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morphogenesis, the establishment and repair of emergent complex anatomy by groups of cells, is a fascinating and biomedically - relevant problem. one of its most fascinating aspects is that a developing embryo can reliably recover from disturbances, such as splitting into twins. while this reliability implies some type of goal - seeking error minimization over a morphogenic field, there are many gaps with respect to detailed, constructive models of such a process being used to implement the collective intelligence of cellular swarms. we describe a closed - loop negative - feedback system for creating reaction - diffusion ( rd ) patterns with high reliability. it uses a cellular automaton to characterize a morphogen pattern, then compares it to a goal and adjusts accordingly, providing a framework for modeling anatomical homeostasis and robust generation of target morphologies. specifically, we create a rd pattern with n repetitions, where n is easily changeable. furthermore, the individual repetitions of the rd pattern can be easily stretched or shrunk under genetic control to create, e. g., some morphological features larger than others. finally, the cellular automaton uses a computation wave that scans the morphogen pattern unidirectionally to characterize the features that the negative feedback then controls. by taking advantage of a prior process asymmetrically establishing planar polarity ( e. g., head vs. tail ), our automaton is greatly simplified. this work contributes to the exciting effort of understanding design principles of morphological computation, which can be used to understand evolved developmental mechanisms, manipulate them in regenerative medicine settings, or embed a degree of synthetic intelligence into novel bioengineered constructs. | arxiv:2211.01313 |
cecoin5 is a heavy fermion type - ii superconductor which exhibits clear indications of pauli - limited superconductivity. a variety of measurements give evidence for a transition at high magnetic fields inside the superconducting state, when the field is applied either parallel to or perpendicular to the c axis. when the field is perpendicular to the c axis, antiferromagnetic order is observed on the high - field side of the transition, with a magnetic wavevector of ( q q 0. 5 ), where q = 0. 44 reciprocal lattice units. we show that this order remains as the magnetic field is rotated out of the basal plane, but the associated moment eventually disappears above 17 degrees, indicating that the anomalies seen with the field parallel to the c axis are not related to this magnetic order. we discuss the implications of this finding. | arxiv:1009.2883 |
we present numerical evidence that in a system of interacting bosons there exists a correspondence between the spectral properties of the exact quantum hamiltonian and the dynamical chaos of the associated mean field evolution. this correspondence, analogous to the usual quantum - classical correspondence, is related to the formal parallel between the second quantization of the mean field, which generates the exact dynamics of the quantum $ n $ - body system, and the first quantization of classical canonical coordinates. the limit of infinite density and the thermodynamic limit are then briefly discussed. | arxiv:cond-mat/9604084 |
an important line of research in the field of explainability is to extract a small subset of crucial rationales from the full input. the most widely used criterion for rationale extraction is the maximum mutual information ( mmi ) criterion. however, in certain datasets, there are spurious features non - causally correlated with the label and also get high mutual information, complicating the loss landscape of mmi. although some penalty - based methods have been developed to penalize the spurious features ( e. g., invariance penalty, intervention penalty, etc ) to help mmi work better, these are merely remedial measures. in the optimization objectives of these methods, spurious features are still distinguished from plain noise, which hinders the discovery of causal rationales. this paper aims to develop a new criterion that treats spurious features as plain noise, allowing the model to work on datasets rich in spurious features as if it were working on clean datasets, thereby making rationale extraction easier. we theoretically observe that removing either plain noise or spurious features from the input does not alter the conditional distribution of the remaining components relative to the task label. however, significant changes in the conditional distribution occur only when causal features are eliminated. based on this discovery, the paper proposes a criterion for \ textbf { m } aximizing the \ textbf { r } emaining \ textbf { d } iscrepancy ( mrd ). experiments on six widely used datasets show that our mrd criterion improves rationale quality ( measured by the overlap with human - annotated rationales ) by up to $ 10. 4 \ % $ as compared to several recent competitive mmi variants. code : \ url { https : / / github. com / jugechengzi / rationalization - mrd }. | arxiv:2410.06003 |
osmnx is a python package for downloading, modeling, analyzing, and visualizing urban networks and any other geospatial features from openstreetmap data. a large and growing body of literature uses it to conduct scientific studies across the disciplines of geography, urban planning, transport engineering, computer science, and others. the osmnx project has recently developed and implemented many new features, modeling capabilities, and analytical methods. the package now encompasses substantially more functionality than was previously documented in the literature. this article introduces osmnx ' s modern capabilities, usage, and design - - in addition to the scientific theory and logic underlying them. it shares lessons learned in geospatial software development and reflects on open science ' s implications for urban modeling and analysis. | arxiv:2505.00736 |
computer systems are full of heuristic rules which drive the decisions they make. these rules of thumb are designed to work well on average, but ignore specific information about the available context, and are thus sub - optimal. the emerging field of machine learning for systems attempts to learn decision rules with machine learning algorithms. in the database community, many recent proposals have been made to improve selectivity estimation with batch machine learning methods. such methods are all batch methods which require retraining and cannot handle concept drift, such as workload changes and schema modifications. we present online machine learning as an alternative approach. online models learn on the fly and do not require storing data, they are more lightweight than batch models, and finally may adapt to concept drift. as an experiment, we teach models to improve the selectivity estimates made by postgresql ' s cost model. our experiments make the case that simple online models are able to compete with a recently proposed deep learning method. | arxiv:2009.09884 |
the paper continues the rigorous investigations of the mean field green function solution of the effective two - dimensional two - band hubbard model [ n. m. plakida et al., phys. rev. b, vol. 51, 16599 ( 1995 ) ] of the superconducting phase transitions in cuprates, started in [ gh. adam, s. adam, j. phys. a : math. theor., vol. 40, 11205 ( 2007 ) ]. discussion of the $ ( \ delta, t ) $ phase diagram of the model points to the divergence of the energy spectrum in the limit of vanishing doping $ \ delta $. finite energy spectra at all possible doping rates $ \ delta $ are obtained provided the hopping part of the effective hamiltonian is renormalized with an effective factor pointing to the site - pairs availability for fermion hopping processes. | arxiv:0903.1563 |
given a complex manifold $ m $ with an open dense subset $ \ omega $ endowed with a pseudo - kaehler form $ \ omega $ which cannot be smoothly extended to a larger open subset, we consider various examples where the corresponding kaehler - poisson structure and a star product with separation of variables on $ ( \ omega, \ omega ) $ admit smooth extensions to $ m $. we suggest a simple criterion of the existence of a smooth extension of a star product and apply it to these examples. | arxiv:1012.5495 |
it is well known that a particle in a periodic potential with an additional constant force performs bloch oscillations. modulating every second period of the potential, the original bloch band splits into two subbands. the dynamics of quantum particles shows a coherent superposition of bloch oscillations and zener tunneling between the subbands, a bloch - zener oscillation. such a system is modelled by a tight - binding hamiltonian, a system of two minibands with an easily controllable gap. the dynamics of the system is investigated by using an algebraic ansatz leading to a differential equation of whittaker - hill type. it is shown that the parameters of the system can be tuned to generate a periodic reconstruction of the wave packet and thus of the occupation probability. as an application, the construction of a matter wave beam splitter and a mach - zehnder interferometer is briefly discussed. | arxiv:quant-ph/0603093 |
the current analysis of atmospheric neutrinos by the super - kamiokande collaboration is based only on fully - contained one - ring events and partially contained events. we show that the up - down ratio of fully - contained, inclusive, multi - ring events gives an independent test of the atmospheric neutrino anomaly, without the need for particle identification. moreover, this class of events is rich in neutral current events and hence gives crucial information for discriminating between oscillations of \ nu _ \ mu into \ nu _ { e, \ tau } and \ nu _ s. | arxiv:hep-ph/9806218 |
using a code based on the lattice boltzmann equation, we have performed numerical simulations of a turbulent shear flow. we investigate the scaling behaviour of the structure functions in presence of anisotropic homogeneous turbulence, and we show that although extended self similarity does not hold when strong shear effects are present, a more generalized scaling law can still be defined. | arxiv:chao-dyn/9509018 |
windows in euclidean time have become a standard tool for comparing lattice qcd and data - driven computations of the hadronic vacuum polarization ( hvp ) contribution to the muon $ g - 2 $. here we review our results, obtained using isospin - rotated $ \ tau ^ - \ to \ pi ^ - \ pi ^ 0 \ nu _ \ tau $ data instead of $ e ^ + e ^ - \ to \ pi ^ + \ pi ^ - $ measurements, and compare them to other approaches. consistency of the tau - based and lattice results hints to underestimated uncertainties in the $ e ^ + e ^ - $ data. if that is the case, the theory prediction of the muon $ g - 2 $ would only lie at $ \ sim 2 \ sigma $ from its measured value. | arxiv:2310.14102 |
we propose an arithmetic mckay correspondence which relates suitably defined zeta functions of some deligne - mumford stacks to the zeta functions of their crepant resolutions. some examples are discussed. | arxiv:0812.4202 |
we consider an exact foldy - wouthuysen transformation for the dirac spinor field on the combined background of a gravitational wave and constant uniform magnetic field. by taking the classical limit of the spinor field hamiltonian we arrive at the equations of motion for the non - relativistic spinning particle. two different kinds of the gravitational fields are considered and in both cases the effect of the gravitational wave on the spinor field and on the corresponding spinning particle may be enforced by the sufficiently strong magnetic field. this result can be relevant for the astrophysical applications and, in principle, useful for creating the gravitational wave detectors based on atomic physics and precise interferometry. | arxiv:0709.0767 |
a generalized fermi - bose mapping method is used to determine the exact ground states of several models of mixtures of strongly interacting ultracold gases in tight waveguides, which are generalizations of the tonks - girardeau ( tg ) gas ( 1d bose gas with point hard cores ) and fermionic tonks - girardeau ( ftg ) gas ( 1d spin - aligned fermi gas with infinitely strong zero - range attractions ). we detail the case of a bose - fermi mixture with tg boson - boson ( bb ) and boson - fermion ( bf ) interactions. exact results are given for density profiles in a harmonic trap, single - particle density matrices, momentum distributions, and density - density correlations. since the ground state is highly degenerate, we analyze the splitting of the ground manifold for large but finite bb and bf repulsions. | arxiv:0706.1797 |
