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we offer philosophical motivations for a method we call virtual world cognitive science ( vw cogsci ), in which researchers use virtual embodied agents that are embedded in virtual worlds to explore questions in the field of cognitive science. we focus on questions about mental and linguistic representation and the ways that such computational modeling can add rigor to philosophical thought experiments, as well as the terminology used in the scientific study of such representations. we find that this method forces researchers to take a god ' s - eye view when describing dynamical relationships between entities in minds and entities in an environment in a way that eliminates the need for problematic talk of belief and concept types, such as the belief that cats are silly, and the concept cat, while preserving belief and concept tokens in individual cognizers ' minds. we conclude with some further key advantages of vw cogsci for the scientific study of mental and linguistic representation and for cognitive science more broadly.
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arxiv:2405.08304
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we present an analytical computation of the asymptotic temporal behavior of the information geometric complexity ( igc ) of finite - dimensional gaussian statistical manifolds in the presence of microcorrelations ( correlations between microvariables ). we observe a power law decay of the igc at a rate determined by the correlation coefficient. it is found that microcorrelations lead to the emergence of an asymptotic information geometric compression of the statistical macrostates explored by the system at a faster rate than that observed in absence of microcorrelations. this finding uncovers an important connection between ( micro ) - correlations and ( macro ) - complexity in gaussian statistical dynamical systems.
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arxiv:1005.2292
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we have predicted the difference in inclusive cross sections on pseudorapidity in $ { \ rm d } \ sigma ^ { p \ bar { p } } / { \ rm d } \ eta $ and $ { \ rm d } \ sigma ^ { pp } / { \ rm d } \ eta $ interactions at $ \ sqrt { s } = 900 $ ~ gev. their ratio $ r = \ left ( { \ rm d } \ sigma ^ { p \ bar { p } } / { \ rm d } \ eta \ right ) \ left / \ left ( { \ rm d } \ sigma ^ { pp } / { \ rm d } \ eta \ right ) \ right. > 1 $ in the whole pseudorapidity range. on the basis of agk theorem we show that the ratio of inclusive cross sections of $ pp $ and $ p \ bar { p } $ at $ \ sqrt { s } = 900 $ ~ gev in the region of low transverse momenta $ p _ \ perp $ up to 2 ~ gev $ \ left ( \ frac { 1 } { 2 \ pi p _ \ perp } \ frac { { \ rm d } ^ 2 \ sigma ^ { p \ bar { p } } } { { \ rm d } \ eta { \ rm d } p _ \ perp } \ right ) \ left / \ left ( \ frac { 1 } { 2 \ pi p _ \ perp } \ frac { { \ rm d } ^ 2 \ sigma ^ { pp } } { { \ rm d } \ eta { \ rm d } p _ \ perp } \ right ) \ right. = r $. experimental measurements by the atlas coll. give value $ r \ simeq1. 2 $ for interval $ | \ eta | < 2. 5 $. the difference in inclusive cross sections results from presence of additional subprocess in $ p \ bar { p } $ - - hadrons production from decay of three quark strings, which is absent in $ pp $ scattering.
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arxiv:1010.5258
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in bhatt and roy ' s minimal directed spanning tree ( mdst ) construction for a random partially ordered set of points in the unit square, all edges must respect the ` ` coordinatewise ' ' partial order and there must be a directed path from each vertex to a minimal element. we study the asymptotic behaviour of the total length of this graph with power weighted edges. the limiting distribution is given by the sum of a normal component away from the boundary and a contribution introduced by the boundary effects, which can be characterized by a fixed point equation, and is reminiscent of limits arising in the probabilistic analysis of certain algorithms. as the exponent of the power weighting increases, the distribution undergoes a phase transition from the normal contribution being dominant to the boundary effects dominating. in the critical case where the weight is simple euclidean length, both effects contribute significantly to the limit law. we also give a law of large numbers for the total weight of the graph.
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arxiv:math/0409201
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the cosmological case for a next generation radio observatory, the square kilometer array, is discussed and reviewed. an instrument like the ska would be able to measure galaxy redshifts of normal late - type galaxies, via the 21 cm line of hi, out to redshifts of $ \ sim 3 $. not only would such very deep redshift surveys enable us to map the large scale galaxy distribution and probe the large scale structure of the universe out to previously unexplored scales, it would also allow for the first time to obtain direct observational data on the evolution of this structure. other promising applications concern the mapping of the local velocity field of the universe, study of the formation and evolution of galaxies, and determining the global cosmological parameters $ h _ 0 $, $ q _ 0 $ and $ \ lambda $ through the application of classical cosmological tests like source counts. particularly emphasized is the redshift survey capability of the ska. a review is given of the current knowledge of the galaxy distribution, starting from an inventarisation of nearby cosmic structures, through a discussion of how it all fits together in a coherent ` ` foamlike pattern ' '. after providing a short overview of the basics of theories of structure formation, a description is provided of different observational strategies to probe the structure of the universe out to larger depths, ranging from pencil - beam surveys and cluster surveys out to the new and ambitious complete and deep galaxy redshift surveys like the 2df and the sloan survey. it is argued that a survey with the ska would be a natural and complementary follow - up. we finally conclude with a specification of the technical requirements for the ska to make it into an instrument ideally suited for these purposes.
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arxiv:astro-ph/9602096
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we investigate a family of distributions having a property of stability - under - addition, provided that the number $ \ nu $ of added - up random variables in the random sum is also a random variable. we call the corresponding property a \, $ \ nu $ - stability and investigate the situation with the semigroup generated by the generating function of $ \ nu $ is commutative. using results from the theory of iterations of analytic functions, we show that the characteristic function of such a $ \ nu $ - stable distribution can be represented in terms of chebyshev polynomials, and for the case of $ \ nu $ - normal distribution, the resulting characteristic function corresponds to the hyperbolic secant distribution. we discuss some specific properties of the class and present particular examples.
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arxiv:1008.3150
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this paper reports progress in the development of comb magnet technology with star wires. a two - layer dipole magnet with 60 mm clear bore has been recently fabricated and tested in liquid nitrogen. the purpose of the test was to determine what kind of critical current degradation occurs in the process of winding the star wire into the comb structure.
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arxiv:2307.12954
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fashion analysis refers to the process of examining and evaluating trends, styles, and elements within the fashion industry to understand and interpret its current state, generating fashion reports. it is traditionally performed by fashion professionals based on their expertise and experience, which requires high labour cost and may also produce biased results for relying heavily on a small group of people. in this paper, to tackle the fashion report generation ( fashionregen ) task, we propose an intelligent fashion analyzing and reporting system based the advanced large language models ( llms ), debbed as gpt - far. specifically, it tries to deliver fashionregen based on effective catwalk analysis, which is equipped with several key procedures, namely, catwalk understanding, collective organization and analysis, and report generation. by posing and exploring such an open - ended, complex and domain - specific task of fashionregen, it is able to test the general capability of llms in fashion domain. it also inspires the explorations of more high - level tasks with industrial significance in other domains. video illustration and more materials of gpt - far can be found in https : / / github. com / compfashion / fashionregen.
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arxiv:2403.06660
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the field of oscillation physics is about to make an enormous leap forward in statistical precision : first through the minos experiment in the coming year, and later through the nova and t2k experiments. because of the relatively poor understanding of neutrino interactions in the energy ranges of these experiments, there are systematics that can arise in interpreting far detector data that can be as large as or even larger than the expected statistical uncertainties. we describe how these systematic errors arise, and how specific measurements in a dedicated neutrino scattering experiment like minerva can reduce the cross section systematic errors to well below the statistical errors.
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arxiv:hep-ex/0410005
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we construct an action selector on aspherical symplectic manifolds that are closed or convex. such selectors have been constructed by matthias schwarz using floer homology. the construction we present here is simpler and uses only gromov compactness.
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arxiv:1902.00731
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we consider a one dimensional l \ ' evy bridge x _ b of length n and index 0 < \ alpha < 2, i. e. a l \ ' evy random walk constrained to start and end at the origin after n time steps, x _ b ( 0 ) = x _ b ( n ) = 0. we compute the distribution p _ b ( a, n ) of the area a = \ sum _ { m = 1 } ^ n x _ b ( m ) under such a l \ ' evy bridge and show that, for large n, it has the scaling form p _ b ( a, n ) \ sim n ^ { - 1 - 1 / \ alpha } f _ \ alpha ( a / n ^ { 1 + 1 / \ alpha } ), with the asymptotic behavior f _ \ alpha ( y ) \ sim y ^ { - 2 ( 1 + \ alpha ) } for large y. for \ alpha = 1, we obtain an explicit expression of f _ 1 ( y ) in terms of elementary functions. we also compute the average profile < \ tilde x _ b ( m ) > at time m of a l \ ' evy bridge with fixed area a. for large n and large m and a, one finds the scaling form < \ tilde x _ b ( m ) > = n ^ { 1 / \ alpha } h _ \ alpha ( { m } / { n }, { a } / { n ^ { 1 + 1 / \ alpha } } ), where at variance with brownian bridge, h _ \ alpha ( x, y ) is a non trivial function of the rescaled time m / n and rescaled area y = a / n ^ { 1 + 1 / \ alpha }. our analytical results are verified by numerical simulations.
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arxiv:1004.5046
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in hindustani classical music, the tabla plays an important role as a rhythmic backbone and accompaniment. in applications like computer - based music analysis, learning singing, and learning musical instruments, tabla stroke transcription, $ t \ bar { a } la $ identification, and generation are crucial. this paper proposes a comprehensive system aimed at addressing these challenges. for tabla stroke transcription, we propose a novel approach based on model - agnostic meta - learning ( maml ) that facilitates the accurate identification of tabla strokes using minimal data. leveraging these transcriptions, the system introduces two novel $ t \ bar { a } la $ identification methods based on the sequence analysis of tabla strokes. \ par furthermore, the paper proposes a framework for $ t \ bar { a } la $ generation to bridge traditional and modern learning methods. this framework utilizes finite state transducers ( fst ) and linear time - invariant ( lti ) filters to generate $ t \ bar { a } las $ with real - time tempo control through user interaction, enhancing practice sessions and musical education. experimental evaluations on tabla solo and concert datasets demonstrate the system ' s exceptional performance on real - world data and its ability to outperform existing methods. additionally, the proposed $ t \ bar { a } la $ identification methods surpass state - of - the - art techniques. the contributions of this paper include a combined approach to tabla stroke transcription, innovative $ t \ bar { a } la $ identification techniques, and a robust framework for $ t \ bar { a } la $ generation that handles the rhythmic complexities of hindustani music.
