0.3, suggesting that the resistive term in the generalized ohm's law was significant. Also, the density as a function of time had a non-zero slope when the electric field was non-zero, suggesting that the pressure gradient term also mattered. As compared to earlier remote sensing and theoretical results, it is surprising that the plasma in this pseudo-streamer had a remarkably low flow velocity and that the pseudo-streamer base extended out to 10 solar radii.
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https://arxiv.org/abs/2601.03620
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6fead47106685cc905f785e10a9b7efd7eea39b49f213c62410cba97979728fe
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2026-01-23T00:00:00-05:00
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On Geometric Evolution and Microlocal Regularity of the Navier-Stokes Equations
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arXiv:2601.08854v2 Announce Type: replace Abstract: We develop a geometric and microlocal framework for the Navier-Stokes equations by lifting the dynamics to the cosphere bundle of a Riemannian manifold. In this formulation, the velocity field and vorticity are represented as microlocal distributions whose evolution is governed by a linear transport-dissipation system generated by a canonical dynamical vector field. We introduce microlocal amplitudes, directional energy functionals, and monotone volume invariants on the compact phase space, which quantify directional concentration and alignment mechanisms associated with potential loss of regularity. The viscous term induces an effective geometric diffusion on the cosphere bundle, yielding closed differential inequalities in a geometric setting. To capture the interaction between fluid deformation and geometry, we define an effective connection and curvature tensor encoding the influence of the symmetric velocity gradient. This structure gives rise to a Ricci-type microlocal geometric evolution that constrains directional stretching and excludes extreme angular concentration compatible with viscous dissipation. While the present results do not resolve the global regularity problem, they provide a coherent geometric mechanism that severely restricts admissible blow--up scenarios, reformulating the regularity question as a problem of dissipative stability on a compact phase space.
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https://arxiv.org/abs/2601.08854
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249548dfed257e5fcf8e3846aab3288ecd64a6ecb7230de6c27d72d6805c8b44
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2026-01-23T00:00:00-05:00
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The Maintenance and Necessity of Universal Rules: Scale, Hierarchy, the Cost of Justice, and Civilizational Development
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arXiv:2601.14325v2 Announce Type: replace Abstract: Building upon previous research, this paper further explores the topological foundations for maintaining universal rules within ultra-large-scale societies. It finds that in small-scale societies, absolute egalitarianism and the rule of law can be compatible through peer monitoring within a fully connected network. However, in ultra-large-scale societies, to maintain high-dimensional rules capable of protecting innovation and property rights, a complex hierarchical structure including "high-fragility" nodes must be constructed. Through quantitative analysis of power structures, this paper proves that a flattened, two-tier structure inevitably leads to the degradation of the rule of law. Only a social topology with sufficient hierarchical depth can escape the deathly trap of the Leviathan while expanding in scale, thereby sustaining the dynamic evolution of civilization.
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https://arxiv.org/abs/2601.14325
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35dbaa303f11067173c874d4ee701a6487f6c0b0a9ab5aa6a9fcf7bd8aeaddeb
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2026-01-23T00:00:00-05:00
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Precision measurement of the ground-state hyperfine constant for $^9Be^+$ in a linear Paul trap via magnetically insensitive hyperfine transitions
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arXiv:2601.14811v2 Announce Type: replace Abstract: Direct measurements of the ground-state magnetically insensitive hyperfine transition |F=2,mF=0>->|F=1,mF=0> of $^9Be^+$ ions have been performed using microwave-driven state transfer. The $^9Be^+$ ions are confined and laser-cooled in a linear Paul trap, forming a Coulomb crystal. The transition frequencies have been measured over a magnetic field range of $ \pm 0.5 mT $ centered at zero magnetic field, and the acquired data were fitted accounting for the high-order Zeeman effect. The hyperfine constant A is determined to be -625.008840(35) MHz, achieving a relative precision of $ 5.6 \times 10^{-8}$.