a fundamental result of toric geometry is that there is a bijection between toric varieties and fans. more generally, it is known that some class of manifolds having well - behaved torus actions, called topological toric manifolds $ m ^ { 2n } $, can be classified in terms of combinatorial data containing simplicial complexes with $ m $ vertices. we remark that topological toric manifolds are a generalization of smooth toric varieties. the number $ m - n $ is known as the picard number when $ m ^ { 2n } $ is a { compact smooth } toric variety. in this paper, we investigate the relationship between the topological toric manifolds over a simplicial complex $ k $ and those over the complex obtained by simplicial wedge operations from $ k $. as applications, we do the following. 1. we classify smooth toric varieties of picard number 3. this is a reproving of a result of batyrev. 2. we give a new and complete proof of projectivity of smooth toric varieties of picard number 3 originally proved by kleinschmidt and sturmfels. 3. we find a criterion for a toric variety over the join of boundaries of simplices to be projective. when the toric variety is smooth, it is known as a generalized bott manifold which is always projective. 4. we classify and enumerate real topological toric manifolds when $ m - n = 3 $. 5. when $ m - n \ leq 3 $, any real topological toric manifold is realizable as fixed points of the conjugation of a topological toric manifold. | arxiv:1305.0136 |
spectral clustering is discussed from many perspectives, by extending it to rectangular arrays and discrepancy minimization too. near optimal clusters are obtained with singular value decomposition and with the weighted $ k $ - means algorithm. in case of rectangular arrays, this means enhancing the method of correspondence analysis with clustering, and in case of edge - weighted graphs, a normalized laplacian based clustering. in the latter case it is proved that a spectral gap between the $ ( k - 1 ) $ th and $ k $ th smallest positive eigenvalues of the normalized laplacian matrix gives rise to a sudden decrease of the inner cluster variances when the number of clusters of the vertex representatives is $ 2 ^ { k - 1 } $, but only the first $ k - 1 $ eigenvectors, constituting the so - called fiedler - carpet, are used in the representation. application to directed migration graphs is also discussed. | arxiv:2112.10637 |
we present a map of the cosmic microwave background ( cmb ) anisotropies induced by the late integrated sachs wolfe effect. the map is constructed by combining the information of the wmap 7 - yr cmb data and the nrao vla sky survey ( nvss ) through a linear filter. this combination improves the quality of the map that would be obtained using information only from the large scale structure data. in order to apply the filter, a given cosmological model needs to be assumed. in particular, we consider the standard lcdm model. as a test of consistency, we show that the reconstructed map is in agreemet with the assumed model, which is also favoured against a scenario where no correlation between the cmb and nvss catalogue is considered. | arxiv:1208.2350 |
we present a universal knot polynomials for 2 - and 3 - strand torus knots in adjoint representation, by universalization of appropriate rosso - jones formula. according to universality, these polynomials coincide with adjoined colored homfly and kauffman polynomials at sl and so / sp lines on vogel ' s plane, and give their exceptional group ' s counterparts on exceptional line. we demonstrate that [ m, n ] = [ n, m ] topological invariance, when applicable, take place on the entire vogel ' s plane. we also suggest the universal form of invariant of figure eight knot in adjoint representation, and suggest existence of such universalization for any knot in adjoint and its descendant representation. properties of universal polynomials and applications of these results are discussed. | arxiv:1510.05884 |
deep neural networks ( dnns ) have recently achieved great success in many classification tasks. unfortunately, they are vulnerable to adversarial attacks that generate adversarial examples with a small perturbation to fool dnn models, especially in model sharing scenarios. adversarial training is proved to be the most effective strategy that injects adversarial examples into model training to improve the robustness of dnn models against adversarial attacks. however, adversarial training based on the existing adversarial examples fails to generalize well to standard, unperturbed test data. to achieve a better trade - off between standard accuracy and adversarial robustness, we propose a novel adversarial training framework called latent boundary - guided adversarial training ( ladder ) that adversarially trains dnn models on latent boundary - guided adversarial examples. as opposed to most of the existing methods that generate adversarial examples in the input space, ladder generates a myriad of high - quality adversarial examples through adding perturbations to latent features. the perturbations are made along the normal of the decision boundary constructed by an svm with an attention mechanism. we analyze the merits of our generated boundary - guided adversarial examples from a boundary field perspective and visualization view. extensive experiments and detailed analysis on mnist, svhn, celeba, and cifar - 10 validate the effectiveness of ladder in achieving a better trade - off between standard accuracy and adversarial robustness as compared with vanilla dnns and competitive baselines. | arxiv:2206.03717 |
we consider symmetry protected topological ( spt ) phases with finite non - invertible symmetry $ \ mathcal { c } $ in 1 + 1d. in particular, we investigate interfaces and parameterized families of them within the framework of matrix product states. after revealing how to extract the $ \ mathcal { c } $ - spt invariant, we identify the algebraic structure of symmetry operators acting on the interface of two $ \ mathcal { c } $ - spt phases. by studying the representation theory of this algebra, we show that there must be a degenerate interface mode between different $ \ mathcal { c } $ - spt phases. this result generalizes the bulk - boundary correspondence for ordinary spt phases. we then propose the classification of one - parameter families of $ \ mathcal { c } $ - spt states based on the explicit construction of invariants of such families. our invariant is identified with a non - abelian generalization of the thouless charge pump, which is the pump of a local excitation within a $ \ mathcal { c } $ - spt phase. finally, by generalizing the results for one - parameter families of spt phases, we conjecture the classification of general parameterized families of general gapped phases with finite non - invertible symmetries in both 1 + 1d and higher dimensions. | arxiv:2408.15960 |
the fundamental gates of linear optics quantum computation are realized by using single photons sources, linear optics and photon counters. success of these gates is conditioned on the pattern of photons detected without using feedback. here it is shown that the maximum probability of success of these gates is typically strictly less than 1. for the one - mode non - linear sign shift, the probability of success is bounded by 1 / 2. for the conditional sign shift of two modes, this probability is bounded by 3 / 4. these bounds are still substantially larger than the highest probabilities shown to be achievable so far, which are 1 / 4 and 2 / 27, respectively. | arxiv:quant-ph/0307015 |
making predictions that are fair with regard to protected group membership ( race, gender, age, etc. ) has become an important requirement for classification algorithms. existing techniques derive a fair model from sampled labeled data relying on the assumption that training and testing data are identically and independently drawn ( iid ) from the same distribution. in practice, distribution shift can and does occur between training and testing datasets as the characteristics of individuals interacting with the machine learning system change. we investigate fairness under covariate shift, a relaxation of the iid assumption in which the inputs or covariates change while the conditional label distribution remains the same. we seek fair decisions under these assumptions on target data with unknown labels. we propose an approach that obtains the predictor that is robust to the worst - case in terms of target performance while satisfying target fairness requirements and matching statistical properties of the source data. we demonstrate the benefits of our approach on benchmark prediction tasks. | arxiv:2010.05166 |
diffusion - based visuomotor policies excel at learning complex robotic tasks by effectively combining visual data with high - dimensional, multi - modal action distributions. however, diffusion models often suffer from slow inference due to costly denoising processes or require complex sequential training arising from recent distilling approaches. this paper introduces riemannian flow matching policy ( rfmp ), a model that inherits the easy training and fast inference capabilities of flow matching ( fm ). moreover, rfmp inherently incorporates geometric constraints commonly found in realistic robotic applications, as the robot state resides on a riemannian manifold. to enhance the robustness of rfmp, we propose stable rfmp ( srfmp ), which leverages lasalle ' s invariance principle to equip the dynamics of fm with stability to the support of a target riemannian distribution. rigorous evaluation on eight simulated and real - world tasks show that rfmp successfully learns and synthesizes complex sensorimotor policies on euclidean and riemannian spaces with efficient training and inference phases, outperforming diffusion policies while remaining competitive with consistency policies. | arxiv:2412.10855 |
given a smooth toric variety x and an ample line bundle o ( 1 ), we construct a sequence of lagrangian submanifolds of ( c ^ * ) ^ n with boundary on a level set of the landau - ginzburg mirror of x. the corresponding floer homology groups form a graded algebra under the cup product which is canonically isomorphic to the homogeneous coordinate ring of x. | arxiv:math/0511644 |
surface acoustic wave ( saw ) devices form an important class of acoustofluidic devices, in which the acoustic waves are generated and propagate along the surface of a piezoelectric substrate. despite their wide - spread use, only a few fully three - dimensional ( 3d ) numerical simulations have been presented in the literature. in this paper, we present a 3d numerical simulation taking into account the electromechanical fields of the piezoelectric saw device, the acoustic displacement field in the attached elastic material, in which the liquid - filled microchannel is embedded, the acoustic fields inside the microchannel, as well as the resulting acoustic radiation force and streaming - induced drag force acting on micro - and nanoparticles suspended in the microchannel. a specific device design is presented, for which the numerical predictions of the acoustic resonances and the acoustophoretic repsonse of suspended microparticles in 3d are successfully compared with experimental observations. the simulation provides a physical explanation of the the observed qualitative difference between devices with an acoustically soft and hard lid in terms of traveling and standing waves, respectively. the simulations also correctly predict the existence and position of the observed in - plane streaming flow rolls. the presented simulation model may be useful in the development of saw devices optimized for various acoustofluidic tasks. | arxiv:1907.13233 |