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arxiv:2407.20935
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we examine theoretically the spreading of a viscous liquid drop over a thin film of uniform thickness, assuming the liquid ' s viscosity is regulated by the concentration of a solute that is carried passively by the spreading flow. the solute is assumed to be initially heterogeneous, having a spatial distribution with prescribed statistical features. to examine how this variability influences the drop ' s motion, we investigate spreading in a planar geometry using lubrication theory, combining numerical simulations with asymptotic analysis. we assume diffusion is sufficient to suppress solute concentration gradients across but not along the film. the solute field beneath the bulk of the drop is stretched by the spreading flow, such that the initial solute concentration immediately behind the drop ' s effective contact lines has a long - lived influence on the spreading rate. over long periods, solute swept up from the precursor film accumulates in a short region behind the contact line, allowing patches of elevated viscosity within the precursor film to hinder spreading. a low - order model provides explicit predictions of the variances in spreading rate and drop location, which are validated against simulations.
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arxiv:1608.05220
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this paper investigates the use of large language models ( llms ) for extracting sample lists of polymer nanocomposites ( pncs ) from full - length materials science research papers. the challenge lies in the complex nature of pnc samples, which have numerous attributes scattered throughout the text. the complexity of annotating detailed information on pncs limits the availability of data, making conventional document - level relation extraction techniques impractical due to the challenge in creating comprehensive named entity span annotations. to address this, we introduce a new benchmark and an evaluation technique for this task and explore different prompting strategies in a zero - shot manner. we also incorporate self - consistency to improve the performance. our findings show that even advanced llms struggle to extract all of the samples from an article. finally, we analyze the errors encountered in this process, categorizing them into three main challenges, and discuss potential strategies for future research to overcome them.
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arxiv:2403.00260
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we explore lattice structures on integer binary relations ( i. e. binary relations on the set $ \ { 1, 2, \ dots, n \ } $ for a fixed integer $ n $ ) and on integer posets ( i. e. partial orders on the set $ \ { 1, 2, \ dots, n \ } $ for a fixed integer $ n $ ). we first observe that the weak order on the symmetric group naturally extends to a lattice structure on all integer binary relations. we then show that the subposet of this weak order induced by integer posets defines as well a lattice. we finally study the subposets of this weak order induced by specific families of integer posets corresponding to the elements, the intervals, and the faces of the permutahedron, the associahedron, and some recent generalizations of those.
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arxiv:1701.07995
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bottomonium production in heavy ion collisions is modified compared with any simple extrapolation from elementary collisions. this modification is most likely caused by the presence of a deconfined system of quarks and gluons for times of several fm / c. in such a medium, bottomonium can be destroyed, but the constituent bottom quarks will likely stay spatially correlated due to small mean free paths in this system. with these facts in mind, we describe bottomonium formation with a coupled set of equations. a rate equation describes the destruction of $ \ upsilon ( 1s ) $ particles, while a langevin equation describes how the bottom quarks stay correlated for a sufficiently long time so that recombination into bottomonia is possible. we show that within this approach it is possible to understand the magnitude of $ \ upsilon ( 1s ) $ suppression in heavy ion collisions and the larger suppression of the $ \ upsilon ( 2s ) $ state, implying that the reduction in the ratio of $ \ upsilon ( 1s ) / \ upsilon ( 2s ) $ yield in heavy ion collision does not necessarily correspond to sequential melting picture.
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arxiv:1606.08421
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machine learning ( ml ) algorithms are vital for supporting clinical decision - making in biomedical informatics. however, their predictive performance can vary across demographic groups, often due to the underrepresentation of historically marginalized populations in training datasets. the investigation reveals widespread sex - and age - related inequities in chronic disease datasets and their derived ml models. thus, a novel analytical framework is introduced, combining systematic arbitrariness with traditional metrics like accuracy and data complexity. the analysis of data from over 25, 000 individuals with chronic diseases revealed mild sex - related disparities, favoring predictive accuracy for males, and significant age - related differences, with better accuracy for younger patients. notably, older patients showed inconsistent predictive accuracy across seven datasets, linked to higher data complexity and lower model performance. this highlights that representativeness in training data alone does not guarantee equitable outcomes, and model arbitrariness must be addressed before deploying models in clinical settings.
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arxiv:2412.19495
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we clarify the links between the graded specht construction of modules over cyclotomic hecke algebras and the rsk construction for quiver hecke algebras of type a, that was recently imported from the setting of representations of p - adic groups. for that goal we develop a theory of crystal derivative operators on quiver hecke algebra modules, that categorifies the berenstein - zelevinsky strings framework on quantum groups, and generalizes a graded variant of the classical bernstein - zelevinsky derivatives from the p - adic setting. graded cyclotomic decomposition numbers are shown to be a special subfamily of the wider concept of rsk decomposition numbers.
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arxiv:2110.11381
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domain generalization aims at learning a universal model that performs well on unseen target domains, incorporating knowledge from multiple source domains. in this research, we consider the scenario where different domain shifts occur among conditional distributions of different classes across domains. when labeled samples in the source domains are limited, existing approaches are not sufficiently robust. to address this problem, we propose a novel domain generalization framework called { wasserstein distributionally robust domain generalization } ( wdrdg ), inspired by the concept of distributionally robust optimization. we encourage robustness over conditional distributions within class - specific wasserstein uncertainty sets and optimize the worst - case performance of a classifier over these uncertainty sets. we further develop a test - time adaptation module leveraging optimal transport to quantify the relationship between the unseen target domain and source domains to make adaptive inference for target data. experiments on the rotated mnist, pacs and the vlcs datasets demonstrate that our method could effectively balance the robustness and discriminability in challenging generalization scenarios.
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arxiv:2207.04913
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we construct a new framework to calculate the enhancement of axion masses and concomitant effects on axion - meson mixing arising from small size instantons ( ssis ), which originate in models featuring an extended color gauge symmetry. the framework is based on an explicit evaluation of ' t hooft determinantal operators that partition into instanton amplitudes, affording a more precise determination of the axion - diphoton coupling than previous results. using an explicit model first presented in ref. arxiv : 1805. 06465, we demonstrate that axions solving the strong cp problem can have electroweak scale masses and higher, driven by ssi effects. such collider axions are prime targets for resonance searches at the large hadron collider and afford a unique anchor for motivating extended color symmetries.
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arxiv:2207.08740
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we study the effects of inertia in dense suspensions of polar swimmers. the hydrodynamic velocity field and the polar order parameter field describe the dynamics of the suspension. we show that a dimensionless parameter $ r $ ( ratio of the swimmer self - advection speed to the active stress invasion speed ) controls the stability of an ordered swimmer suspension. for $ r $ smaller than a threshold $ r _ 1 $, perturbations grow at a rate proportional to their wave number $ q $. beyond $ r _ 1 $, we show that the growth rate is $ \ mathcal { o } ( q ^ 2 ) $ until a second threshold $ r = r _ 2 $ is reached. the suspension is stable for $ r > r _ 2 $. we perform direct numerical simulations to investigate the steady state properties and observe defect turbulence for $ r < r _ 2 $. an investigation of the spatial organisation of defects unravels a hidden transition : for small $ r \ approx 0 $ defects are uniformly distributed and cluster as $ r \ to r _ 1 $. beyond $ r _ 1 $, clustering saturates and defects are arranged in nearly string - like structures.
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arxiv:2305.15197
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transverse momentum spectra of pi ^ { + / - } at midrapidity are measured at high p _ t in p + p and p + pb collisions at 158 gev / nucleon beam energy by the na49 experiment. this study is complementary to our previous results on the same spectra from pb + pb collisions. the nuclear modification factors r _ { a + a / p + p }, r _ { p + a / p + p } and r _ { a + a / p + a } as a function of p _ t are extracted and compared to rhic measurements, thus providing insight into the energy dependence of nuclear modification. the modification factor r _ { a + a / p + a } proved to be consistent with our previous results on the central to peripheral modification factor r _ { cp }. the limitation of our current p _ t range is discussed and planned future upgrades are outlined. some aspects of the fair - cbm experiment are also presented as a natural future continuation of the measurements at very high p _ t.
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arxiv:nucl-ex/0702044
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when an aqueous drop contacts an immiscible oil film, it displays complex interfacial dynamics. upon contact the oil spreads onto the drop ' s liquid - air interface, first forming a curvature that drives an apparent drop spreading motion and later fully engulfing the drop. we study this flow using both 3 - phase lattice - boltzmann simulations based on the conservative phase field model and experiments. inertially and viscously limited dynamics are explored using the ohnesorge number $ oh $ as a function of $ r / h $, the ratio between the initial drop radius $ r $ and the film height $ h $. both regimes show that the apparent spreading radius $ r $ is fairly independent of the film height, and scales with time $ t $ as $ r \ sim t ^ { 1 / 2 } $ for $ oh \ ll 1 $ and for $ oh \ gg 1 $ as $ r \ sim t ^ { 2 / 5 } $. for $ oh \ gg 1 $ we show experimentally that this immiscible apparent spreading motion is analogous with the miscible drop - film coalescence case. contrary to the apparent spreading, however, we find that the late time engulfment dynamics and final interface profiles are significantly affected by the ratio of $ h / r $.
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arxiv:2208.13676
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a new generalized formulation of the spectral condition is proposed for quantum fields with highly singular infrared behavior whose vacuum correlation functions are well defined only under smearing with analytic test functions in momentum space. the euclidean formulation of qft developed by osterwalder and schrader is extended to theories with infrared singular indefinite metric. the corresponding generalization of the reconstruction theorem is obtained. the fulfilment of the generalized spectral condition is verified for quantum fields representable by infinite series in the wick powers of indefinite metric free fields.
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arxiv:math-ph/0205024
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in traditional federated learning approaches like fedavg, the global model underperforms when faced with data heterogeneity. personalized federated learning ( pfl ) enables clients to train personalized models to fit their local data distribution better. however, we surprisingly find that the feature extractor in fedavg is superior to those in most pfl methods. more interestingly, by applying a linear transformation on local features extracted by the feature extractor to align with the classifier, fedavg can surpass the majority of pfl methods. this suggests that the primary cause of fedavg ' s inadequate performance stems from the mismatch between the locally extracted features and the classifier. while current pfl methods mitigate this issue to some extent, their designs compromise the quality of the feature extractor, thus limiting the full potential of pfl. in this paper, we propose a new pfl framework called fedpft to address the mismatch problem while enhancing the quality of the feature extractor. fedpft integrates a feature transformation module, driven by personalized prompts, between the global feature extractor and classifier. in each round, clients first train prompts to transform local features to match the global classifier, followed by training model parameters. this approach can also align the training objectives of clients, reducing the impact of data heterogeneity on model collaboration. moreover, fedpft ' s feature transformation module is highly scalable, allowing for the use of different prompts to tailor local features to various tasks. leveraging this, we introduce a collaborative contrastive learning task to further refine feature extractor quality. our experiments demonstrate that fedpft outperforms state - of - the - art methods by up to 7. 08 %.