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https://arxiv.org/abs/2601.14811
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c9f7ddd07166aa2033b0fcf1eef4384826581bd806c14aad20f153d46a289847
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2026-01-23T00:00:00-05:00
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Enhanced posterior sampling via diffusion models for efficient metasurfaces inverse design
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arXiv:2601.15210v2 Announce Type: replace Abstract: The inverse design of metasurfaces faces inherent challenges due to the nonlinear and highly complex relationship between geometric configurations and their electromagnetic behavior. Traditional optimization approaches often suffer from excessive computational demands and a tendency to converge to suboptimal solutions. This study presents a diffusion-based generative framework that incorporates a dedicated consistency constraint and advanced posterior sampling methods to ensure adherence to desired electromagnetic specifications. Through rigorous validation on small-scale metasurface configurations, the proposed approach demonstrates marked enhancements in both accuracy and reliability of the generated designs. Furthermore, we introduce a scalable methodology that extends inverse design capabilities to large-scale metasurfaces, validated for configurations of up to $98 \times 98$ nanopillars. Notably, this approach enables rapid design generation completed in minute by leveraging models trained on substantially smaller arrays ($23 \times 23$). These innovations establish a robust and efficient framework for high-precision metasurface inverse design.
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https://arxiv.org/abs/2601.15210
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30eb918b3367dfecff28dc7ef979ba30be78c0dfea7bf13aadc591e8ea1b7841
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2026-01-23T00:00:00-05:00
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Third-quantized master equations as a classical Ornstein-Uhlenbeck process
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arXiv:2408.11893v3 Announce Type: replace-cross Abstract: Third quantization is used in open quantum systems to construct a superoperator basis in which quadratic Lindbladians can be turned into a normal form. From it follows the spectral properties of the Lindbladian, including eigenvalues and eigenvectors. However, the connection between third quantization and the semiclassical representations usually employed to obtain the dynamics of open quantum systems remains opaque. We introduce an alternative basis for third quantization that bridges this gap between third quantization and the $Q$ representation by projecting the master equation onto a superoperator coherent-state basis. The equation of motion reduces to a multidimensional complex Ornstein-Uhlenbeck process.
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https://arxiv.org/abs/2408.11893
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Academic Papers
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786b18093b0677104d46f6fbee6fb649d4ac54883658786715d0d9b7c23c8755
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2026-01-23T00:00:00-05:00
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Non-hermitian Green's function theory with $N$-body interactions: the coupled-cluster similarity transformation
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arXiv:2503.06586v3 Announce Type: replace-cross Abstract: We present the diagrammatic theory of the irreducible self-energy and Bethe-Salpeter kernel that naturally arises within the Green's function formalism for a general $N$-body non-hermitian interaction. In this work, we focus specifically on the coupled-cluster self-energy generated by the similarity transformation of the electronic structure Hamiltonian. We develop the biorthogonal quantum theory to construct dynamical correlation functions where the time-dependence of operators is governed by a non-hermitian Hamiltonian. We extend the Gell-Mann and Low theorem to include non-hermitian interactions and to generate perturbative expansions of many-body Green's functions. We introduce the single-particle coupled-cluster Green's function and derive the perturbative diagrammatic expansion for the non-hermitian coupled-cluster self-energy in terms of the `non-interacting' reference Green's function, $\tilde{\Sigma}[G_0]$. From the exact equation-of-motion of the single-particle coupled-cluster Green's function, we derive the self-consistent renormalized coupled-cluster self-energy, $\tilde{\Sigma}[\tilde{G}]$, and demonstrate its relationship to the perturbative expansion of the self-energy, $\tilde{\Sigma}[G_0]$. Subsequently, we show that the usual electronic self-energy can be recovered from the coupled-cluster self-energy by neglecting the effects of the similarity transformation. We show how the coupled-cluster ground state energy can be obtained from the coupled-cluster self-energy and provide an overview of the relationship between approximations for the coupled-cluster self-energy, IP/EA-EOM-CC and the $G_0W_0$ approximation. As a result, we introduce the CC-$G_0W_0$ self-energy by leveraging the connections between Green's function and coupled-cluster theory. Finally, we derive the diagrammatic expansion of the coupled-cluster Bethe-Salpeter kernel.