three planets with minimum masses less than 10 earth masses orbit the star hd 40307, suggesting these planets may be rocky. however, with only radial velocity data, it is impossible to determine if these planets are rocky or gaseous. here we exploit various dynamical features of the system in order to assess the physical properties of the planets. observations allow for circular orbits, but a numerical integration shows that the eccentricities must be at least 0. 0001. also, planets b and c are so close to the star that tidal effects are significant. if planet b has tidal parameters similar to the terrestrial planets in the solar system and a remnant eccentricity larger than 0. 001, then, going back in time, the system would have been unstable within the lifetime of the star ( which we estimate to be 6. 1 + / - 1. 6 gyr ). moreover, if the eccentricities are that large and the inner planet is rocky, then its tidal heating may be an order of magnitude greater than extremely volcanic io, on a per unit surface area basis. if planet b is not terrestrial, e. g. neptune - like, these physical constraints would not apply. this analysis suggests the planets are not terrestrial - like, and are more like our giant planets. in either case, we find that the planets probably formed at larger radii and migrated early - on ( via disk interactions ) into their current orbits. this study demonstrates how the orbital and dynamical properties of exoplanet systems may be used to constrain the planets ' physical properties. | arxiv:0901.1698 |
in this paper, we establish the expected order of magnitude of the $ k $ th - moment of central values of the family of dirichlet $ l $ - functions to a fixed prime modulus over function fields for all real $ k \ geq 0 $. | arxiv:2203.14458 |
the charge dynamics in weakly hole doped high temperature superconductors is studied in terms of the accurate numerical solution to a model of a single hole interacting with a quantum lattice in an antiferromagnetic background, and accurate far - infrared ellipsometry measurements. the experimentally observed two electronic bands in the infrared spectrum can be identified in terms of the interplay between the electron correlation and electron - phonon interaction resolving the long standing mystery of the mid - infrared band. | arxiv:0804.0479 |
we investigate convergence of point processes associated with critical faces for a \ v { c } ech filtration built over a homogeneous poisson point process in the $ d $ - dimensional flat torus. the convergence of our point process is established in terms of the $ \ mathcal m _ 0 $ - topology, when the connecting radius of a \ v { c } ech complex decays to $ 0 $, so slowly that critical faces are even less likely to occur than those in the regime of threshold for homological connectivity. we also obtain a series of limit theorems for positive and negative critical faces, all of which are considerably analogous to those for critical faces. | arxiv:2309.06431 |
conventional text - to - speech ( tts ) research has predominantly focused on enhancing the quality of synthesized speech for speakers in the training dataset. the challenge of synthesizing lifelike speech for unseen, out - of - dataset speakers, especially those with limited reference data, remains a significant and unresolved problem. while zero - shot or few - shot speaker - adaptive tts approaches have been explored, they have many limitations. zero - shot approaches tend to suffer from insufficient generalization performance to reproduce the voice of speakers with heavy accents. while few - shot methods can reproduce highly varying accents, they bring a significant storage burden and the risk of overfitting and catastrophic forgetting. in addition, prior approaches only provide either zero - shot or few - shot adaptation, constraining their utility across varied real - world scenarios with different demands. besides, most current evaluations of speaker - adaptive tts are conducted only on datasets of native speakers, inadvertently neglecting a vast portion of non - native speakers with diverse accents. our proposed framework unifies both zero - shot and few - shot speaker adaptation strategies, which we term as " instant " and " fine - grained " adaptations based on their merits. to alleviate the insufficient generalization performance observed in zero - shot speaker adaptation, we designed two innovative discriminators and introduced a memory mechanism for the speech decoder. to prevent catastrophic forgetting and reduce storage implications for few - shot speaker adaptation, we designed two adapters and a unique adaptation procedure. | arxiv:2404.18094 |
" inspires a desire to press the buttons ". musicians who have used the op - 1 include bon iver, beck, depeche mode, jean michel jarre, caroline rose, and ivan dorn. = = products = = op - 1 synthesizer / sampler / sequencer ( introduced january 2010 ) px - 0 earbuds ( introduced 2011, collaboration with aiaiai, discontinued ) oplab ( introduced january 2012 ) od - 11 wireless loudspeaker ( introduced january 2013 ) ortho remote remote controller ( introduced january 2013 ) po - 12 rhythm drum machine / sequencer, po - 14 sub synthesizer / sequencer & po - 16 factory synthesizer / sequencer ( introduced january 2015 ; collaboration with cheap monday ) impossible i - 1 ( introduced may 2016 ; designed by teenage engineering for the impossible project ) po - 20 arcade synthesizer / sequencer, po - 24 office drum machine / sequencer & po - 28 robot synthesizer / sequencer ( introduced january 2016 ; collaboration with cheap monday ) po - 32 tonic synthesizer and sequencer ( introduced january 2017 ) h ( introduced november 2017 ; designed by teenage engineering for raven ) r ( introduced november 2017 ; designed by teenage engineering for raven ) po - 33 ko! & po - 35 speak ( introduced january 2018 ) frekvens collection ( introduced april 2018 ; designed by teenage engineering for ikea ) op - z synthesizer and sequencer ( introduced september 2018 ) pocket operator modular series ( pom - 16 keyboard / sequencer, pom - 170 analog synthesizer / sequencer & pom - 400 analog synthesizer ) ( introduced january 2019 ) po - 137 rick and morty ( introduced july 2019 ; collaboration with adult swim ( rick and morty ) ) playdate game console ( introduced may 2019 ; designed by teenage engineering for panic inc. ) m - 1 headphones ( introduced december 2019 ) ob - 4 radio ( introduced september 2020 ) po - 128 mega man & po - 133 streetfighter ( introduced october 2020 ; collaboration with capcom ) ear ( 1 ) ( introduced july 2021 ; designed by teenage engineering for nothing ) mayku multiplier ( introduced september 2021 ; designed by teenage engineering for mayku ) computer - 1 computer case ( introduced october 2021 ) tx - 6 field mixer ( introduced april 2022 ) op - 1 field synthesizer ( introduced may 2022 ) po - 80 portable record player and engraver ( introduced october 2022 ; collaboration with yuri suzuki ) ch - 8 singing wooden dolls ( introduced november 2022 ) cm - 15 microphone ( introduced april 202 | https://en.wikipedia.org/wiki/Teenage_Engineering |
anisotropic lattices, with a temporal lattice spacing smaller than the spatial one, allow precision monte carlo calculations of problems that are difficult to study otherwise : heavy quarks, glueballs, hybrids, and high temperature thermodynamics, for example. we here perform the first step required for such studies with the ( quenched ) wilson gauge action, namely, the determination of the renormalized anisotropy $ \ xi $ as a function of the bare anisotropy $ \ xi _ 0 $ and the coupling. by, essentially, comparing the finite - volume heavy quark potential where the quarks are separated along a spatial direction with that where they are separated along the time direction, we determine the relation between $ \ xi $ and $ \ xi _ 0 $ to a fraction of 1 % for weak and to 1 % for strong coupling. we present a simple parameterization of this relation for $ 1 \ leq \ xi \ leq 6 $ and $ 5. 5 \ leq \ beta \ leq \ infty $, which incorporates the known one - loop result and reproduces our non - perturbative determinations within errors. besides solving the problem of how to choose the bare anisotropies if one wants to take the continuum limit at fixed renormalized anisotropy, this parameterization also yields accurate estimates of the derivative $ \ partial \ xi _ 0 / \ partial \ xi $ needed in thermodynamic studies. | arxiv:hep-lat/9803010 |
we theoretically demonstrate the coupling between excitons in 2d semiconductors and surface plasmons in a thin metal film by means of a surface acoustic wave ( saw ), proving that the generated exciton - plasmon polaritons ( or plexcitons ) are in the strong coupling regime. the strain field of the saw creates a dynamic diffraction grating providing the momentum match for the surface plasmons, whereas the piezoelectric field, that could dissociate the excitons, is cancelled out by the metal. this is exemplified for monolayer mos $ \ mathrm { _ { 2 } } $ and mono - and few - layer black phosphorus on top of a thin silver layer on a linbo $ \ mathrm { _ { 3 } } $ piezoelectric substrate, providing rabi splittings of 100 - 150 mev. thus, we demonstrate that saws are powerful tools to modulate the optical properties of supported 2d semiconductors by means of the high - frequency localized deformations tailored by the acoustic transducers, that can serve as electrically switchable launchers of propagating plexcitons suitable for active high - speed nanophotonic applications. | arxiv:2012.11695 |
probably not, but it is interesting nevertheless to investigate just how close cas a might have come to generating such an event. focusing on the northeast jet filaments, we analyze the polar regions of the recently acquired very deep 1 ms chandra x - ray observation. we infer that the so - called " jet " regions are indeed due to jets emanating from the explosion center, and not due to polar cavities in the circumstellar medium at the time of explosion. we place limits on the equivalent isotropic explosion energy in the polar regions ( around 2. 3 x 10 ^ 52 ergs ), and the opening angle of the x - ray emitting ejecta ( around 7 degrees ), which give a total energy in the ne jet of order 10 ^ 50 ergs ; an order of magnitude or more lower than inferred for " typical " grbs. while the cas a progenitor and explosion exhibit many of the features associated with grb hosts, e. g. extensive presupernova mass loss and rotation, and jets associated with the explosion, we speculate that the recoil of the compact central object, with velocity 330 km / s, may have rendered the jet unstable. in such cases the jet rapidly becomes baryon loaded, if not truncated altogether. although unlikely to have produced a gamma ray burst, the jets in cas a suggest that such outflows may be common features of core - collapse sne. | arxiv:astro-ph/0603434 |
we consider the solution to a stochastic differential equation with a drift function which depends smoothly on some real parameter $ \ lambda $, and admitting a unique invariant measure for any value of $ \ lambda $ around $ \ lambda $ = 0. our aim is to compute the derivative with respect to $ \ lambda $ of averages with respect to the invariant measure, at $ \ lambda $ = 0. we analyze a numerical method which consists in simulating the process at $ \ lambda $ = 0 together with its derivative with respect to $ \ lambda $ on long time horizon. we give sufficient conditions implying uniform - in - time square integrability of this derivative. this allows in particular to compute efficiently the derivative with respect to $ \ lambda $ of the mean of an observable through monte carlo simulations. | arxiv:1509.01348 |
magnetic properties of the intermetallic compound ndco $ _ 2 $ si $ _ 2 $ are investigated by using the monte carlo simulation ( mcs ) under metropolis algorithm. the magnetism of the compound is caused by the existence of the rare earth ( nd3 + ) ions with a magnetic moment taking the value 2. 7 mub. firstly, the ground state phase diagrams are presented and discussed in different planes corresponding to different physical parameters of the system. the stable phases are explored for different configurations of the hamiltonian of the system. these stable phases are determined by the minimal energies. for non - null temperature values, we compute the magnetizations and susceptibilities behaviors as a function of temperature by using the monte carlo simulations ( mcs ). also, we present the magnetization behaviors as a function of the exchange coupling interactions, the crystal field and the external magnetic field. finally, we present and discuss the magnetic hysteresis loops of the intermetallic ndco2si2 compound as a function of the external magnetic field for fixed values of temperature and the other physical parameters. | arxiv:1912.04245 |