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arxiv:2407.16139
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the homotopy type of the complement of a complex coordinate subspace arrangement is studied by fathoming out the connection between its topological and combinatorial structures. a family of arrangements for which the complement is homotopy equivalent to a wedge of spheres is described. one consequence is an application in commutative algebra : certain local rings are proved to be golod, that is, all massey products in their homology vanish.
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arxiv:math/0601279
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the k x - ray spectra of different targets ( cu, zn, and ge ) induced by 3 to 5 mev / u si projectile ions have been measured to determine the k - shell ionization cross - section. a significant difference is observed between the measurements and theoretical estimates, with the latter being about 50 % below the experimental results. this underestimation } is attributed to the charge - exchange from target k - shell to projectile k - and l - shells. such observation can only be possible if the projectile ions attain up to h - and he - like charge states. corresponding projectile charge state fractions have been evaluated from the lorentzian charge state distribution, where mean charge state is taken from the fermi gas model [ phys. rev. lett. 30, 358 ( 1973 ) ] and width from the novikov and teplova approach [ phys. lett. a378, 1286 - 1289 ( 2014 ) ]. the sum of the direct ionization cross - section and k - k + k - l capture cross - sections gives a good agreement with the measured cross - sections. furthermore, we have validated this methodology with available data for si - ion on ti target. such results may be useful in many solid target based applications.
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arxiv:2103.08299
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we study pairs of mutually orthogonal normal matrices with respect to tropical multiplication. minimal orthogonal pairs are characterized. the diameter and girth of three graphs arising from the orthogonality equivalence relation are computed.
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arxiv:2009.13218
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single component nonrelativistic dissipative fluids are treated independently of reference frames and flow - frames. first the basic fields and their balances, then the related thermodynamic relations and the entropy production are calculated and the linear constitutive relations are given. the usual basic fields of mass, momentum, energy and their current densities, the heat flux, pressure tensor and diffusion flux are the time - and spacelike components of the third order mass - momentum - energy density - flux four - tensor. the corresponding galilean transformation rules of the physical quantities are derived. it is proved, that the non - equilibrium thermodynamic frame theory, including the thermostatic gibbs relation and extensivity condition and also the entropy production is independent of the reference frame and also the flow - frame of the fluid. the continuity - fourier - navier - stokes equations are obtained almost in the traditional form if the flow of the fluid is fixed to the temperature. this choice of the flow - frame is the thermo - flow. a simple consequence of the theory is that the relation between the total, kinetic and internal energies is a galilean transformation rule.
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arxiv:1508.00121
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stalactic, taiga, sylvester and baxter monoids arise from the combinatorics of tableaux by identifying words over a fixed ordered alphabet whenever they produce the same tableau via some insertion algorithm. in this paper, three sufficient conditions under which semigroups are finitely based are given. by applying these sufficient conditions, it is shown that all stalactic and taiga monoids of rank greater than or equal to $ 2 $ are finitely based and satisfy the same identities, that all sylvester monoids of rank greater than or equal to $ 2 $ are finitely based and satisfy the same identities and that all baxter monoids of rank greater than or equal to $ 2 $ are finitely based and satisfy the same identities.
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arxiv:2107.00892
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% to 14. 10 %, and chongqing chengan foundation, a state - owned foundation, is the third - largest shareholder, with its ownership stake decreasing from 13. 55 % to 11. 17 %. in august 2024, avatr announced an investment in huawei ' s subsidiary, yinwang ( shenzhen yinwang intelligent technology co., ltd. ), acquiring a 10 % stake for rmb 11. 5 billion and becoming yinwang ' s second - largest shareholder. yinwang, formerly known as huawei intelligent automotive solution, serves as huawei ' s automotive business unit. in the second half of 2023, huawei opted to operate its business unit independently and open it to public equity investment. avatr became the first company to invest in huawei ' s new unit, yinwang. this transition upgraded the previous " hi " ( huawei inside ) model to the enhanced " hi plus " model, allowing huawei to play a more integral role in defining avatr ' s products. in december 2024, avatr has secured over 11 billion yuan ( 1. 5 billion usd ) in its series c financing round. after the capital increase, changan automobile ' s shareholding ratio remained unchanged at 40. 99 %, china southern assets ' shareholding ratio decreased from 7. 81 % to 6. 34 %, anyu fund ' s shareholding ratio was 8. 81 %, and bocom investment ' s shareholding ratio increased from 1. 76 % to 3. 34 %. = = products = = the first avatr vehicle was the large, fully electric suv e11, which stands out from competing designs with a long range on one charge of approximately 700 km ( 430 mi ). the start of production of the first model for the domestic chinese market was scheduled for the second quarter of 2022, with deliveries of the first units scheduled for the end of the same year. finally, the production model called avatr 11, with the letter " e " finally removed from its name, officially debuted in august 2022. sales of the luxury electric car began in november 2022, a year after the official launch of the new company, positioning it as a premium product. at the same time, avatr technology expressed its intention to expand its model offer by 4 new cars by 2025. the first model that is part of the expansion of the avatr brand is an executive car, dubbed the 12, which was officially presented in july 2023. = = = current = = = avatr 11 (
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https://en.wikipedia.org/wiki/Avatr_Technology
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we study the boundary cft under supertranslation in terms of the ads / cft correspondence. in particular, we probe the soft hair btz background by several open string configurations as follows. the ryu - takayanaki formula of holographic entanglement remains intact under supertranslation. the u - shape string probe indicates that the flat part of meson potential is altered by the soft charge. the trailing string solution shows that the hair parameter plays the role of external field in the drag force. the study of hanging string in the brownian motion suggests the transport variables, such as friction coefficient are likely affected by supertranslation.
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arxiv:2206.15262
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the transition between strong and weak allee effects in prey provides a simple regime shift in ecology. a deteriorating environment changes weak allee effects into strong ones. in this paper, we study the interplay between the functional response of holling type iv and both strong and weak allee effects. the model investigated here presents complex dynamics and high codimension bifurcations. in particular, nilpotent cusp bifurcation, nilpotent saddle bifurcation and degenerate hopf bifurcation of codimension 3 are completely analyzed, and the existence of homoclinic and heteroclinic loops are proven. remarkably it is the first time that three limit cycles are discovered in predator - prey models with allee effects. it turns out that strong allee effects destabilize population dynamics, induce more regime shifts, decrease establishment likelihood of both species, increase vulnerability of ecosystem to collapse, while weak allee effects promote sustained oscillations between predators and preys compared to systems without allee effects. the theory developed here provides a sound foundation for understanding predator - prey interactions and biodiversity of species in natural systems.
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arxiv:2007.06806
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we show that there are well separated families of quantum expanders with asymptotically the maximal cardinality allowed by a known upper bound. this has applications to the " growth " of certain operator spaces : it implies asymptotically sharp estimates for the growth of the multiplicity of $ m _ n $ - spaces needed to represent ( up to a constant $ c > 1 $ ) the $ m _ n $ - version of the $ n $ - dimensional operator hilbert space $ oh _ n $ as a direct sum of copies of $ m _ n $. we show that, when $ c $ is close to 1, this multiplicity grows as $ \ exp { \ beta n n ^ 2 } $ for some constant $ \ beta > 0 $. the main idea is to relate quantum expanders with " smooth " points on the matricial analogue of the euclidean unit sphere. this generalizes to operator spaces a classical geometric result on $ n $ - dimensional hilbert space ( corresponding to n = 1 ). in an appendix, we give a quick proof of an inequality ( related to hastings ' s previous work ) on random unitary matrices that is crucial for this paper.
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arxiv:1209.2059
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a phase $ \ delta \ phi $ between amplitudes for $ b ^ 0 \ to k ^ { * 0 } \ pi ^ 0 $ and $ b ^ 0 \ to k ^ { * + } \ pi ^ - $ plays a crucial role in a method for constraining cabibbo - kobayashi - maskawa ( ckm ) parameters. we present a general argument for destructive interference between amplitudes for $ b ^ 0 \ to k ^ { * + } \ pi ^ - $ and $ b ^ 0 \ to k ^ { * 0 } \ pi ^ 0 $ forming together a smaller $ i ( k ^ * \ pi ) = 3 / 2 $ amplitude. applying flavor su ( 3 ) and allowing for conservative theoretical uncertainties, we obtain lower limits on $ | \ delta \ phi | $ and its charge - conjugate. values of these two phases favored by the babar collaboration are in good agreement with our bounds.
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arxiv:1003.5090
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we have computed the number of polarization modes of gravitational waves propagating in the minkowski background in $ f ( r ) $ gravity. this is three of two from transverse - traceless tensor modes and one from a massive trace mode, which confirms the results found in the literature. there is no massless breathing mode and the massive trace mode corresponds to the ricci scalar. a newly defined metric tensor in $ f ( r ) $ gravity satisfies the transverse - traceless ( tt ) condition as well as the tt wave equation.
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arxiv:1608.01764
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accurate galaxy cluster mass measurements from the gravitational lensing of the cosmic microwave background temperature maps depend on mitigating potential biases from the cluster ' s own thermal sunyaev - zel ' dovich ( sz ) effect signal. quadratic lensing estimators use a pair of maps to extract the lensing signal : a large scale gradient map and a small scale lensing map. the sz bias can be eliminated by using an sz - free map in the pair, with the gradient map being favored for signal - to - noise reasons. however, while this approach eliminates the bias, the sz power in small scale lensing map adds extra variance that can become significant for high mass clusters and low noise surveys. in this work, we propose projecting out an sz template to reduce the sz variance. any residual sz signal after template fitting is uncorrelated with the sz - free gradient map, and thus does not bias the mass measurements. for massive clusters above $ 4 \ times 10 ^ { 14 } $ $ m _ { \ odot } $ observed by the upcoming cmb - s4 or simons observatory experiments, we find that the template fitting approach would increase the cluster lensing signal - to - noise by a factor of 1. 4.
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arxiv:1905.07943
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the near - sun kinematics of coronal mass ejections ( cmes ) determine the severity and arrival time of associated geomagnetic storms. we investigate the relationship between the deprojected speed and kinetic energy of cmes and magnetic measures of their solar sources, reconnection flux of associated eruptive events and intrinsic flux rope characteristics. our data covers the period 2010 - 2014 in solar cycle 24. using vector magnetograms of source active regions we estimate the size and nonpotentiality. we compute the total magnetic reconnection flux at the source regions of cmes using the post - eruption arcade method. by forward modeling the cmes we find their deprojected geometric parameters and constrain their kinematics and magnetic properties. based on an analysis of this database we report that the correlation between cme speed and their source active region size and global nonpotentiality is weak, but not negligible. we find the near - sun velocity and kinetic energy of cmes to be well correlated with the associated magnetic reconnection flux. we establish a statistically significant empirical relationship between the cme speed and reconnection flux that may be utilized for prediction purposes. furthermore, we find cme kinematics to be related with the axial magnetic field intensity and relative magnetic helicity of their intrinsic flux ropes. the amount of coronal magnetic helicity shed by cmes is found to be well correlated with their near - sun speeds. the kinetic energy of cmes is well correlated with their intrinsic magnetic energy density. our results constrain processes related to the origin and propagation of cmes and may lead to better empirical forecasting of their arrival and geoeffectiveness.