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https://arxiv.org/abs/2503.06586
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67331c5d98e8158727f4f6fb8300f4bf9e8d07c7c90376c1bccd62b6c361ba30
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2026-01-23T00:00:00-05:00
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Turbulent dynamos in a collapsing cloud
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arXiv:2503.19131v2 Announce Type: replace-cross Abstract: The amplification of magnetic fields is crucial for understanding the observed magnetization of stars and galaxies. Turbulent dynamo is the primary mechanism responsible for that but the understanding of its action in a collapsing environment is still rudimentary and relies on limited numerical experiments. We develop an analytical framework and perform numerical simulations to investigate the behavior of small-scale and large-scale dynamos in a collapsing turbulent cloud. This approach is also applicable to expanding environments and facilitates the application of standard dynamo theory to evolving systems. Using a supercomoving formulation of the magnetohydrodynamic (MHD) equations, we demonstrate that dynamo action in a collapsing background leads to a super-exponential growth of magnetic fields in time, significantly faster than the exponential growth seen in stationary turbulence. The enhancement is mainly due to the increasing eddy turnover rate during the collapse, which boosts the instantaneous growth rate of the dynamo. We also show that the scaling of final saturated magnetic field strength with density robustly exceeds the expectation from considerations of pure flux-freezing. Apart from establishing a formal framework for studying magnetic field evolution in collapsing (or expanding) turbulent plasmas, these findings suggest that during star and galaxy formation magnetic fields can become dynamically relevant much earlier than previously thought.
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https://arxiv.org/abs/2503.19131
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86a6bc5b7d7d55577bc0ff59c8c3476e9154abda70d7eec64df375489ecc09e0
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2026-01-23T00:00:00-05:00
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Chaotic Kramers' Law: Hasselmann's Program and AMOC Tipping
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arXiv:2505.18904v2 Announce Type: replace-cross Abstract: In bistable dynamical systems driven by Wiener processes, the widely used Kramers' law relates the strength of the noise forcing to the average time it takes to see a noise-induced transition from one attractor to the other. We extend this law to bistable systems forced by fast chaotic dynamics, which we argue is in some cases a more realistic modeling approach than unbounded noise forcing. Transitions similar to the noise-driven case can only occur if the amplitude of the chaotic forcing is large enough. If this is the case, in our numerical example - a reduced-order model of the Atlantic Meridional Overturning Circulation (AMOC) - we observe the chaotic Kramers' law to hold even when the chaotic forcing is far from the stochastic limit. We discuss the limitations of the chaotic Kramers' law, how to address the numerical issues associated with the timescale separation, and give a possible explanation for the dynamics of recently found AMOC collapses and recoveries in complex climate models.
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https://arxiv.org/abs/2505.18904
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b5e403a3b1254873055666d03994021f9c50b2132c153ff267cff0af48eb7552
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2026-01-23T00:00:00-05:00
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Floquet Non-Bloch Formalism for a Non-Hermitian Ladder: From Theoretical Framework to Topolectrical Circuits
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arXiv:2507.23744v2 Announce Type: replace-cross Abstract: Periodically driven systems intertwined with non-Hermiticity opens a rich arena for topological phases that transcend conventional Hermitian limits. The physical significance of these phases hinges on obtaining the topological invariants that restore the bulk-boundary correspondence, a task well explored for static non-Hermitian (NH) systems, while it remains elusive for the driven scenario. Here, we address this problem by constructing a generalized Floquet non-Bloch framework that analytically captures the spectral and topological properties of time-periodic NH systems. Employing a high-frequency Magnus expansion, we analytically derive an effective Floquet Hamiltonian and formulate the generalized Brillouin zone for a periodically driven quasi-one-dimensional system, namely, the Creutz ladder with a staggered complex potential. Our study demonstrates that the skin effect remains robust (despite the absence of non-reciprocal hopping) across a broad range of driving parameters, and is notably amplified in the low-frequency regime due to emergent longer-range couplings. We further employ a symmetric time frame approach that generates chiral-partner Hamiltonians, whose invariants, when appropriately combined, account for the full edge-state structure. To substantiate the theoretical framework, we propose a topolectrical circuit (TEC) that serves as a viable experimental setting. Apart from capturing the skin modes, the proposed TEC design faithfully reproduces the presence of distinct Floquet edge states, as revealed through the voltage and impedance profiles, respectively. Thus, our work not only offers a theoretical framework for exploring NH-driven systems, but also provides an experimentally feasible TEC architecture for realizing these phenomena stated above in a laboratory.
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https://arxiv.org/abs/2507.23744
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Academic Papers
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