we develop a new theory for associating fluids with multiple association sites. the theory accounts for small bond angle effects such as steric hindrance, ring formation and double bonding. the theory is validated against monte carlo simulations for the case of a fluid of patchy colloid particles with three patches and is found to be very accurate. once validated, the theory is applied to study the phase diagram of a fluid composed of three patch colloids. it is found that bond angle has a significant effect on the phase diagram and the very existence of a liquid - vapor transition. | arxiv:1308.3534 |
if v ( r ) is the vertex sequence of a symmetric cycle r in the tope graph of a simple acyclic oriented matroid m on a t - element ground set, then the set min v ( r ) of minimal elements in the subposet v ( r ) of the tope poset of m, based at the positive tope, is a critical committee for m that votes for the base tope. we consider the sequence zr of poset ranks of the elements from the vertex sequence of r as a fragment of a signal with period 2t and relate the number of members of the committee min v ( r ) to the magnitudes of [ t / 2 ] components, with odd indices, of the discrete fourier transform of the distance vector zr. | arxiv:1303.5350 |
given a sequence of regular finite coverings of complete riemannian manifolds, we consider the covering solenoid associated with the sequence. we study the leaf - wise laplacian on the covering solenoid. the main result is that the spectrum of the laplacian on the covering solenoid equals the closure of the union of the spectra of the manifolds in the sequence. we offer an equivalent statement of selberg ' s 1 / 4 conjecture. | arxiv:1907.06712 |
we present a multi - probe analysis of the well - known galaxy cluster cl j1226. 9 + 3332 as a proof of concept for multi - wavelength studies within the framework of the nika2 sunyaev - zeldovich large program ( lpsz ). cl j1226. 9 + 3332 is a massive and high redshift ( z = 0. 888 ) cluster that has already been observed at several wavelengths. a joint analysis of the thermal sz ( tsz ) effect at millimeter wavelength with the nika2 camera and in x - ray with the xmm - newton satellite permits the reconstruction of the cluster thermodynamical properties and mass assuming hydrostatic equilibrium. we test the robustness of our mass estimates against different definitions of the data analysis transfer function. using convergence maps reconstructed from the data of the clash program we obtain estimates of the lensing mass, which we compare to the estimated hydrostatic mass. this allows us to measure the hydrostatic - to - lensing mass bias and the associated systematic effects related to the nika2 measurement. we obtain m500hse = ( 7. 65 + - 1. 03 ) 1014 msun and m500lens = ( 7. 35 + - 0. 65 ) 1014 msun, which implies a hse - to - lensing bias consistent with 0 within 20 percent. | arxiv:2111.01685 |
high dose rate brachytherapy ( hdr - bt ) is an appealing treatment option for superficial cancers that permits the delivery of higher local doses than other radiation modalities without a significant increase in toxicity. in order for hdr - bt to be used in these situations, needles through which the radiation source is passed must be strategically placed in close proximity to the patient ' s body. currently, this crucial step is performed manually by physicians or medical physicists. the use of 3d - printed masks customized for individual patients has been advocated as a way to more precisely and securely position these needles, with the potential of producing better and safer treatment plans. in this paper, we propose optimization approaches for positioning needles within 3d - printed masks for hdr - bt, focusing on skin cancers. we numerically show that the models we propose efficiently generate more homogeneous plans than those derived manually and provide an alternative to manual placement that can save planning time and enhance plan quality. | arxiv:2503.06000 |
we present a model of public good provision with a distributor. our main result describes a symmetric mixed - strategy equilibrium, where all agents contribute to a common fund with probability $ p $ and the distributor provides either a particular amount of public goods or nothing. a corollary of this finding is the efficient public good provision equilibrium where all agents contribute to the common fund, all agents are expected to contribute, and the distributor spends the entire common fund for the public good provision. | arxiv:2210.10642 |
we consider a singular limit problem from the damped wave equation with a power type nonlinearity to the corresponding heat equation. we call our singular limit problem non - delay limit. our proofs are based on the argument for non - relativistic limit from the nonlinear klein - gordon equation to the nonlinear schr \ " { o } dinger equation by the second author, nakanishi, and ozawa ( 2002 ), nakanishi ( 2002 ), and masmoudi and nakanishi ( 2002 ). we can obtain better results for the non - delay limit problem than that for the non - relativistic limit problem due to the dissipation property. more precisely, we get the better convergence rate of the $ l ^ 2 $ - norm and we also obtain the global - in - time uniform convergence of the non - delay limit in the $ l ^ 2 $ - supercritical case. | arxiv:2106.03030 |
with the rapid development and application of foundation models ( fms ), it is foreseeable that fms will play an important role in future wireless communications. as current artificial intelligence ( ai ) algorithms applied in wireless networks are dedicated models that aim for different neural network architectures and objectives, drawbacks in aspects of generality, performance gain, management, collaboration, etc. need to be conquered. in this paper, we define netgpt ( network generative pre - trained transformer ) - - the foundation models for wireless communications, and summarize ten issues regarding design and application of netgpt. | arxiv:2311.13106 |
##dii ) of angle θ, with θ measured in radians, is given by a = θ 2 ( r 2 − r 2 ). { \ displaystyle a = { \ frac { \ theta } { 2 } } \ left ( r ^ { 2 } - r ^ { 2 } \ right ). } = = complex structure = = in complex analysis an annulus ann ( a ; r, r ) in the complex plane is an open region defined as r < | z − a | < r. { \ displaystyle r < | z - a | < r. } if r = 0 { \ displaystyle r = 0 }, the region is known as the punctured disk ( a disk with a point hole in the center ) of radius r around the point a. as a subset of the complex plane, an annulus can be considered as a riemann surface. the complex structure of an annulus depends only on the ratio r / r. each annulus ann ( a ; r, r ) can be holomorphically mapped to a standard one centered at the origin and with outer radius 1 by the map z ↦ z − a r. { \ displaystyle z \ mapsto { \ frac { z - a } { r } }. } the inner radius is then r / r < 1. the hadamard three - circle theorem is a statement about the maximum value a holomorphic function may take inside an annulus. the joukowsky transform conformally maps an annulus onto an ellipse with a slit cut between foci. = = see also = = annular cutter – form of core drill annulus theorem / conjecture – in mathematics, on the region between two well - behaved spheres focaloid – geometric shell bounded by two concentric, similar ellipses or ellipsoidspages displaying short descriptions of redirect targets list of geometric shapes – list of listspages displaying short descriptions of redirect targets spherical shell – three - dimensional geometric shape torus – doughnut - shaped surface of revolution = = references = = = = external links = = annulus definition and properties with interactive animation area of an annulus, formula with interactive animation | https://en.wikipedia.org/wiki/Annulus_(mathematics) |
alternating minimization is a widely used and empirically successful heuristic for matrix completion and related low - rank optimization problems. theoretical guarantees for alternating minimization have been hard to come by and are still poorly understood. this is in part because the heuristic is iterative and non - convex in nature. we give a new algorithm based on alternating minimization that provably recovers an unknown low - rank matrix from a random subsample of its entries under a standard incoherence assumption. our results reduce the sample size requirements of the alternating minimization approach by at least a quartic factor in the rank and the condition number of the unknown matrix. these improvements apply even if the matrix is only close to low - rank in the frobenius norm. our algorithm runs in nearly linear time in the dimension of the matrix and, in a broad range of parameters, gives the strongest sample bounds among all subquadratic time algorithms that we are aware of. underlying our work is a new robust convergence analysis of the well - known power method for computing the dominant singular vectors of a matrix. this viewpoint leads to a conceptually simple understanding of alternating minimization. in addition, we contribute a new technique for controlling the coherence of intermediate solutions arising in iterative algorithms based on a smoothed analysis of the qr factorization. these techniques may be of interest beyond their application here. | arxiv:1312.0925 |
we introduce a family of three parameters 2 - dimensional algebras representing elements in the brauer group bq ( k, h _ 4 ) of sweedler hopf algebra h _ 4 over a field k. they allow us to describe the mutual intersection of the subgroups arising from a quasitriangular or coquasitriangular structure. we also introduce a new subgroup of bq ( k, h _ 4 ) whose elements are represented by algebras for which the two natural z _ 2 - gradings coincide. we construct an exact sequence relating this subgroup to the brauer group of nichols 8 - dimensional hopf algebra e ( 2 ) with respect to the quasitriangular structure attached to the 2x2 - matrix n with 1 in the ( 1, 2 ) - entry and zero elsewhere. | arxiv:0904.1883 |
in math. rt / 0205144 we observed that, on the level of derived categories, representations of the lie algebra of a semisimple algebraic group over a field of finite characteristic with a given ( generalized ) regular central character can be identified with coherent sheaves on the formal neighborhood of the corresponding ( generalized ) springer fiber. in the present paper we treat singular central characters. the basic step is the beilinson - bernstein localization of modules with a fixed ( generalized ) central character as sheaves on the partial flag variety corresponding to the singularity of the character. these sheaves are modules over a sheaf of algebras which is a version of twisted crystalline differential operators, but is actually larger. we discuss translation functors and intertwining functors. the latter generate an action of the affine braid group on the derived category of modules with a regular ( generalized ) central character, which intertwines different localization functors. we also describe the standard duality on lie algebra modules in terms of d - modules and coherent sheaves. | arxiv:math/0602075 |
an accurate knowledge of nuclear parton distribution functions ( npdfs ) is an essential ingredient of high energy physics calculations when the processes are involving nuclei in the initial state. it is well known now that the prompt photon production both in hadronic and nuclear collisions is a powerful tool for exploring the parton densities in the nucleon and nuclei especially of the gluon. in this work, we are going to perform a comprehensive study of the isolated prompt photon production in $ p $ - pb collisions at backward rapidities to find the best kinematic regions in which the experimental measurements have most sensitivity to the nuclear modifications of parton densities. most emphasis will be placed on the antishadowing nuclear modification. to this aim, we calculate and compare various quantities at different values of center - of - mass energy covered by the lhc and also different rapidity regions to realize which one is most useful. | arxiv:1808.05639 |