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arxiv:1808.04144
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in this article, i investigate the use of bayesian updating rules applied to modeling social agents in the case of continuos opinions models. given another agent statement about the continuous value of a variable $ x $, we will see that interesting dynamics emerge when an agent assigns a likelihood to that value that is a mixture of a gaussian and a uniform distribution. this represents the idea the other agent might have no idea about what he is talking about. the effect of updating only the first moments of the distribution will be studied. and we will see that this generates results similar to those of the bounded confidence models. by also updating the second moment, several different opinions always survive in the long run. however, depending on the probability of error and initial uncertainty, those opinions might be clustered around a central value.
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arxiv:0807.4972
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we establish inequalities for assessing the distance between the distribution of a ( possibly multidimensional ) functional of a poisson random measure and that of a gaussian element. our bounds only involve add - one cost operators at the order one - that we evaluate and compare at two different scales - and are specifically tailored for studying the gaussian fluctuations of sequences of geometric functionals displaying a form of weak stabilization - see penrose and yukich ( 2001 ) and penrose ( 2005 ). our main bounds extend the estimates recently exploited by chatterjee and sen ( 2017 ) in the proof of a quantitative version of the central limit theorem ( clt ) for the length of the poisson - based euclidean minimal spanning tree ( mst ). we develop in full detail three applications of our bounds, namely : ( i ) to a quantitative multidimensional spatial clt for functionals of the on - line nearest neighbor graph, ( ii ) to a quantitative multidimensional clt involving functionals of the empirical measure associated with the edge - length of the euclidean mst, and ( iii ) to a collection of multidimensional clts for geometric functionals of the excursion set of heavy - tailed shot noise random fields. application ( i ) is based on a collection of general probabilistic approximations for strongly stabilizing functionals, that is of independent interest.
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arxiv:2010.13362
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we present results from a study of short term variability in 19 archival observations by xmm - newton of 16 ultraluminous x - ray sources ( ulxs ). eight observations ( six sources ) showed intrinsic variability with power spectra in the form of either a power law or broken power law - like continuum and in some cases quasi - periodic oscillations ( qpos ). the remaining observations were used to place upper limits on the strength of possible variability hidden within. seven observations ( seven sources ) yielded upper limits comparable to, or higher than, the values measured from those observations with detectable variations. these represented the seven faintest sources all with f _ x < 3x10 ^ - 12 erg cm ^ - 2 s ^ - 1. in contrast there are four observations ( three sources ) that gave upper limits significantly lower than both the values measured from the ulx observations with detectable variations, and the values expected by comparison with luminous galactic black hole x - ray binaries ( bhbs ) and active galactic nuclei ( agn ) in the observed frequency bandpass ( 10 ^ - 3 - 1 hz ). this is the case irrespective of whether one assumes characteristic frequencies appropriate for a stellar mass ( 10 m _ sun ) or an intermediate mass ( 1000 m _ sun ) black hole, and means that in some ulxs the variability is significantly suppressed compared to bright bhbs and agn. we discuss ways to account for this unusual suppression in terms of both observational and intrinsic effects and whether these solutions are supported by our results.
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arxiv:0905.1265
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in compressed sensing a sparse vector is approximately retrieved from an under - determined equation system $ ax = b $. exact retrieval would mean solving a large combinatorial problem which is well known to be np - hard. for $ b $ of the form $ ax _ 0 + \ epsilon $ where $ x _ 0 $ and $ \ epsilon $ is noise, the ` oracle solution ' is the one you get if you a priori know the support of $ x _ 0 $, and is the best solution one could hope for. we provide a non - convex functional whose global minimum is the oracle solution, with the property that any other local minimizer necessarily has high cardinality. we provide estimates of the type $ \ | \ hat x - x _ 0 \ | _ 2 \ leq c \ | \ epsilon \ | _ 2 $ with constants $ c $ that are significantly lower than for competing methods or theorems, and our theory relies on soft assumptions on the matrix $ a $, in comparison with standard results in the field. the framework also allows to incorporate a priori information on the cardinality of the sought vector. in this case we show that despite being non - convex, our cost functional has no spurious local minima and the global minima is again the ` oracle solution ', thereby providing the first method which is guaranteed to find this point for reasonable levels of noise, without resorting to combinatorial methods.
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arxiv:1806.05283
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in this study, we investigate the performance of few - shot classification models across different domains, specifically natural images and histopathological images. we first train several few - shot classification models on natural images and evaluate their performance on histopathological images. subsequently, we train the same models on histopathological images and compare their performance. we incorporated four histopathology datasets and one natural images dataset and assessed performance across 5 - way 1 - shot, 5 - way 5 - shot, and 5 - way 10 - shot scenarios using a selection of state - of - the - art classification techniques. our experimental results reveal insights into the transferability and generalization capabilities of few - shot classification models between diverse image domains. we analyze the strengths and limitations of these models in adapting to new domains and provide recommendations for optimizing their performance in cross - domain scenarios. this research contributes to advancing our understanding of few - shot learning in the context of image classification across diverse domains.
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arxiv:2410.09176
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we construct some new cohomology theories for topological groups and lie groups and study some of its basic properties. for example, we introduce a cohomology theory based on measurable cochains which are continuous in a neighbourhood of identity. we show that if g and a are locally compact and second countable, then the second cohomology group based on locally continuous measurable cochains as above parametrizes the collection of locally split extensions of g by a.
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arxiv:1009.4519
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the existence of chaotic behavior for the geodesics of the test particles orbiting compact objects is a subject of much current research. some years ago, gu \ ' eron and letelier [ phys. rev. e \ textbf { 66 }, 046611 ( 2002 ) ] reported the existence of chaotic behavior for the geodesics of the test particles orbiting compact objects like black holes induced by specific values of the quadrupolar deformation of the source using as models the erez - - rosen solution and the kerr black hole deformed by an internal multipole term. in this work, we are interesting in the study of the dynamic behavior of geodesics around astrophysical objects with intrinsic quadrupolar deformation or nonisotropic stresses, which induces nonvanishing quadrupolar deformation for the nonrotating limit. for our purpose, we use the tomimatsu - sato spacetime [ phys. rev. lett. \ textbf { 29 } 1344 ( 1972 ) ] and its arbitrary deformed generalization obtained as the particular vacuum case of the five parametric solution of manko et al [ phys. rev. d 62, 044048 ( 2000 ) ], characterizing the geodesic dynamics throughout the poincar \ ' e sections method. in contrast to the results by gu \ ' eron and letelier we find chaotic motion for oblate deformations instead of prolate deformations. it opens the possibility that the particles forming the accretion disk around a large variety of different astrophysical bodies ( nonprolate, e. g., neutron stars ) could exhibit chaotic dynamics. we also conjecture that the existence of an arbitrary deformation parameter is necessary for the existence of chaotic dynamics.
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arxiv:gr-qc/0701065
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we study the higgs - boson decays h0 - > b \ bar { b }, h0 - > \ gamma \ gamma and h0 - > \ gamma z within the framework of the two higgs doublet model ( thdm ) in the context of the decoupling regime, together with tree level unitarity constraints. we show that when the light cp - even higgs boson of the thdm mimics the standard - model higgs boson, not only the one - loop effects to h0 - > { \ gamma \ gamma, \ gamma z } but also the one - loop contribution to h0 - > b \ bar { b } can be used to distinguish between thdm and sm. the size of the quantum effects in h0 - > b \ bar { b } are of the same order as in h0 - > { \ gamma \ gamma, \ gamma z } and can reach 25 % in both cases.
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arxiv:hep-ph/0307391
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communication constraints can significantly impact robots ' ability to share information, coordinate their movements, and synchronize their actions, thus limiting coordination in multi - robot exploration ( mre ) applications. in this work, we address these challenges by modeling the mre application as a dec - pomdp and designing a joint policy that follows a rendezvous plan. this policy allows robots to explore unknown environments while intermittently sharing maps opportunistically or at rendezvous locations without being constrained by joint path optimizations. to generate the rendezvous plan, robots represent the mre task as an instance of the job shop scheduling problem ( jssp ) and minimize jssp metrics. they aim to reduce waiting times and increase connectivity, which correlates to the dec - pomdp rewards and time to complete the task. our simulation results suggest that our method is more efficient than using relays or maintaining intermittent communication with a base station, being a suitable approach for multi - robot exploration. we developed a proof - of - concept using the robot operating system ( ros ) that is available at : https : / / github. com / multirobotplayground / ros - noetic - multi - robot - sandbox.
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arxiv:2309.13494
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we carry out a systematic study of the thermal conductivity of four single - layer transition metal dichalcogenides, mx $ _ 2 $ ( m = mo, w ; x = s, se ) from first - principles by solving the boltzmann transport equation ( bte ). we compare three different theoretical frameworks to solve the bte beyond the relaxation time approximation ( rta ), using the same set of interatomic force constants computed within density functional theory ( dft ), finding that the rta severely underpredicts the thermal conductivity of ms $ _ 2 $ materials. calculations of the different phonon scattering relaxation times of the main collision mechanisms and their corresponding mean free paths ( mfp ) allow evaluating the expected hydrodynamic behaviour in the heat transport of such monolayers. these calculations indicate that despite of their low thermal conductivity, the present tmds can exhibit large hydrodynamic effects, being comparable to those of graphene, especially for wse $ _ 2 $ at high temperatures.
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arxiv:1903.11920
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in this thesis, we investigate various possibilities of weakly interacting massive particle ( wimp ) dark matter ( dm ) and their implications. these possibilities are important because they challenge the viability of wimp dm in light of tight constraints from experiments such as direct detection. we begin by analyzing a fermion dark matter possibility with an axion - like particle ( alp ) portal. we consider theoretical and experimental limits related to neutrino and alp data within a certain mass range, and we find the allowed parameter space. this possibility resolves the problem of the lack of direct detection of wimp dm through the alp portal. furthermore, we examine the limits on photon signals from hess and fermi - lat data. next, we look at a two - component scalar and fermion dark matter possibility, following a similar approach to our previous work. this simple possibility requires only a few additional fields and symmetries to explain neutrino mass and dark matter candidates. by finding parameter space that satisfies various bounds, such as relic density, direct detection, and invisible higgs width, we show that both scalar and fermion particles can serve as dm. this possibility is consistent and offers a rich spectrum of phenomenology that can be tested through collider - based experiments. in our final work, we removie the extra z2 symmetry and added a new pseudoscalar particle in our two compoent model. we test this pseudoscalar particle against multiple dm and non - dm related bounds, including dm lifetime bound, planck bound, direct - detection limits from various target materials, and invisible higgs width. the possibility exhibits a significant parameter space for our pseudoscalar dm while being in agreement with theoretical and experimental limits.
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arxiv:2403.00313
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we obtain a complete classification of all finite - dimensional irreducible modules over classical map superalgebras, provide formulas for their ( super ) characters and a description of their extension groups. furthermore, we describe the block decomposition of the category of finite - dimensional modules for such map superalgebras. as an application, we specialize our results to the case of loop superalgebras in order to obtain a classification of finite - dimensional irreducible modules and block decomposition of the category of finite - dimensional modules over affine lie superalgebras.
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arxiv:2105.06994
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a walk $ w $ in edge - colored graphs is called properly colored ( pc ) if every pair of consecutive edges in $ w $ is of different color. we introduce and study five types of pc acyclicity in edge - colored graphs such that graphs of pc acyclicity of type $ i $ is a proper superset of graphs of acyclicity of type $ i + 1 $, $ i = 1, 2, 3, 4. $ the first three types are equivalent to the absence of pc cycles, pc trails, and pc walks, respectively. while graphs of types 1, 2 and 3 can be recognized in polynomial time, the problem of recognizing graphs of type 4 is, somewhat surprisingly, np - hard even for 2 - edge - colored graphs ( i. e., when only two colors are used ). the same problem with respect to type 5 is polynomial - time solvable for all edge - colored graphs. using the five types, we investigate the border between intractability and tractability for the problems of finding the maximum number of internally vertex disjoint pc paths between two vertices and the minimum number of vertices to meet all pc paths between two vertices.
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arxiv:1601.01824
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positioning has recently received considerable attention as a key enabler in emerging applications such as extended reality, unmanned aerial vehicles and smart environments. these applications require both data communication and high - precision positioning, and thus they are particularly well - suited to be offered in wireless networks ( wns ). the purpose of this paper is to provide a comprehensive overview of existing works and new trends in the field of positioning techniques from both the academic and industrial perspectives. the paper provides a comprehensive overview of positioning in wns, covering the background, applications, measurements, state - of - the - art technologies and future challenges. the paper outlines the applications of positioning from the perspectives of public facilities, enterprises and individual users. we investigate the key performance indicators and measurements of positioning systems, followed by the review of the key enabler techniques such as artificial intelligence / large models and adaptive systems. next, we discuss a number of typical wireless positioning technologies. we extend our overview beyond the academic progress, to include the standardization efforts, and finally, we provide insight into the challenges that remain. the comprehensive overview of exisitng efforts and new trends in the field of positioning from both the academic and industrial communities would be a useful reference to researchers in the field.
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arxiv:2403.11417
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in spectroscopy of charged particles, narrow peaks may appear in initially smooth continuous spectra if magnetic transport of the particles is involved. as such unexpected peaks may be misinterpreted as new physics, their generation is investigated for various experimental configurations.
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arxiv:1508.02880
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a few years ago we predicted theoretically that in systems with nesting of the fermi surface the spin - valley half - metal has lower energy than the spin density wave state. in this paper we suggest a possible way to distinguish these phases experimentally. we calculate dynamical spin susceptibility tensor for both states in the framework of the kubo formalism. discussed phases have different numbers of the bands : four bands in the spin - valley half - metal and only two bands in the spin density wave. therefore, their susceptibilities, as functions of frequency, have different number of peaks. besides, the spin - valley half - metal does not have rotational symmetry, thus, in general the off - diagonal components of susceptibility tensor are non - zero. the spin density wave obeys robust rotational symmetry and off - diagonal components of the susceptibility tensor are zero. these characteristic features can be observed in experiments with inelastic neutron scattering.
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arxiv:2002.05504
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higher - order abstract gsos is a recent extension of turi and plotkin ' s framework of mathematical operational semantics to higher - order languages. the fundamental well - behavedness property of all specifications within the framework is that coalgebraic strong ( bi ) similarity on their operational model is a congruence. in the present work, we establish a corresponding congruence theorem for weak similarity, which is shown to instantiate to well - known concepts such as abramsky ' s applicative similarity for the lambda - calculus. on the way, we develop several techniques of independent interest at the level of abstract categories, including relation liftings of mixed - variance bifunctors and higher - order gsos laws, as well as howe ' s method.
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arxiv:2302.08200
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kernel methods play a critical role in many machine learning algorithms. they are useful in manifold learning, classification, clustering and other data analysis tasks. setting the kernel ' s scale parameter, also referred to as the kernel ' s bandwidth, highly affects the performance of the task in hand. we propose to set a scale parameter that is tailored to one of two types of tasks : classification and manifold learning. for manifold learning, we seek a scale which is best at capturing the manifold ' s intrinsic dimension. for classification, we propose three methods for estimating the scale, which optimize the classification results in different senses. the proposed frameworks are simulated on artificial and on real datasets. the results show a high correlation between optimal classification rates and the estimated scales. finally, we demonstrate the approach on a seismic event classification task.
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arxiv:1707.01093
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we give a short survey of the rationality problem for quasi - monomial actions which includes noether ' s problem and the rationality problem for algebraic tori, and report some results on rationality problem in three recent papers hoshi, kang and kitayama [ hkki ], hoshi, kang and kunyavskii [ hkku ] and hoshi and yamasaki [ hy ].
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arxiv:1411.2790
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model spectra of neutron star atmospheres are nowadays widely used to fit the observed thermal x - ray spectra of neutron stars. this fitting is the key element in the method of the neutronstar radius determination. here, we present the basic assumptions used for the neutron star atmosphere modeling as well as the main qualitative features of the stellar atmospheres leading to the deviations of the emergent model spectrum from blackbody. we describe the properties of two of our model atmosphere grids : ( i ) pure carbon atmospheres for relatively cool neutron stars ( 1 - - 4 mk ) and ( ii ) hot atmospheres with compton scattering taken into account. the results obtained by applying these grids to model the x - ray spectra of the central compact object in supernova remnant hess 1731 - 347, and two x - ray bursting neutron stars in low - mass x - ray binaries, 4u 1724 - 307 and 4u 1608 - 52, are presented. possible systematic uncertainties associated with the obtained neutron star radii are discussed.
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arxiv:1510.06962
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we give the infinite - dimensional representation for the elliptic $ k $ - operator satisfying the boundary yang - baxter equation. by restricting the functional space to finite - dimensional space, we construct the elliptic $ k $ - matrix associated to belavin ' s completely $ \ mathbb { z } $ - symmetric $ r $ - matrix.
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arxiv:hep-th/9507123
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plasma in low earth orbit can damage electronic components and potentially jeopardise the scientific missions in space. predicting the accumulated damage and understanding the components ' radiation tolerance are important to mission planning. in this manuscript we report on the observed radiation tolerance of single photon detectors and a liquid crystal polarization rotator. we conclude that an uncooled si apd could continue to operate from more than a month up to beyond the lifetime of the satellite depending on the orbit. the polarization rotator was also unaffected by the exposed dosage.
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arxiv:1501.03595
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topological materials can host edge and corner states that are protected from disorder and material imperfections. in particular, the topological edge states of mechanical structures present unmatched opportunities for achieving robust responses in wave guiding, sensing, computation, and filtering. however, determining whether a mechanical structure is topologically nontrivial and features topologically - protected modes has hitherto relied on theoretical models. this strong requirement has limited the experimental and practical significance of topological mechanics to laboratory demonstrations. here, we introduce and validate an experimental method to detect the topologically protected zero modes of mechanical structures without resorting to any modeling step. our practical method is based on a simple electrostatic analogy : topological zero modes are akin to electric charges. to detect them, we identify elementary mechanical molecules and measure their chiral polarization, a recently introduced marker of topology in chiral phases. topological zero modes are then identified as singularities of the polarization field. our method readily applies to any mechanical structure and effectively detects the edge and corner states of regular and higher - order topological insulators. our findings extend the reach of chiral topological phases beyond designer materials, and allow their direct experimental investigation.
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arxiv:2304.04832
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a theoretical study was conducted of the size dependence of the blocking temperature of a system of interacting core / shell nanoparticles. a method for estimating the blocking temperature of interacting core / shell nanoparticles is presented, which allows to be calculated more correctly than using the neel relation. it was shown that together with an increase in the intensity of the magnetostatic interaction ( concentration of nanoparticles ) the blocking temperature increases, while the growth of the external magnetic field leads to the opposite effect. moreover, the of large nanoparticles changes more significantly. a comparison of different methods for determining the blocking temperature from the zfc and fc curves showed that the method for determining using the temperature derivative of the difference between zfc and fc is more preferable.
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arxiv:2003.05612
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= a ) { \ displaystyle \ forall a ( a = a ) } substitution property : sometimes referred to as leibniz ' s law, generally states that if two things are equal, then any property of one must be a property of the other. it can be stated formally as : for every a and b, and any formula ( x ), { \ displaystyle \ phi ( x ), } ( with a free variable x ), if a = b, { \ displaystyle a = b, } then ( a ) { \ displaystyle \ phi ( a ) } implies ( b ). { \ displaystyle \ phi ( b ). } stated symbolically as : ( a = b ) [ ( a ) ⇒ ( b ) ] { \ displaystyle ( a = b ) \ implies { \ bigl [ } \ phi ( a ) \ rightarrow \ phi ( b ) { \ bigr ] } } function application is also sometimes included in the axioms of equality, but isn ' t necessary as it can be deduced from the other two axioms, and similarly for symmetry and transitivity. ( see § derivations of basic properties ) in first - order logic, these are axiom schemas ( usually, see below ), each of which specify an infinite set of axioms. if a theory has a predicate that satisfies the law of identity and substitution property, it is common to say that it " has equality ", or is " a theory with equality ". the use of " equality " here somewhat of a misnomer in that any system with equality can be modeled by a theory without standard identity, and with indiscernibles. those two axioms are strong enough, however, to be isomorphic to a model with idenitity ; that is, if a system has a predicate staisfying those axioms without standard equality, there is a model of that system with standard equality. this can be done by defining a new domain whose objects are the equivalence classes of the original " equality ". if the relation is interpreted as equality, then those properties are enough, since if x { \ displaystyle x } has all the same properties as y, { \ displaystyle y, } and x { \ displaystyle x } has the property of being equal to x, { \ displaystyle x, } then y { \ displaystyle y } has the property of being equal to x. { \
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https://en.wikipedia.org/wiki/Equality_(mathematics)
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we show why the threshold for primordial black hole formation is universal ( independent from the shape of the perturbation ) when expressed in terms of the volume averaged compaction function. the proof is rooted in the self - similarity of the gravitational collapse phenomenon at criticality.