we study the system of coupled atomic and molecular condensates within the two - mode model and beyond mean - field theory ( mft ). large amplitude atom - molecule coherent oscillations are shown to be damped by the rapid growth of fluctuations near the dynamically unstable molecular mode. this result contradicts earlier predictions about the recovery of atom - molecule oscillations in the two - mode limit. the frequency of the damped oscillation is also shown to scale as $ \ sqrt { n } / \ log n $ with the total number of atoms $ n $, rather than the expected pure $ \ sqrt { n } $ scaling. using a linearized model, we obtain analytical expressions for the initial depletion of the molecular condensate in the vicinity of the instability, and show that the important effect neglected by mean field theory is an initially non - exponential ` spontaneous ' dissociation into the atomic vacuum. starting with a small population in the atomic mode, the initial dissociation rate is sensitive to the exact atomic amplitudes, with the fastest ( super - exponential ) rate observed for the entangled state, formed by spontaneous dissociation. | arxiv:cond-mat/0105439 |
, founder alexandr wang ( drop - out ) texas instruments, 1930, founder cecil howard green ( sb, sm ) tsmc, 1987, founder morris chang ( sb, sm ) vmware, 1998, co - founder diane greene ( sm ) = = traditions and student activities = = the faculty and student body place a high value on meritocracy and on technical proficiency. mit has never awarded an honorary degree, nor does it award athletic scholarships, ad eundem degrees, or latin honors upon graduation. however, mit has twice awarded honorary professorships : to winston churchill in 1949 and salman rushdie in 1993. many upperclass students and alumni wear a large, heavy, distinctive class ring known as the " brass rat ". originally created in 1929, the ring ' s official name is the " standard technology ring ". the undergraduate ring design ( a separate graduate student version exists as well ) varies slightly from year to year to reflect the unique character of the mit experience for that class, but always features a three - piece design, with the mit seal and the class year each appearing on a separate face, flanking a large rectangular bezel bearing an image of a beaver. the initialism ihtfp, representing the informal school motto " i hate this fucking place " and jocularly euphemized as " i have truly found paradise ", " institute has the finest professors ", " institute of hacks, tomfoolery and pranks ", " it ' s hard to fondle penguins ", and other variations, has occasionally been featured on the ring given its historical prominence in student culture. = = = caltech rivalry = = = mit also shares a well - known rivalry with the california institute of technology ( caltech ), stemming from both institutions ' reputations as two of the highest ranked and most highly recognized science and engineering schools in the world. the rivalry is an unusual college rivalry given its focus on academics and pranks instead of sports, and due to the geographic distance between the two ( their campuses are separated by about 2580 miles and are on opposite coasts of the united states ). in 2005, caltech students pranked mit ' s campus preview weekend by distributing t - shirts that read " mit " on the front, and "... because not everyone can go to caltech " on the back. additionally, the word massachusetts in the " massachusetts institute of technology " engraving on the exterior of the lobby 7 dome was covered with a banner so that it read " that other institute | https://en.wikipedia.org/wiki/Massachusetts_Institute_of_Technology |
deep near - ir images from the vvv survey were used to search for rr lyrae type ab ( rrab ) stars within 100 ' from the galactic centre ( gc ). a sample of 960 rrab stars were discovered. we use the reddening - corrected magnitudes in order to isolate rrab belonging to the gc. the mean period for our rrab sample is $ p = 0. 5446 $ days, yielding a mean metallicity of $ [ fe / h ] = - 1. 30 $ dex and a median distance from the sun of $ d = 8. 05 $. we measure the rrab surface density using the less reddened region sampled here, finding $ 1000 $ rrab / sq deg at a projected galactocentric distance $ r _ g = 1. 6 $ deg. this implies a large total mass ( $ m > 10 ^ 9 m _ \ odot $ ) for the old and metal - poor population contained inside $ r _ g $. we measure accurate relative proper motions, from which we derive tangential velocity dispersions of $ \ sigma v _ l = 125. 0 $ and $ \ sigma v _ b = 124. 1 $ km / s along the galactic longitude and latitude coordinates, respectively. the fact that these quantities are similar indicate that the bulk rotation of the rrab population is negligible, and implies that this population is supported by velocity dispersion. there are two main conclusions of this study. first, the population as a whole is no different from the outer bulge rrab, predominantly a metal - poor component that is shifted respect the oosterhoff type i population defined by the globular clusters in the halo. second, the rrab sample, as representative of the old and metal - poor stellar population in the region, have high velocity dispersions and zero rotation, suggesting a formation via dissipational collapse. | arxiv:1807.04303 |
we study the potential of a neutrino factory in constraining the parameter space of a scheme with one sterile neutrino separated from three active ones by an o ( 1 ) ev ^ 2, mass - squared difference. we present approximated analytic expressions for the oscillation probabilities, showing that the greatest sensitivity to sterile neutrinos at a neutrino factory can be achieved using the \ nu _ \ mu - > \ nu _ \ mu and the \ nu _ \ mu - > \ nu _ \ tau oscillations. we have studied two setups : a neutrino factory with 50 gev ( 20 gev ) stored muons, with two detectors of the hybrid - mind type ( a magnetized ecc next to a magnetized iron calorimeter ), located at l = 3000, 7500 km ( l = 4000, 7500 km ) from the source. four channels have been used : \ nu _ e - > \ nu _ \ mu, \ nu _ \ tau ; \ nu _ \ mu - > \ nu _ \ mu, \ nu _ \ tau. the relevant backgrounds, efficiencies and systematic errors have been taken into account, and we have discussed dependence of the sensitivities on the systematic errors. we have found that the 50 gev ( 20 gev ) setup can constrain \ sin ^ 2 2 \ theta ^ { ( 4fam ) } _ { 13 } < = 7x10 ^ { - 5 } ( 2x10 ^ { - 4 } ) ; \ theta _ { 34 } < = 12 deg ( 14 deg ) ; and \ theta _ { 24 } < = 7. 5 deg ( 8 deg ). our results hold for any value of \ delta m ^ 2 _ { sbl } > ~ 0. 1 ev ^ 2. eventually we have shown that, if a positive signal is found, the proposed setup is able to measure simultaneously \ theta _ { 34 } and \ delta _ 3 with a precision of few degrees and few tens of degrees, respectively, solving the so - called " intrinsic " and " sign degeneracies ". combination of \ nu _ \ mu disappearance and of the \ nu _ \ mu - > \ nu _ \ tau channel, that will be called " the discovery channel ", at the two baselines is able to measure at 99 % cl a new cp - violating phase \ delta _ 3 for \ sin ^ 2 2 \ | arxiv:0812.3703 |
segment anything model ( sam ) is one of the pioneering prompt - based foundation models for image segmentation and has been rapidly adopted for various medical imaging applications. however, in clinical settings, creating effective prompts is notably challenging and time - consuming, requiring the expertise of domain specialists such as physicians. this requirement significantly diminishes sam ' s primary advantage, its interactive capability with end users, in medical applications. moreover, recent studies have indicated that sam, originally designed for 2d natural images, performs suboptimally on 3d medical image segmentation tasks. this subpar performance is attributed to the domain gaps between natural and medical images and the disparities in spatial arrangements between 2d and 3d images, particularly in multi - organ segmentation applications. to overcome these challenges, we present a novel technique termed autoprosam. this method automates 3d multi - organ ct - based segmentation by leveraging sam ' s foundational model capabilities without relying on domain experts for prompts. the approach utilizes parameter - efficient adaptation techniques to adapt sam for 3d medical imagery and incorporates an effective automatic prompt learning paradigm specific to this domain. by eliminating the need for manual prompts, it enhances sam ' s capabilities for 3d medical image segmentation and achieves state - of - the - art ( sota ) performance in ct - based multi - organ segmentation tasks. the code is in this { \ href { https : / / github. com / chengyinlee / autoprosam _ 2024 } { link } }. | arxiv:2308.14936 |
using a density matrix formulation for the effective action, we obtain a set of macroscopic equations that describe spin accumulation in a non - homogeneous ferromagnet. we give a new expression for the spin current which extends previous work by taking into account the symmetry of the ferromagnetic state through a careful treatment of the exchange term between the conduction electrons and the magnetization, i. e, d - electrons. we consider a simple application which has been discussed previously and show that in this case spin accumulation is an interface effect confirming earlier results arrived at by different methods. | arxiv:cond-mat/0407051 |
in a recent paper it has been shown that to model a diffusive molecular communication ( mc ) channel with multiple fully absorbing ( fa ) receivers, these can be interpreted as sources of negative particles from the other receivers ' perspective. the barycenter point is introduced as the best position where to place the negative sources. the barycenter is obtained from the spatial mean of the molecules impinging on the surface of each fa receiver. this paper derives an expression that captures the position of the barycenter in a diffusive mc channel with multiple fa receivers. in this work, an analytical model inspired by newton ' s law of gravitation is found to describe the barycenter, and the result is compared with particle - based simulation ( pbs ) data. since the barycenter depends on the distance between the transmitter and receiver and the observation time, the condition that the barycenter can be assumed to be at the center of the receiver is discussed. this assumption simplifies further modeling of any diffusive mc system containing multiple fa receivers. the resulting position of the barycenter is used in channel models to calculate the cumulative number of absorbed molecules and it has been verified with pbs data in a variety of scenarios. | arxiv:2304.13640 |
in this paper, we study the class of tempered distributions whose fourier transform is a translation bounded measure and show that each such distribution in $ \ mathbb { r } ^ d $ has order at most $ 2d $. we show the existence of the generalized eberlein decomposition within this class of distributions, and its compatibility with all previous eberlein decompositions. the generalized eberlein decomposition for fourier transformable measures and properties of its components are discussed. lastly, we take a closer look at the absolutely continuous spectrum of measures supported on meyer sets. | arxiv:2105.03382 |
top - emission quantum dot light - emitting diodes ( qleds ) have been extensively studied due to their potential application in augmented / virtual reality. particularly, the impact of fabry - p \ ' erot resonance on top - emission qleds has been investigated through both experimental and theoretical studies. additionally, multi - beam interference effects in qled emission layers have been explored theoretically. however, previous studies predominantly rely on simplified simulations or governing equations with minor numerical corrections, often resulting in discrepancies between theoretical predictions and experimental results. notably, a comprehensive investigation of multi - beam interference effects remains insufficient. this study aims to perform a theoretical analysis of multi - beam interference, substantiated with numerical simulations. specifically, we examine fabry - p \ ' erot resonance effects and compare them with interference between upward and downward emission components in qled layers. the findings are expected to provide insights into designing more efficient qled architectures. | arxiv:2503.13924 |
bismuth has recently attracted interest in connection with na - ion battery anodes due to its high volumetric capacity. it reacts with na to form na $ _ 3 $ bi which is a prototypical dirac semimetal with a nontrivial electronic structure. density - functional - theory based first - principles calculations are playing a key role in understanding the fascinating electronic structure of na $ _ 3 $ bi and other topological materials. in particular, the strongly - constrained - and - appropriately - normed ( scan ) meta - generalized - gradient - approximation ( meta - gga ) has shown significant improvement over the widely used generalized - gradient - approximation ( gga ) scheme in capturing energetic, structural, and electronic properties of many classes of materials. here, we discuss the electronic structure of na $ _ 3 $ bi within the scan framework and show that the resulting fermi velocities and { \ it s } - band shift around the $ \ gamma $ point are in better agreement with experiments than the corresponding gga predictions. scan yields a purely spin - orbit - coupling ( soc ) driven dirac semimetal state in na $ _ 3 $ bi in contrast with the earlier gga results. our analysis reveals the presence of a topological phase transition from the dirac semimetal to a trivial band insulator phase in na $ _ { 3 } $ bi $ _ { x } $ sb $ _ { 1 - x } $ alloys as the strength of the soc varies with sb content, and gives insight into the role of the soc in modulating conduction properties of na $ _ 3 $ bi. | arxiv:2006.08585 |
we describe advice derived from one of the largest development programs in norway, where twelve scrum teams combined agile practices with traditional project management. the perform program delivered 12 releases over a four - year period, and finished on budget and on time. in this article, we summarize 12 key lessons on five crucial topics, relevant to other large development projects seeking to combine scrum with traditional project management. | arxiv:1802.05118 |
we carry out the cantor - bendixson analysis of the space of all subgroups of any countable abelian group and we deduce a complete classification of such spaces up to homeomorphism. | arxiv:0811.1549 |
we study the structure of electromagnetic field of slowly rotating magnetized star in a randall - sundrum ii type braneworld. the star is modeled as a sphere consisting of perfect highly magnetized fluid with infinite conductivity and frozen - in dipolar magnetic field. maxwell ' s equations for the external magnetic field of the star in the braneworld are analytically solved in approximation of small distance from the surface of the star. we have also found numerical solution for the electric field outside the rotating magnetized neutron star in the braneworld in dependence on brane tension. the influence of brane tension on the electromagnetic energy losses of the rotating magnetized star is underlined. obtained " brane " corrections are shown to be relevant and have non - negligible values. in comparison with astrophysical observations on pulsars spindown data they may provide an evidence for the brane tension and, thus, serve as a test for the braneworld model of the universe. | arxiv:1012.2190 |
this work focuses on multidimensional summation - by - parts ( sbp ) discretizations of linear elliptic operators with variable coefficients. we consider a general sbp discretization with dense simultaneous approximation terms ( sats ), which serve as interior penalties to enforce boundary conditions and inter - element coupling in a weak sense. through the analysis of adjoint consistency and stability, we present several conditions on the sat penalties. based on these conditions, we generalize the modified scheme of bassi and rebay ( br2 ) and the symmetric interior penalty galerkin ( sipg ) method to sbp - sat discretizations. numerical experiments are carried out on unstructured grids with triangular elements to verify the theoretical results. | arxiv:1612.08106 |
we show a combinatorial formula for a lower bound of the dimension of the non - unipotent monodromy part of the first milnor cohomology of a hyperplane arrangement satisfying some combinatorial conditions. this gives exactly its dimension if a stronger combinatorial condition is satisfied. we also prove a non - combinatorial formula for the dimension of the non - unipotent part of the first milnor cohomology, which apparently depends on the position of the singular points. the latter generalizes a formula previously obtained by the second named author. | arxiv:0905.1284 |
this paper is devoted to the asymptotic analysis of the eigenvalues of the laplace operator with a strong magnetic field and robin boundary condition on a smooth planar domain and with a negative boundary parameter. we study the singular limit when the robin parameter tends to infinity which is equivalent to a semi - classical limit involving a small positive semi - classical parameter. the main result is a comparison between the spectrum of the robin laplacian with an effective operator defined on the boundary of the domain via the born - oppenheimer approximation. more precisely, the low - lying eigenvalue of the robin laplacian is approximated by the those of the effective operator. when the curvature has a unique non - degenerate maximum, we estimate the spectral gap and find that the magnetic field does not contribute to the three - term expansion of the eigenvalues. in the case of the disc domains, the eigenvalue asymptotics displays the contribution of the magnetic field explicitly. | arxiv:2111.01416 |
a novel effect of population transfer in a five - level system is analyzed. this population transfer effect is found to be a version of a raman process, which is facilitated and assisted by coherence effects, acting to close other available decay channels. | arxiv:quant-ph/0407191 |
we show that it is possible to uniquely reconstruct a generic many - body local hamiltonian from a single pair of initial and final states related by time evolution with the hamiltonian. we then propose a practical version of the protocol involving multiple pairs of such initial / final states. using the eigenstate thermalization hypothesis, we provide bounds on the protocol ' s performance and stability against errors from measurements and in the ansatz of the hamiltonian. the protocol is efficient ( requiring experimental resources scaling polynomially with system size in general and constant with system size given translation symmetry ) and thus enables analog and digital quantum simulators to verify implementation of a putative hamiltonian. | arxiv:1912.09492 |
we prove that morse local - to - global groups grow exponentially faster than their infinite index stable subgroups. this generalizes a result of dahmani, futer, and wise in the context of quasi - convex subgroups of hyperbolic groups to a broad class of groups that contains the mapping class group, cat ( 0 ) groups, and the fundamental groups of closed 3 - manifolds. to accomplish this, we develop a theory of automatic structures on morse geodesics in morse local - to - global groups. other applications of these automatic structures include a description of stable subgroups in terms of regular languages, rationality of the growth of stable subgroups, density in the morse boundary of the attracting fixed points of morse elements, and containment of the morse boundary inside the limit set of any infinite normal subgroup. | arxiv:2008.06379 |
this paper studies multilateral matching in which agents may negotiate contracts within any coalition. we assume scale economies such that an agent substitutes some existing contracts with new ones only if the latter involve a set of partners that is weakly larger than the original. a weakly setwise stable ( or setwise stable ) outcome exists and can be found by a constrained serial dictatorship algorithm in markets with scale economies ( resp. ordinal scale economies ). the scale economies condition applies to an environment in which agents cooperate to achieve targets, such as markets in which countries sign bilateral agreements. | arxiv:2310.19479 |
we present a trefftz - type finite element method on meshes consisting of curvilinear polygons. local basis functions are computed using integral equation techniques that allow for the efficient and accurate evaluation of quantities needed in the formation of local stiffness matrices. to define our local finite element spaces in the presence of curved edges, we must also properly define what it means for a function defined on a curved edge to be " polynomial " of a given degree on that edge. we consider two natural choices, before settling on the one that yields the inclusion of complete polynomial spaces in our local finite element spaces, and discuss how to work with these edge polynomial spaces in practice. an interpolation operator is introduced for the resulting finite elements, and we prove that it provides optimal order convergence for interpolation error under reasonable assumptions. we provide a description of the integral equation approach used for the examples in this paper, which was recently developed precisely with these applications in mind. a few numerical examples illustrate this optimal order convergence of the finite element solution on some families of meshes in which every element has at least one curved edge. we also demonstrate that it is possible to exploit the approximation power of locally singular functions that may exist in our finite element spaces in order to achieve optimal order convergence without the typical adaptive refinement toward singular points. | arxiv:1906.09015 |
using $ ( 448. 1 \ pm 2. 9 ) \ times 10 ^ { 6 } $ $ \ psi ( 3686 ) $ events collected with the besiii detector, we perform the first search for the weak baryonic decay $ \ psi ( 3686 ) \ to \ lambda _ c ^ { + } \ bar { \ sigma } ^ - + c. c. $. the analysis procedure is optimized using a blinded method. no significant signal is observed, and the upper limit on the branching fraction ( $ \ mathcal b $ ) of $ \ psi ( 3686 ) \ to \ lambda _ c ^ { + } \ bar { \ sigma } ^ - + c. c. $ is set to be $ 1. 4 \ times 10 ^ { - 5 } $ at the 90 \ % confidence level. | arxiv:2207.10877 |
implementations of cryptographic libraries have been scrutinized for secret - dependent execution behavior exploitable by microarchitectural side - channel attacks. to prevent unintended leakages, most libraries moved to constant - time implementations of cryptographic primitives. there have also been efforts to certify libraries for use in sensitive areas, like microsoft cng and botan, with specific attention to leakage behavior. in this work, we show that a common oversight in these libraries is the existence of \ emph { utility functions }, which handle and thus possibly leak confidential information. we analyze the exploitability of base64 decoding functions across several widely used cryptographic libraries. base64 decoding is used when loading keys stored in pem format. we show that these functions by themselves leak sufficient information even if libraries are executed in trusted execution environments. in fact, we show that recent countermeasures to transient execution attacks such as lvi \ emph { ease } the exploitability of the observed faint leakages, allowing us to robustly infer sufficient information about rsa private keys \ emph { with a single trace }. we present a complete attack, including a broad library analysis, a high - resolution last level cache attack on sgx enclaves, and a fully parallelized implementation of the extend - and - prune approach that allows a complete key recovery at medium costs. | arxiv:2108.04600 |
the degree to which mexican immigrants in the u. s. are assimilating culturally has been widely debated. to examine this question, we focus on musical taste, a key symbolic resource that signals the social positions of individuals. we adapt an assimilation metric from earlier work to analyze self - reported musical interests among immigrants in facebook. we use the relative levels of interest in musical genres, where a similarity to the host population in musical preferences is treated as evidence of cultural assimilation. contrary to skeptics of mexican assimilation, we find significant cultural convergence even among first - generation immigrants, which problematizes their use as assimilative " benchmarks " in the literature. further, 2nd generation mexican americans show high cultural convergence vis - \ ` a - vis both anglos and african - americans, with the exception of those who speak spanish. rather than conforming to a single assimilation path, our findings reveal how mexican immigrants defy simple unilinear theoretical expectations and illuminate their uniquely heterogeneous character. | arxiv:1902.09453 |