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arxiv:2405.05208
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, arrange and promote music on her own rock and roll music label was cordell jackson ( 1923 – 2004 ). trina shoemaker is a mixer, record producer and sound engineer who became the first woman to win the grammy award for best engineered album in 1998 for her work on the globe sessions. gail davies was the first female producer in country music, delivering a string of top 10 hits in the 1970s and 1980s including " someone is looking for someone like you ", " blue heartache " and " i ' ll be there ( if you ever want me ) ". when she moved to nashville in 1976, men " didn ' t want to work for a woman " and she was told women in the city were " still barefoot, pregnant and [ singing ] in the vocal booth. " when jonell polansky arrived in nashville in 1994, with a degree in electrical engineering and recording experience in the bay area, she was told " you ' re a woman, and we already had one " — a reference to wendy waldman. kk proffitt, a studio " owner and chief engineer ", states that men in nashville do not want to have women in the recording booth. at a meeting of the audio engineering society, proffitt was told to " shut up " by a male producer when she raised the issue of updating studio recording technologies. proffitt said she " finds sexism rampant in the industry ". other notable women include : sylvia robinson, early hip hop music producer susan rogers, engineer for purple rain genya ravan, producer the dead boys ' young, loud and snotty ; delia derbyshire, british electronics pioneer lari white, a co - producer on toby keith ' s white trash with money leslie ann jones, recording engineer sylvia massy, engineer and producer for tool, system of a down, and johnny cash ethel gabriel, producer and record executive rca victor = = = sub - disciplines = = = there are four distinct steps to the commercial production of a recording : recording, editing, mixing, and mastering. typically, each is performed by a sound engineer who specializes only in that part of the production. studio engineer – an engineer working within a studio facility, either with a producer or independently. recording engineer – the engineer who records sound. assistant engineer – often employed in larger studios, allowing them to train to become full - time engineers. they often assist full - time engineers with microphone setups, session breakdowns and in some cases, rough mixes. mixing engineer – a person who creates
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https://en.wikipedia.org/wiki/Audio_engineer
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we present initial limit datalog, a new extensible class of constrained horn clauses for which the satisfiability problem is decidable. the class may be viewed as a generalisation to higher - order logic ( with a simple restriction on types ) of the first - order language limit datalog $ _ z $ ( a fragment of datalog modulo linear integer arithmetic ), but can be instantiated with any suitable background theory. for example, the fragment is decidable over any countable well - quasi - order with a decidable first - order theory, such as natural number vectors under componentwise linear arithmetic, and words of a bounded, context - free language ordered by the subword relation. formulas of initial limit datalog have the property that, under some assumptions on the background theory, their satisfiability can be witnessed by a new kind of term model which we call entwined structures. whilst the set of all models is typically uncountable, the set of all entwined structures is recursively enumerable, and model checking is decidable.
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arxiv:2104.14175
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motivation : a major challenge in the development of machine learning based methods in computational biology is that data may not be accurately labeled due to the time and resources required for experimentally annotating properties of proteins and dna sequences. standard supervised learning algorithms assume accurate instance - level labeling of training data. multiple instance learning is a paradigm for handling such labeling ambiguities. however, the widely used large - margin classification methods for multiple instance learning are heuristic in nature with high computational requirements. in this paper, we present stochastic sub - gradient optimization large margin algorithms for multiple instance classification and ranking, and provide them in a software suite called pylemmings. results : we have tested pylemmings on a number of bioinformatics problems as well as benchmark datasets. pylemmings has successfully been able to identify functionally important segments of proteins : binding sites in calmodulin binding proteins, prion forming regions, and amyloid cores. pylemmings achieves state - of - the - art performance in all these tasks, demonstrating the value of multiple instance learning. furthermore, our method has shown more than 100 - fold improvement in terms of running time as compared to heuristic solutions with improved accuracy over benchmark datasets. availability and implementation : pylemmings python package is available for download at : http : / / faculty. pieas. edu. pk / fayyaz / software. html # pylemmings.
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arxiv:1711.04913
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a theoretical investigation has been carried out to examine the ion - acoustic shock waves ( iashws ) in a magnetized degenerate quantum plasma system containing inertialess ultra - relativistically degenerate electrons, and inertial non - relativistic positively charged heavy and light ions. the burgers ' equation is derived by employing reductive perturbation method. it can be seen that under consideration of non - relativistic positively charged heavy and light ions, the plasma model supports only positive electrostatic shock structure. it is also observed that the charge state and number density of the non - relativistic heavy and light ions enhance the amplitude of iashws, and the steepness of the shock profile is decreased with ion kinematic viscosity ( $ \ eta $ ). the findings of our present investigation will be helpful in understanding the nonlinear propagation of iashws in white dwarfs and neutron stars.
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arxiv:2103.15863
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the axion monodromy model involves a canonical scalar field that is governed by a linear potential with superimposed modulations. the modulations in the potential are responsible for a resonant behavior which gives rise to persisting oscillations in the scalar and, to a smaller extent, in the tensor power spectra. interestingly, such spectra have been shown to lead to an improved fit to the cosmological data than the more conventional, nearly scale invariant, primordial power spectra. the scalar bi - spectrum in the model too exhibits continued modulations and the resonance is known to boost the amplitude of the scalar non - gaussianity parameter to rather large values. an analytical expression for the scalar bi - spectrum had been arrived at earlier which, in fact, has been used to compare the model with the cosmic microwave background anisotropies at the level of three - point functions involving scalars. in this work, with future applications in mind, we arrive at a similar analytical template for the scalar - scalar - tensor cross - correlation. we also analytically establish the consistency relation ( in the squeezed limit ) for this three - point function. we conclude with a summary of the main results obtained.
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arxiv:1605.05292
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people express their opinions and emotions freely in social media posts and online reviews that contain valuable feedback for multiple stakeholders such as businesses and political campaigns. manually extracting opinions and emotions from large volumes of such posts is an impossible task. therefore, automated processing of these posts to extract opinions and emotions is an important research problem. however, human emotion detection is a challenging task due to the complexity and nuanced nature. to overcome these barriers, researchers have extensively used techniques such as deep learning, distant supervision, and transfer learning. in this paper, we propose a novel pyramid attention network ( pan ) based model for emotion detection in microblogs. the main advantage of our approach is that pan has the capability to evaluate sentences in different perspectives to capture multiple emotions existing in a single text. the proposed model was evaluated on a recently released dataset and the results achieved the state - of - the - art accuracy of 58. 9 %.
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arxiv:1907.07653
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the higher order kirchhoff type equation $ $ \ int _ { \ mathbb { r } ^ { 2m } } ( | \ nabla ^ m u | ^ 2 + \ sum _ { \ gamma = 0 } ^ { m - 1 } a _ { \ gamma } ( x ) | \ nabla ^ { \ gamma } u | ^ 2 ) dx \ left ( ( - \ delta ) ^ m u + \ sum _ { \ gamma = 0 } ^ { m - 1 } ( - 1 ) ^ \ gamma \ nabla ^ \ gamma \ cdot ( a _ \ gamma ( x ) \ nabla ^ \ gamma u ) \ right ) = \ frac { f ( x, u ) } { | x | ^ \ beta } + \ epsilon h ( x ) \ \ \ text { in } \ \ \ mathbb { r } ^ { 2m } $ $ is considered in this paper. we assume that the nonlinearity of the equation has exponential critical growth and prove that, for a positive $ \ epsilon $ which is small enough, there are two distinct nontrivial solutions to the equation. when $ \ epsilon = 0 $, we also prove that the equation has a nontrivial mountain - pass type solution.
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arxiv:1507.05280
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recent lhc results concerning full jet - quenching in pbpb collisions have been presented in terms of a jet asymmetry parameter, measuring the imbalance between the transverse momenta of leading and subleading jets. we examine the potential sensitivity of this distribution to fluctuations from the heavy - ion background. our results suggest that a detailed estimate of the true fluctuations would be of benefit in extracting quantitative information about jet quenching. we also find that the apparent impact of fluctuations on the jet asymmetry distribution can depend significantly on the choice of low - pt threshold used for the simulation of the hard pp events.
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arxiv:1101.2878
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in a recent paper [ j. - c. pain, opt. spectrosc. $ { \ bf 218 } $, 1105 - 1109 ( 2020 ) ], we discussed the link between expectation values of powers of $ r $ and clebsch - gordan coefficients. in this short note we provide additional information, reminding that such a connection is a direct consequence of group theory. the hydrogenic radial wavefunctions form bases for infinite dimensional representations of the algebra of the non - compact group $ o ( 2, 1 ) $ and the expectation values $ r ^ p $ and $ r ^ { - p } $ ( $ p $ being positive ) transform as tensors with respect to this algebra. as shown a long time ago by armstrong [ l. armstrong jr., j. phys. ( paris ) suppl. c 4 $ { \ bf 31 } $, 17 ( 1970 ) ], analysis of matrix elements of $ r ^ p $ and $ r ^ { - p } $ reveals that the wigner - eckart theorem is valid for this group and that the corresponding clebsch - gordan coefficients are proportional to the usual $ so ( 3 ) $ clebsch - gordan coefficients. this proportionality provides simple explanations of the selection rules for hydrogenic radial matrix elements pointed out by pasternack and sternheimer, and the proportionality of hydrogenic expectation values of $ r ^ p $ and $ r ^ { - p } $ to $ 3jm $ symbols.
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arxiv:2101.07872
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convective core overshooting has a strong influence on the evolution of stars of moderate and high mass. studies of double - lined eclipsing binaries and stellar oscillations have renewed interest in the possible dependence of overshooting on stellar mass, which has been poorly constrained by observations so far. here we have used a sample of 29 well - studied double - lined eclipsing binaries in key locations of the h - r diagram to establish the explicit dependence of f ( ov ) on mass, where f ( ov ) is the free parameter in the diffusive approximation to overshooting. measurements of the masses, radii, and temperatures of the binary components were compared against stellar evolution calculations based on the mesa code to infer semi - empirical values of f ( ov ) for each component. we find a clear mass dependence such that f ( ov ) rises sharply from zero in the range 1. 2 - - 2. 0 solar masses, and levels off thereafter up to the 4. 4 solar mass limit of our sample. tests with two different element mixtures indicate the trend is the same, and we find it is also qualitatively similar to the one established in our previous study with the classical step - function implementation of overshooting characterized by the free parameter alpha ( ov ). based on these measurements we infer an approximate relationship between the two overshooting parameters of alpha ( ov ) / f ( ov ) = 11. 36 + / - 0. 22, with a possible dependence on stellar properties.
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arxiv:1710.08417
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we discuss characteristic features of su ( 3 ) partial dynamical symmetry in relation to nuclear spectroscopy and compare with previous broken - su ( 3 ) calculations for ^ { 168 } er.