the super - hamiltonian of 4 - dimensional gravity as simplified by ashtekar through the use of gauge potential and densitized triad variables can furthermore be succinctly expressed as a poisson bracket between the volume element and other fundamental gauge - invariant elements of 3 - geometry. this observation naturally suggests a reformulation of non - perturbative quantum gravity wherein the wheeler - dewitt equation is identical to the requirement of the vanishing of the corresponding commutator. moreover, this reformulation singles out spin network states as the preeminent basis for expansion of all physical states. | arxiv:gr-qc/0512025 |
in this paper, we use characteristic classes of the canonical vector bundles and the poincar \ ' { e } dualality to study the structure of the real homology and cohomology groups of oriented grassmann manifold $ g ( k, n ) $. show that for $ k = 2 $ or $ n \ leq 8 $, the cohomology groups $ h ^ * ( g ( k, n ), { \ bf r } ) $ are generated by the first pontrjagin class, the euler classes of the canonical vector bundles. in these cases, the poincar \ ' { e } dualality : $ h ^ q ( g ( k, n ), { \ bf r } ) \ to h _ { k ( n - k ) - q } ( g ( k, n ), { \ bf r } ) $ can be given explicitly. | arxiv:0809.0808 |
the influence of gapless dissipative degrees of freedom on the superconductor - insulator transition in two dimensions is investigated. we develop a series expansion for the free energy of a ( 2 + 1 ) - dimensional xy model coupled to a bosonic heat bath that can be approximately summed to all orders. the calculation explicitly conserves topological excitations. we derive the zero temperature phase diagram and the free energy critical exponent, and find a transition from universal to non - universal scaling behavior as the coupling to the dissipative environment is increased, implying the existence of a new universality class. | arxiv:cond-mat/9911473 |
we introduce a type $ b $ analogue of the nil temperley - lieb algebra in terms of generators and relations, that we call the ( extended ) nil - blob algebra. we show that this algebra is isomorphic to the endomorphism algebra of a bott - samelson bimodule in type $ \ tilde { a } _ 1 $. we also prove that it is isomorphic to an idempotent truncation of the classical blob algebra. thus we provide strong evidence in favor of the recent blob vs. soergel conjecture. | arxiv:2001.00073 |
with the advent of network function virtualization ( nfv ), network services that traditionally run on proprietary dedicated hardware can now be realized using virtual network functions ( vnfs ) that are hosted on general - purpose commodity hardware. this new network paradigm offers a great flexibility to internet service providers ( isps ) for efficiently operating their networks ( collecting network statistics, enforcing management policies, etc. ). however, introducing nfv requires an investment to deploy vnfs at certain network nodes ( called vnf - nodes ), which has to account for practical constraints such as the deployment budget and the vnf - node capacity. to that end, it is important to design a joint vnf - nodes placement and capacity allocation algorithm that can maximize the total amount of network flows that are fully processed by the vnf - nodes while respecting such practical constraints. in contrast to most prior work that often neglects either the budget constraint or the capacity constraint, we explicitly consider both of them. we prove that accounting for these constraints introduces several new challenges. specifically, we prove that the studied problem is not only np - hard but also non - submodular. to address these challenges, we introduce a novel relaxation method such that the objective function of the relaxed placement subproblem becomes submodular. leveraging this useful submodular property, we propose two algorithms that achieve an approximation ratio of $ \ frac { 1 } { 2 } ( 1 - 1 / e ) $ and $ \ frac { 1 } { 3 } ( 1 - 1 / e ) $ for the original non - relaxed problem, respectively. finally, we corroborate the effectiveness of the proposed algorithms through extensive evaluations using trace - driven simulations. | arxiv:1901.03931 |
state of the art optimisation passes for dependently typed languages can help erase the redundant information typical of invariant - rich data structures and programs. these automated processes do not dramatically change the structure of the data, even though more efficient representations could be available. using quantitative type theory, we demonstrate how to define an invariant - rich, typechecking time data structure packing an efficient runtime representation together with runtime irrelevant invariants. the compiler can then aggressively erase all such invariants during compilation. unlike other approaches, the complexity of the resulting representation is entirely predictable, we do not require both representations to have the same structure, and yet we are able to seamlessly program as if we were using the high - level structure. | arxiv:2301.02194 |
in this paper, we survey literature on prophet inequalities for subadditive combinatorial auctions. we give an overview of the previous best $ o ( \ log \ log m ) $ prophet inequality as well as the preceding $ o ( \ log m ) $ prophet inequality. then, we provide the constructive posted price mechanisms used in order to prove the two bounds. we mainly focus on the most recent literature that resolves a central open problem in this area of discovering a constant factor prophet inequality for subadditive valuations. we detail the approach of this new paper, which is $ \ textit { non - constructive } $ and therefore cannot be implemented using prices, as done in previous literature. | arxiv:2305.12698 |
the radiative acceleration of particles and the electrostatic potential fields that arise in low density plasmas hit by radiation produced by a transient, compact source are investigated. we calculate the dynamical evolution and asymptotic energy of the charged particles accelerated by the photons and the radiation - induced electric double layer in the full relativistic, klein - nishina regime. for fluxes in excess of $ 10 ^ { 27 } $ $ { \ rm erg } { \ rm cm } ^ { - 2 } { \ rm s } ^ { - 1 } $, the radiative force on a diluted plasma ( $ n \ la 10 ^ { 11 } $ cm $ ^ { - 3 } $ ) is so strong that electrons are accelerated rapidly to relativistic speeds while ions lag behind owing to their larger inertia. the ions are later effectively accelerated by the strong radiation - induced double layer electric field up to lorentz factors $ \ approx 100 $, attainable in the case of negligible compton drag. the asymptotic energies achieved by both ions and electrons are larger by a factor 2 - - 4 with respect to what one could naively expect assuming that the electron - ion assembly is a rigidly coupled system. the regime we investigate may be relevant within the framework of giant flares from soft gamma - repeaters. | arxiv:astro-ph/0304249 |
the first evidence for x ( 3872 ) production in relativistic heavy ion collisions is reported. the x ( 3872 ) production is studied in lead - lead ( pbpb ) collisions at a center - of - mass energy of $ \ sqrt { s _ \ mathrm { nn } } = $ 5. 02 tev per nucleon pair, using the decay chain x ( 3872 ) $ \ to $ j $ / \ psi \, \ pi ^ + \ pi ^ - \ to $ $ \ mu ^ + \ mu ^ - \ pi ^ + \ pi ^ - $. the data were recorded with the cms detector in 2018 and correspond to an integrated luminosity of 1. 7 nb $ ^ { - 1 } $. the measurement is performed in the rapidity and transverse momentum ranges $ | y | $ $ \ lt $ 1. 6 and 15 $ \ lt $ $ p _ \ mathrm { t } $ $ \ lt $ 50 gev $ / c $. the significance of the inclusive x ( 3872 ) signal is 4. 2 standard deviations. the prompt x ( 3872 ) to $ \ psi $ ( 2s ) yield ratio is found to be $ \ rho ^ \ mathrm { pbpb } = $ 1. 08 $ \ pm $ 0. 49 ( stat ) $ \ pm $ 0. 52 ( syst ), to be compared with typical values of 0. 1 for pp collisions. this result provides a unique experimental input to theoretical models of the x ( 3872 ) production mechanism, and of the nature of this exotic state. | arxiv:2102.13048 |
low - ionization - state far - infrared ( fir ) emission lines may be useful diagnostics of star - formation activity in young galaxies, and at high redshift may be detectable from the ground. in practice, however, very little is known concerning how strong such line emission might be in the early universe. we attempted to detect the 158 micron [ c ii ] line from a lensed galaxy at z = 4. 926 using the caltech submillimeter observatory. this source is an ordinary galaxy, in the sense that it shows high but not extreme star formation, but lensing makes it visible. our analysis includes a careful consideration of the calibrations and weighting of the individual scans. we find only modest improvement over the simpler reduction methods, however, and the final spectrum remains dominated by systematic baseline ripple effects. we obtain a 95 per cent confidence upper limit of 33 mjy for a 200 km / s full width at half maximum line, corresponding to an unlensed luminosity of 1x10 ^ 9 l _ sun for a standard cosmology. combining this with a marginal detection of the continuum emission using the james clerk maxwell telescope, we derive an upper limit of 0. 4 per cent for the ratio of l _ cii / l _ fir in this object. | arxiv:astro-ph/0503054 |
gravity and thermal energy are universal phenomena which compete over the stabilization of astrophysical systems. the former induces an inward pressure driving collapse and the latter a stabilizing outward pressure generated by random motion and energy dispersion. since a contracting self - gravitating system is heated up one may wonder why is gravitational collapse not halted in all cases at a sufficient high temperature establishing either a gravo - thermal equilibrium or explosion. here, based on the equivalence between mass and energy, we show that there always exists a temperature threshold beyond which the gravitation of thermal energy overcomes its stabilizing pressure and the system collapses under the weight of its own heat. | arxiv:2009.11919 |
the monograph contains the detailed exposition of the results obtained by the author during the last several years. in particular it contains an improvement of the well known calderon - ryff interpolation theorem and description of " verifying " operators of conditional mathematical expectations { if such an operator leaves an order ideal in $ l ^ 1 % invariant, then the ideal is an interpolation space }. | arxiv:1803.09796 |
we study stable matching problems in networks where players are embedded in a social context, and may incorporate friendship relations or altruism into their decisions. each player is a node in a social network and strives to form a good match with a neighboring player. we consider the existence, computation, and inefficiency of stable matchings from which no pair of players wants to deviate. when the benefits from a match are the same for both players, we show that incorporating the well - being of other players into their matching decisions significantly decreases the price of stability, while the price of anarchy remains unaffected. furthermore, a good stable matching achieving the price of stability bound always exists and can be reached in polynomial time. we extend these results to more general matching rewards, when players matched to each other may receive different utilities from the match. for this more general case, we show that incorporating social context ( i. e., " caring about your friends " ) can make an even larger difference, and greatly reduce the price of anarchy. we show a variety of existence results, and present upper and lower bounds on the prices of anarchy and stability for various matching utility structures. finally, we extend most of our results to network contribution games, in which players can decide how much effort to contribute to each incident edge, instead of simply choosing a single node to match with. | arxiv:1204.5780 |