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arxiv:nucl-th/9911028
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experimental results concerning the dynamical fission of quasiprojectiles in semiperipheral collisions for the system 80 kr + 48 ca at 35 mev / nucleon are presented. data have been collected with four blocks of the fazia setup in the first physics experiment of the fazia collaboration. the degree of isospin equilibration between the two fission fragments and its dependence on their charge asymmetry is investigated. the data are compared with the results of the amd model coupled to gemini as an afterburner, in order to get hints about the timescale of the process.
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arxiv:2010.00447
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we show that the spin liquid phase of the half - filled hubbard model on the triangular lattice can be described by a pure spin model. this is based on a high - order strong coupling expansion ( up to order 12 ) using perturbative continuous unitary transformations. the resulting spin model is consistent with a transition from three - sublattice long - range magnetic order to an insulating spin liquid phase, and with a jump of the double occupancy at the transition. exact diagonalizations of both models show that the effective spin model is quantitatively accurate well into the spin liquid phase, and a comparison with the gutzwiller projected fermi sea suggests a gapless spectrum and a spinon fermi surface.
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arxiv:1006.5649
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the multifractal ( mf ) distribution of the electrostatic potential near any conformally invariant fractal boundary, like a critical o ( n ) loop or a $ q $ - state potts cluster, is solved in two dimensions. the dimension $ \ hat f ( \ theta ) $ of the boundary set with local wedge angle $ \ theta $ is $ \ hat f ( \ theta ) = \ frac { \ pi } { \ theta } - \ frac { 25 - c } { 12 } \ frac { ( \ pi - \ theta ) ^ 2 } { \ theta ( 2 \ pi - \ theta ) } $, with $ c $ the central charge of the model. as a corollary, the dimensions $ d _ { \ rm ep } = sup _ { \ theta } \ hat f ( \ theta ) $ of the external perimeter and $ d _ { \ rm h } $ of the hull of a potts cluster obey the duality equation $ ( d _ { \ rm ep } - 1 ) ( d _ { \ rm h } - 1 ) = { 1 / 4 } $. a related covariant mf spectrum is obtained for self - avoiding walks anchored at cluster boundaries.
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arxiv:cond-mat/9908314
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we report magneto - transport measurements on a superconducting molybdenum - germanium ( moge ) film of thickness $ d $ = 50 nm in parallel magnetic fields and show evidence of a transition from a meissner state to a resistive state of spontaneous perpendicular vortices generated by thermal fluctuations above a certain temperature $ t > t _ v ( b ) $. here $ t _ v $ appears to match the vortex core explosion condition $ d \ approx 4. 4 \ xi ( t _ v ) $, where $ \ xi $ is the coherence length. for $ t > t _ v $, we observed that a nonlinear current - voltage ( $ iv $ ) response ( ohmic at low currents and the power law $ v \ propto i ^ \ beta $ at higher $ i $ ) is exponentially dependent on $ b ^ 2 $. we propose a model in which the resistive state at $ t > t _ v $ is due to thermally - activated hopping of spontaneous perpendicular vortices tuned by the pairbreaking effect of the parallel $ b $. keywords : vortex, vortices, fluxon, flux lattice, mixed state, lower critical field
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arxiv:1510.03259
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the effect of a magnetic field on mott - hubbard systems is investigated by studying the half - filled hubbard model in the limit of infinite dimensions. a first - order metamagnetic transition between the strongly correlated metal and the mott insulator is found for a critical value of the applied field. the field and temperature dependence of the magnetization, one - particle properties and susceptibility are studied and compared to the gutzwiller approximation. the experimental relevance for transition - metal oxides and liquid $ ^ { 3 } he $ is discussed.
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arxiv:cond-mat/9403016
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this paper presents ` ` stim ", a fast simulator for quantum stabilizer circuits. the paper explains how stim works and compares it to existing tools. with no foreknowledge, stim can analyze a distance 100 surface code circuit ( 20 thousand qubits, 8 million gates, 1 million measurements ) in 15 seconds and then begin sampling full circuit shots at a rate of 1 khz. stim uses a stabilizer tableau representation, similar to aaronson and gottesman ' s chp simulator, but with three main improvements. first, stim improves the asymptotic complexity of deterministic measurement from quadratic to linear by tracking the { \ em inverse } of the circuit ' s stabilizer tableau. second, stim improves the constant factors of the algorithm by using a cache - friendly data layout and 256 bit wide simd instructions. third, stim only uses expensive stabilizer tableau simulation to create an initial reference sample. further samples are collected in bulk by using that sample as a reference for batches of pauli frames propagating through the circuit.
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arxiv:2103.02202
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great achievements have been made in alloying of two - dimensional ( 2d ) semiconducting transition metal dichalcogenides ( tmds ), which can allow tunable band gaps for practical applications in optoelectronic devices. however, telluride - based tmds alloys were less studied due to the difficulties of sample synthesis. here, in this work we report the large - area synthesis of 2d motexse2 - x alloy films with controllable te composition by a modified alkali metal halides assisted chemical vapor deposition method. the as - prepared films have millimeter - scale transverse size. raman spectra experiments combining calculated raman spectra and vibrational images obtained by density functional theory ( dft ) confirmed the 2h - phase of the motexse2 - x alloys. the a1g mode of mose2 shows a significant downshift accompanied by asymmetric broadening to lower wavenumber with increasing value of x, while e12g mode seems unchanged, which were well explained by a phonon confinement model. our work provides a simple method to synthesize large - scale 2h phase te - based 2d tmds alloys for their further applications.
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arxiv:1904.10218
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there has been much recent interest in the satisfiability of random boolean formulas. a random k - sat formula is the conjunction of m random clauses, each of which is the disjunction of k literals ( a variable or its negation ). it is known that when the number of variables n is large, there is a sharp transition from satisfiability to unsatisfiability ; in the case of 2 - sat this happens when m / n - - > 1, for 3 - sat the critical ratio is thought to be m / n ~ 4. 2. the sharpness of this transition is characterized by a critical exponent, sometimes called \ nu = \ nu _ k ( the smaller the value of \ nu the sharper the transition ). experiments have suggested that \ nu _ 3 = 1. 5 + - 0. 1, \ nu _ 4 = 1. 25 + - 0. 05, \ nu _ 5 = 1. 1 + - 0. 05, \ nu _ 6 = 1. 05 + - 0. 05, and heuristics have suggested that \ nu _ k - - > 1 as k - - > infinity. we give here a simple proof that each of these exponents is at least 2 ( provided the exponent is well - defined ). this result holds for each of the three standard ensembles of random k - sat formulas : m clauses selected uniformly at random without replacement, m clauses selected uniformly at random with replacement, and each clause selected with probability p independent of the other clauses. we also obtain similar results for q - colorability and the appearance of a q - core in a random graph.
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arxiv:math/0005136
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the data release dr2 of gaia mission was of great help in precise determination of fundamental parameters of close visual binary and multiple systems ( cvbmss ), especially masses of their components, which are crucial parameters in understating formation and and evolution of stars and galaxies. this article presents the complete set of fundamental parameters of two nearby ( cvbss ), these are hip 19206 and hip 84425. we used a combination of two methods ; the first one is tokovinin ' s dynamical method to solve the orbit of the system and to estimate orbital elements and the dynamical mass sum, and the second one is al - wardat ' s method for analyzing cvbmss to estimate the physical parameters of the individual components. the latest method employs grids of kurucz line - blanketed plane parallel model atmospheres to build synthetic spectral energy distributions ( sed ) of the individual components. trigonometric parallax measurements given by gaia dr2 and hipparcos catalogues are used to analyse the two systems. the difference in these measurements yielded slight discrepancies in the fundamental parameters of the individual components especially masses. so, a new dynamical parallax is suggested in this work based on the most convenient mass sum as given by each of the two methods. the new dynamical parallax for the system hip 19205 as $ 22. 97 \ pm 0. 95 $ mas coincides well with the trigonometric one given recently ( in december 2020 ) by gaia dr3 as $ 22. 3689 \ pm 0. 4056 $ mas. the positions of the components of the two systems on the evolutionary tracks and isochrones are plotted, which suggest that all components are solar - type main sequence stars. their most probable formation and evolution scenarios are also discussed.
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arxiv:2111.11675
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human action recognition in videos is a critical task with significant implications for numerous applications, including surveillance, sports analytics, and healthcare. the challenge lies in creating models that are both precise in their recognition capabilities and efficient enough for practical use. this study conducts an in - depth analysis of various deep learning models to address this challenge. utilizing a subset of the ucf101 videos dataset, we focus on convolutional neural networks ( cnns ), recurrent neural networks ( rnns ), and two - stream convnets. the research reveals that while cnns effectively capture spatial features and rnns encode temporal sequences, two - stream convnets exhibit superior performance by integrating spatial and temporal dimensions. these insights are distilled from the evaluation metrics of accuracy, precision, recall, and f1 - score. the results of this study underscore the potential of composite models in achieving robust human action recognition and suggest avenues for future research in optimizing these models for real - world deployment.
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arxiv:2403.06810
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we extend loeper ' s $ l ^ 2 $ - estimate relating the electric fields to the densities for the vlasov - poisson system to $ l ^ p $, with $ 1 < p < + \ infty $, based on the helmholtz - weyl decomposition. this allows us to generalize both the classical loeper ' s $ 2 $ - wasserstein stability estimate and the recent stability estimate by the first author relying on the newly introduced kinetic wasserstein distance to kinetic wasserstein distances of order $ 1 < p < + \ infty $.
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arxiv:2212.09293
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we analyse the functional derivative of the cosmic - shear power spectrum $ c _ \ ell ^ \ gamma $ with respect to the cosmic expansion function. our interest in doing so is two - fold : ( i ) in view of attempts to detect minor changes of the cosmic expansion function which may be due to a possibly time - dependent dark - energy density, we wish to know how sensitive the weak - lensing power spectrum is to changes in the expansion function. ( ii ) in view of recent empirical determinations of the cosmic expansion function from distance measurements, independent of specific cosmological models, we wish to find out how uncertainties in the expansion function translate to uncertainties in the cosmic - shear power spectrum. we find the following answers : relative changes of the expansion function are amplified by the cosmic - shear power spectrum by a factor $ \ approx 2 - 6 $, weakly depending on the scale factor where the change is applied, and the current uncertainty of one example for an empirically determined expansion function translates to a relative uncertainty of the cosmic - shear power spectrum of $ \ approx10 \, \ % $.
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arxiv:2011.03202
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ideal fluid dynamics is studied as a relativistic field theory with particular importance on its hamiltonian structure. the schwinger condition, whose integrated version yields the stress tensor conservation, is explicitly verified both in equal - time and light - cone coordinate systems. we also consider the hamiltonian formulation of fluids interacting with an external gauge field. the complementary roles of the canonical ( noether ) stress tensor and the symmetric one obtained by metric variation are discussed. finally, a non - relativistic reduction of the system in light - cone coordinates has been carried out which reproduces results found earlier in the literature.
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arxiv:1409.7175
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the inner 10 pc of our galaxy contains many counterpart candidates of the very high energy ( vhe ; > 100 gev ) gamma - ray point source hess j1745 - 290. within the point spread function of the h. e. s. s. measurement, at least three objects are capable of accelerating particles to very high energies and beyond, and of providing the observed gamma - ray flux. previous attempts to address this source confusion were hampered by the fact that the projected distances between those objects were of the order of the error circle radius of the emission centroid ( 34 ", dominated by the pointing uncertainty of the h. e. s. s. instrument ). here we present h. e. s. s. data of the galactic centre region, recorded with an improved control of the instrument pointing compared to h. e. s. s. standard pointing procedures. stars observed during gamma - ray observations by optical guiding cameras mounted on each h. e. s. s. telescope are used for off - line pointing calibration, thereby decreasing the systematic pointing uncertainties from 20 " to 6 " per axis. the position of hess j1745 - 290 is obtained by fitting a multi - gaussian profile to the background - subtracted gamma - ray count map. a spatial comparison of the best - fit position of hess j1745 - 290 with the position and morphology of candidate counterparts is performed. the position is, within a total error circle radius of 13 ", coincident with the position of the supermassive black hole sgr a * and the recently discovered pulsar wind nebula candidate g359. 95 - 0. 04. it is significantly displaced from the centroid of the supernova remnant sgr a east, excluding this object with high probability as the dominant source of the vhe gamma - ray emission.
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arxiv:0911.1912
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in this paper, we generalizing the main result in liu [ 10 ] to weak hopf coquasigroups case. we first define and study group - cograded weak hopf quasigroups, which generalize both group - cograded hopf quasigroups and weak hopf group - coalgebras. then we introduce the notion of p - yetter - drinfeld weak quasimodule over group - cograded weak hopf quasigroups h. if the antipode of h is bijective, we show that the category ydwq ( h ) of yetter - drinfeld weak quasimodules over h is a crossed category, and the subcategory yd ( h ) of yetter - drinfeld modules is a braided crossed category.
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arxiv:2212.00363
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we study the dynamic wetting of a self - propelled viscous droplet using the time - dependent lubrication equation on a conical - shaped substrate for different cone radii, cone angles and slip lengths. the droplet velocity is found to increase with the cone angle and the slip length, but decrease with the cone radius. we show that a film is formed at the receding part of the droplet, much like the classical landau - levich - derjaguin ( lld ) film. the film thickness $ h _ f $ is found to decrease with the slip length $ \ lambda $. by using the approach of matching asymptotic profiles in the film region and the quasi - static droplet, we obtain the same film thickness as the results from the lubrication approach for all slip lengths. we identify two scaling laws for the asymptotic regimes : $ h _ fh ' ' _ o \ sim ca ^ { 2 / 3 } $ for $ \ lambda \ ll h _ f $ and $ h _ f h ' ' ^ { 3 } _ o \ sim ( ca / \ lambda ) ^ 2 $ for $ \ lambda \ gg h _ f $, here $ 1 / h ' ' _ o $ is a characteristic length at the receding contact line and $ ca $ is the capillary number. we compare the position and the shape of the droplet predicted from our continuum theory with molecular dynamics simulations, which are in close agreement. our results show that manipulating the droplet size, the cone angle and the slip length provides different schemes for guiding droplet motion and coating the substrate with a film.
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arxiv:2008.03058
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in this essay i will give a strictly subjective selection of different types of zeta functions. instead of providing a complete list, i will rather try to give the central concepts and ideas underlying the theory. this article is going to appear in the collected works of erich k \ " ahler.
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arxiv:math/0210060
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we studied the spherical collapse model in the flat $ \ lambda $ cdm cosmology and provided exact and analytical formulaes for the calculation of the two important parameters in the application of press - schechter theory, the critical density contrast and the ratio of cluster / background densities at the virialization point in terms of a media variable which can be solved precisely by numerical methods.
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arxiv:astro-ph/0412628
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we present a theoretical prediction for the photon spectrum in radiative upsilon decay. parts of the spectrum have already been understood, but an understanding of the endpoint region has remained elusive. in this paper we provide the missing piece, and resolve a controversy in the literature. we treat the endpoint region of upsilon - > x gamma decay within the framework of the soft - collinear effective theory ( scet ). within this approach the upsilon structure function arises naturally, and kinematic logarithms are summed by running operators using renormalization group equations. in a previous paper we studied the color - octet contribution to the decay. here we treat the color - singlet contribution. we combine our result with previous results to obtain the upsilon - > x gamma spectrum. we find that resumming the color - singlet contribution in the endpoint gives a result that is in much better agreement with the data than the leading order prediction.
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arxiv:hep-ph/0212094
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image forensics research has recently witnessed a lot of advancements towards developing computational models capable of accurately detecting natural images captured by cameras and gan generated images. however, it is also important to ensure whether these computational models are fair enough and do not produce biased outcomes that could eventually harm certain societal groups or cause serious security threats. exploring fairness in image forensic algorithms is an initial step towards mitigating these biases. this study explores bias in visual transformer based image forensic algorithms that classify natural and gan images, since visual transformers are recently being widely used in image classification based tasks, including in the area of image forensics. the proposed study procures bias evaluation corpora to analyze bias in gender, racial, affective, and intersectional domains using a wide set of individual and pairwise bias evaluation measures. since the robustness of the algorithms against image compression is an important factor to be considered in forensic tasks, this study also analyzes the impact of image compression on model bias. hence to study the impact of image compression on model bias, a two - phase evaluation setting is followed, where the experiments are carried out in uncompressed and compressed evaluation settings. the study could identify bias existences in the visual transformer based models distinguishing natural and gan images, and also observes that image compression impacts model biases, predominantly amplifying the presence of biases in class gan predictions.
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arxiv:2310.12076
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low - light conditions have an adverse impact on machine cognition, limiting the performance of computer vision systems in real life. since low - light data is limited and difficult to annotate, we focus on image processing to enhance low - light images and improve the performance of any downstream task model, instead of fine - tuning each of the models which can be prohibitively expensive. we propose to improve the existing zero - reference low - light enhancement by leveraging the clip model to capture image prior and for semantic guidance. specifically, we propose a data augmentation strategy to learn an image prior via prompt learning, based on image sampling, to learn the image prior without any need for paired or unpaired normal - light data. next, we propose a semantic guidance strategy that maximally takes advantage of existing low - light annotation by introducing both content and context cues about the image training patches. we experimentally show, in a qualitative study, that the proposed prior and semantic guidance help to improve the overall image contrast and hue, as well as improve background - foreground discrimination, resulting in reduced over - saturation and noise over - amplification, common in related zero - reference methods. as we target machine cognition, rather than rely on assuming the correlation between human perception and downstream task performance, we conduct and present an ablation study and comparison with related zero - reference methods in terms of task - based performance across many low - light datasets, including image classification, object and face detection, showing the effectiveness of our proposed method.
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arxiv:2412.07693
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in order to solve the fluid - structure interaction problem of newtonian fluid, a fluid - structure interaction approach is proposed based on non - ordinary state - based peridynamics ( nosb - pd ) and updated lagrangian particle hydrodynamics ( ulph ), to simulate the fluid - structure interaction problem in which large geometric deformation and material failure are considered. in the coupled framework, the nosb - pd theory is used to describe the deformation and fracture of the solid material structure. ulph is applied to describe the flow of newtonian fluids due to its advantages in computational accuracy. the framework effectively utilizes the advantages of nosb - pd theory for solving discontinuous problems and ulph theory for solving fluid problems and has good computational stability and robustness. to deal with the interface of fluid structure, a fluid - structure coupling algorithm using pressure as the transmission medium is established. the dynamic model of solid structure and the pd - ulph fluid - structure interaction model involving large deformation are verified by several numerical validations, which are in good agreement with the analytical solution, the available experimental data and other numerical results, that demonstrates the accuracy and effectiveness of the proposed method in solving the fluid - structure interaction problem. overall, the fluid - structure interaction model based on ulph and nosb - pd established in this paper provides a new idea for the numerical solution of fluid - structure interaction and a promising approach for engineering design and experimental prediction.
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arxiv:2312.05016
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the ` ` trans - planckian ' ' challenge in cosmology appears when we trace the present physical wavelengths of fluctuations backwards in time. they become smaller and smaller until crossing the planck scale where conventional qft is challenged, so that unknown ultraviolet physics may be traced in the observable cosmological fluctuations. usually this issue is addressed in the inflationary context, but trans - planckian reasoning is much broader. we examine this logic in a simple example of scalar quantum field theory in the expanding and contracting milne universes, where wavelengths of the eigenmodes are red - or blue - shifted. trans - planckian modifications of qft should result in a uv - dependent vev of the energy momentum tensor of a scalar field in the milne universe. on the other hand, the milne universe is another coordinate systems of flat minkowski space - time, and the covariant energy momentum tensor should be the same ( but vacuum - dependent ) in different coordinates of flat space time. we explicitly demonstrate that in conventional qft the energy momentum tensor, choosing the adiabatic vacuum, is identical to zero in minkowski coordinates, and remains zero in the contracting milne universe ( due to non - trivial cancellations of contributions from particles which appear in the accelerating frame and from vacuum polarization there ). in contrast to this, the trans - planckian modification of the energy momentum tensor is not motivated. we provide a similar argument for the expanding milne universe, where the energy momentum tensor in the conformal vacuum is non - zero. similar arguments are applicable for other cosmological models where the curvature is much lower than planckian which leads to conflicts with trans - planckian considerations.
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arxiv:0706.0980
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we report on a systematic characterization of microbulk micromegas readouts in high - pressure ar + 1 % ic4h10 and ne + 2 % ic4h10 mixtures. experimental data on gain, electron transmission and energy resolution are presented for a wide range of drift and amplification voltages and pressures from 1 bar to 10 bar for argon and from 5 bar to 10 bar in neon, in steps of 1 bar. maximum gains higher than 1. 7e3 ( 1. 7e4 ) in argon ( neon ) are measured for all pressures, remarkably without the significant decrease with pressure typically observed in other amplification structures. a competitive energy resolution at 22. 1 kev, but with a slight degradation with pressure, is observed : from 10. 8 % at 1 bar to 15. 6 % fwhm at 10 bar in argon and from 8. 3 % at 5 bar to 15. 0 % fwhm at1 10 bar in neon. the experimental setup, procedure and the results will be presented and discussed in detail. the work is motivated by the trex - dm experiment, that is operating in the laboratorio subterr \ ' aneo de canfranc with the mentioned mixtures, although the results may be of interest for other applications of time projection chambers at high pressures.
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arxiv:2204.08199
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the top flavour - changing neutral couplings can be large in extended models with vector - like quarks. in the next decade ( s ) the cern large hadron collider will allow to measure ( bound ) them with a precision of few per cent.
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arxiv:hep-ph/9911399
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