we consider inelastic dark matter scenarios with dark photon mediator and a dark higgs boson. the dark higgs boson spontaneously breaks the gauge symmetry associated with the dark photon, and gives the mass to the dark photon and the mass difference to dark particles. such a dark higgs boson can decay into the dark particles and hence can be another source of the dark particles at collider experiments. we analyze the sensitivity to decays of the excited state into the dark matter and charged particles at the faser 2 experiment in fermion and scalar inelastic dark matter scenarios. we consider two mass spectra as illustrating examples in which the excited state can be produced only through the decay of dark higgs boson. we show that unprobed parameter region can be explored in fermion dark matter scenario for the illustrating mass spectra. | arxiv:2112.12432 |
this paper describes our two - stage system for the euphemism detection shared task hosted by the 3rd workshop on figurative language processing in conjunction with emnlp 2022. euphemisms tone down expressions about sensitive or unpleasant issues like addiction and death. the ambiguous nature of euphemistic words or expressions makes it challenging to detect their actual meaning within a context. in the first stage, we seek to mitigate this ambiguity by incorporating literal descriptions into input text prompts to our baseline model. it turns out that this kind of direct supervision yields remarkable performance improvement. in the second stage, we integrate visual supervision into our system using visual imageries, two sets of images generated by a text - to - image model by taking terms and descriptions as input. our experiments demonstrate that visual supervision also gives a statistically significant performance boost. our system achieved the second place with an f1 score of 87. 2 %, only about 0. 9 % worse than the best submission. | arxiv:2211.04576 |
the method recently developed to include van der waals interactions in the density functional theory by using the maximally - localized wannier functions, is improved and extended to the case of atoms and fragments weakly bonded ( physisorbed ) to metal and semimetal surfaces, thus opening the way to realistic simulations of surface - physics processes, where van der waals interactions play a key role. successful applications to the case of ar on graphite and on the al ( 100 ) surface, and of the h2 molecule on al ( 100 ) are presented. | arxiv:0809.1491 |
it is shown that phenomenologically favorable expressions of quark mixing angles through the ratios of current quark masses may be derived as stable points of certain 4 - th power in ckm matrix flavor - invariant potentials built with traces of 3x3 quark up and down mass matrices. | arxiv:2210.09780 |
self - testing protocols enable certification of quantum devices without demanding full knowledge about their inner workings. a typical approach in designing such protocols is based on observing nonlocal correlations which exhibit maximum violation in a bell test. we show that in bell experiment known as hardy ' s test of nonlocality not only the maximally nonlocal correlation self - tests a quantum state, rather a non - maximal nonlocal behavior can serve the same purpose. we, in fact, completely characterize all such behaviors leading to self - test of every pure two qubit entangled state except the maximally entangled ones. apart from originating a novel self - testing protocol, our method provides a powerful tool towards characterizing the complex boundary of the set of quantum correlations. | arxiv:2112.06595 |
let $ e $ be a finite directed graph with no sources or sinks and write $ x _ e $ for the graph correspondence. we study the $ c ^ * $ - algebra $ c ^ * ( e, z ) : = \ mathcal { t } ( x _ e, z ) / \ mathcal { k } $ where $ \ mathcal { t } ( x _ e, z ) $ is the $ c ^ * $ - algebra generated by weighted shifts on the fock correspondence $ \ mathcal { f } ( x _ e ) $ given by a weight sequence $ \ { z _ k \ } $ of operators $ z _ k \ in \ mathcal { l } ( x _ { e ^ { k } } ) $ and $ \ mathcal { k } $ is the algebra of compact operators on the fock correspondence. if $ z _ k = i $ for every $ k $, $ c ^ * ( e, z ) $ is the cuntz - krieger algebra associated with the graph $ e $. we show that $ c ^ * ( e, z ) $ can be realized as a cuntz - pimsner algebra and use a result of schweizer to find conditions for the algebra $ c ^ * ( e, z ) $ to be simple. we also analyse the gauge - invariant ideals of $ c ^ * ( e, z ) $ using a result of katsura and conditions that generalize the conditions of subsets of $ e ^ 0 $ ( the vertices of $ e $ ) to be hereditary or saturated. as an example, we discuss in some details the case where $ e $ is a cycle. | arxiv:2108.05601 |
existing text - to - image models still struggle to generate images of multiple objects, especially in handling their spatial positions, relative sizes, overlapping, and attribute bindings. to efficiently address these challenges, we develop a training - free multimodal - llm agent ( mulan ), as a human painter, that can progressively generate multi - object with intricate planning and feedback control. mulan harnesses a large language model ( llm ) to decompose a prompt to a sequence of sub - tasks, each generating only one object by stable diffusion, conditioned on previously generated objects. unlike existing llm - grounded methods, mulan only produces a high - level plan at the beginning while the exact size and location of each object are determined upon each sub - task by an llm and attention guidance. moreover, mulan adopts a vision - language model ( vlm ) to provide feedback to the image generated in each sub - task and control the diffusion model to re - generate the image if it violates the original prompt. hence, each model in every step of mulan only needs to address an easy sub - task it is specialized for. the multi - step process also allows human users to monitor the generation process and make preferred changes at any intermediate step via text prompts, thereby improving the human - ai collaboration experience. we collect 200 prompts containing multi - objects with spatial relationships and attribute bindings from different benchmarks to evaluate mulan. the results demonstrate the superiority of mulan in generating multiple objects over baselines and its creativity when collaborating with human users. the code is available at https : / / github. com / measure - infinity / mulan - code. | arxiv:2402.12741 |
we review the current understanding of the upper atmospheres of uranus and neptune, and explore the upcoming opportunities available to study these exciting planets. the ice giants are the least understood planets in the solar system, having been only visited by a single spacecraft, in 1986 and 1989, respectively. the upper atmosphere plays a critical role in connecting the atmosphere to the forces and processes contained within the magnetic field. for example, auroral current systems can drive charged particles into the atmosphere, heating it by way of joule heating. ground - based observations of h $ _ 3 ^ + $ provides a powerful remote diagnostic of the physical properties and processes that occur within the upper atmosphere, and a rich data set exists for uranus. these observations span almost three decades and have revealed that the upper atmosphere has continuously cooled between 1992 and 2018 at about 8 k / year, from $ \ sim $ 750 k to $ \ sim $ 500 k. the reason for this trend remain unclear, but could be related to seasonally driven changes in the joule heating rates due to the tilted and offset magnetic field, or could be related to changing vertical distributions of hydrocarbons. h $ _ 3 ^ + $ has not yet been detected at neptune, but this discovery provides low - hanging fruit for upcoming facilities such as the james webb space telescope ( jwst ) and the next generation of 30 metre telescopes. detecting h $ _ 3 ^ + $ at neptune would enable the characterisation of its upper atmosphere for the first time since 1989. to fully understand the ice giants we need dedicated orbital missions, in the same way the cassini spacecraft explored saturn. only by combining in - situ observations of the magnetic field with in - orbit remote sensing can we get the complete picture of how energy moves between the atmosphere and the magnetic field. | arxiv:2009.02071 |
a measurement of neutrinoless double beta decay in one isotope does not allow to determine the underlying physics mechanism. we discuss the discrimination of mechanisms for neutrinoless double beta decay by comparing ratios of half life measurements for different isotopes. six prominent examples for specific new physics contributions to neutrinoless double beta decay are analyzed. we find that the change in corresponding ratios of half lives varies from 60 % for supersymmetric models up to a factor of 5 - 20 for extra - dimensional and left - right - symmetric mechanisms. | arxiv:hep-ph/0612165 |
we show that a closed orientable riemannian $ n $ - manifold, $ n \ ge 5 $, with positive isotropic curvature and free fundamental group is homeomorphic to the connected sum of copies of $ s ^ { n - 1 } \ times s ^ 1 $. | arxiv:0801.2221 |
we investigate a method to deal with congestion of sectors and delays in the tactical phase of air traffic flow and capacity management. it relies on temporal objectives given for every point of the flight plans and shared among the controllers in order to create a collaborative environment. this would enhance the transition from the network view of the flow management to the local view of air traffic control. uncertainty is modeled at the trajectory level with temporal information on the boundary points of the crossed sectors and then, we infer the probabilistic occupancy count. therefore, we can model the accuracy of the trajectory prediction in the optimization process in order to fix some safety margins. on the one hand, more accurate is our prediction ; more efficient will be the proposed solutions, because of the tighter safety margins. on the other hand, when uncertainty is not negligible, the proposed solutions will be more robust to disruptions. furthermore, a multiobjective algorithm is used to find the tradeoff between the delays and congestion, which are antagonist in airspace with high traffic density. the flow management position can choose manually, or automatically with a preference - based algorithm, the adequate solution. this method is tested against two instances, one with 10 flights and 5 sectors and one with 300 flights and 16 sectors. | arxiv:1309.4085 |
we study six - dimensional n = ( 1, 0 ) supergravity theories with abelian, as well as non - abelian, gauge group factors. we show that for theories with fewer than nine tensor multiplets, the number of possible combinations of gauge groups - including abelian factors - and non - abelian matter representations is finite. we also identify infinite families of theories with distinct u ( 1 ) charges that cannot be ruled out using known quantum consistency conditions, though only a finite subset of these can arise from known string constructions. | arxiv:1110.5916 |
intergalactic magnetic fields in the voids of the large - scale structure can be probed via measurements of secondary gamma - ray emission from gamma - ray interactions with extragalactic background light. lower bounds on the magnetic field in the voids were derived from the non - detection of this emission. it is not clear a priori what kind of magnetic field is responsible for the suppression of the secondary gamma - ray flux : a cosmological magnetic field that might be filling the voids or the field spread by galactic winds driven by star formation and active galactic nuclei. we used illustristng cosmological simulations to study the effect of magnetized galactic wind bubbles on the secondary gamma - ray flux. we show that within the illustristng model of baryonic feedback, the galactic wind bubbles typically provide energy - independent secondary flux suppression at the level of about 10 %. the observed flux suppression effect has to be due to the cosmological magnetic field in the voids. this might not be the case for a special case when the primary gamma - ray source has a hard intrinsic gamma - ray spectrum that peaks in the energy range above 50 tev. in this case, the observational data may be strongly affected by the magnetized bubble that is blown by the source host galaxy. | arxiv:2106.02690 |
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