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the existence of stable links and knots is demonstrated in three - dimensional, bistable, chemical media. the reaction - diffusion medium segregates into regions of high and low concentration separated by sharp interfaces. the interfaces repel at short distances so that domains with various topologies are possible depending on the initial conditions and system parameters. front instabilities can give rise to knotted labyrinthine patterns. a lattice - gas model whose mean - field limit is the fitzhugh - nagumo equation is described and implemented to carry out the simulations. | arxiv:patt-sol/9606003 |
in the first part of this dissertation, i study the differences between locc ( local operations and classical communication ) and the more general class of separable operations. i show that the two classes coincide for the case of pure bipartite state input, and derive a set of important consequences. using similar techniques i also generalize the no - cloning theorem when restricted to separable operations and show that cloning becomes much more restrictive, by providing necessary ( and sometimes sufficient ) conditions. in the second part i investigate graph states and graph codes with carrier qudits of arbitrary dimensionality, and extend the notion of stabilizer to any dimension, not necessarily prime. i further study how and where information is located in the various subsets of the qudit carriers of arbitrary additive graph codes, and provide efficient techniques that can be used in deciding what types of information a subset contains. | arxiv:1006.4888 |
the effect of quark mass on the regge trajectory is analysed. modifications in the equations of regge trajectories are shown for mesonic as well as baryonic systems. for mesonic systems, the regge trajectories get modified, but still remain linear. contrary to the mesonic case, the regge trajectories for baryonic systems indicate non - linearity. it is shown that in low mass and angular momentum region two hadrons with different quark compositions can have same mass and angular momentum. | arxiv:1112.0731 |
radio pulsars are thought to born with spin periods of 0. 02 - 0. 5 s and space velocities of 100 - 1000 km / s, and they are inferred to have initial dipole magnetic fields of 10 ^ { 11 } - 10 ^ { 13 }. the average space velocity of a normal star in the milky way is only 30 km / s, which means that pulsars must receive a substantial ' kick ' at birth. here we propose that the birth characteristics of pulsars have a simple physical connection with each other. magnetic fields maintained by differential rotation between the core and envelope of the progenitor would keep the whole star in a state of approximately uniform rotation until 10 years before the explosion. such a slowly rotating core has 1000 times less angular momentum than required to explain the rotation of pulsars. although the specific physical process that ' kicks ' the neutron star at birth has not been identified, unless its force is exerted exactly head - on, it will also cause the neutron star to rotate. we identify this process as the origin of the spin of pulsars. such kicks will cause a correlation between the velocity and spin vectors of pulsars. we predict that many neutron stars are born with periods longer than 2 s, and never become radio pulsars. | arxiv:astro-ph/9803201 |
the following critical phenomenon was recently discovered. when a memoryless source is compressed using a variable - length fixed - distortion code, the fastest convergence rate of the ( pointwise ) compression ratio to the optimal $ r ( d ) $ bits / symbol is either $ o ( \ sqrt { n } ) $ or $ o ( \ log n ) $. we show it is always $ o ( \ sqrt { n } ) $, except for discrete, uniformly distributed sources. | arxiv:math/0009018 |
federated learning ( fl ) enables decentralized model training while preserving privacy. recently, integrating foundation models ( fms ) into fl has boosted performance but also introduced a novel backdoor attack mechanism. attackers can exploit the fm ' s capabilities to embed backdoors into synthetic data generated by fms used for model fusion, subsequently infecting all client models through knowledge sharing without involvement in the long - lasting fl process. these novel attacks render existing fl backdoor defenses ineffective, as they primarily detect anomalies among client updates, which may appear uniformly malicious under this attack. our work proposes a novel data - free defense strategy by constraining abnormal activations in the hidden feature space during model aggregation on the server. the activation constraints, optimized using synthetic data alongside fl training, mitigate the attack while barely affecting model performance, as the parameters remain untouched. extensive experiments demonstrate its effectiveness against both novel and classic backdoor attacks, outperforming existing defenses while maintaining model performance. | arxiv:2410.17573 |
the brilliant idea of jean betrema and jean - guy penaud that proved the celebrated " three to the power n " theorem of dominique gouyou - beauchamps and xavier viennot, counting towers of domino pieces is extended and used to enumerate much more general towers, where the pieces can be many i - mers. | arxiv:1212.4105 |
the effective approach in loop quantum cosmology ( lqc ) has provided means to obtain predictions for observable quantities in lqc models. while an effective dynamics in lqc has been extensively considered in different scenarios, a robust demonstration of the validity of effective descriptions for the perturbative level still requires further attention. the consistency of the description adopted in most approaches requires the assumption of a test field approximation, which is limited to the cases in which the backreaction of the particles gravitationally produced can be safely neglected. within the framework of lqc, some of the main approaches to quantize the linear perturbations are the dressed metric, the hybrid approaches and the closed / deformed algebra approach. here, we analyze the consistency of the test field assumption in these frameworks by computing the energy density stored in the particles gravitationally produced compared to the background energy density. this analysis ultimately provides us with a consistency test of the effective descriptions of lqc. | arxiv:2207.00435 |
phases of matter with robust ground - state degeneracy, such as the quantum toric code, are known to be capable of robust quantum information storage. here, we address the converse question : given a quantum error correcting code, when does it define a stable gapped quantum phase of matter, whose ground state degeneracy is robust against perturbations in the thermodynamic limit? we prove that a low - density parity - check ( ldpc ) code defines such a phase, robust against all few - body perturbations, if its code distance grows at least logarithmically in the number of degrees of freedom, and it exhibits " check soundness ". many constant - rate quantum ldpc expander codes have such properties, and define stable phases of matter with a constant zero - temperature entropy density, violating the third law of thermodynamics. our results also show that quantum toric code phases are robust to spatially nonlocal few - body perturbations. similarly, phases of matter defined by classical codes are stable against symmetric perturbations. in the classical setting, we present improved locality bounds on the quasiadiabatic evolution operator between two nearby states in the same code phase. | arxiv:2411.01002 |
in recent years, the mathematical limits and algorithmic bounds for probabilistic group testing have become increasingly well - understood, with exact asymptotic thresholds now being known in general scaling regimes for the noiseless setting. in the noisy setting where each test outcome is flipped with constant probability, there have been similar developments, but the overall understanding has lagged significantly behind the noiseless setting. in this paper, we substantially narrow this gap by deriving exact asymptotic thresholds for the noisy setting under two widely - studied random test designs : i. i. d. bernoulli and near - constant tests - per - item. these thresholds are established by combining components of an existing information - theoretic threshold decoder with a novel analysis of maximum - likelihood decoding ( upper bounds ), and deriving a novel set of impossibility results by analyzing certain failure events for optimal maximum - likelihood decoding ( lower bounds ). | arxiv:2401.04884 |
the microscopic origin of the remarkable optoelectronic properties of one of the most studied contemporary materials remains unclear. here, we identify the existence of magnetic interactions between intermolecular proton orbitals in ch $ _ 3 $ nh $ _ 3 $ pbi $ _ 3 $ and ch $ _ 3 $ nh $ _ 3 $ pbbr $ _ 3 $. in particular, a unique sharp drop and a pronounced step - up discontinuity in the magnetic susceptibility at the tetragonal - to - cubic phase transitions are identified in ch $ _ 3 $ nh $ _ 3 $ pbi $ _ 3 $ and ch $ _ 3 $ nh $ _ 3 $ pbbr $ _ 3 $, respectively. the magnetic interactions in the orthorhombic and tetragonal phases are dependent on thermal history and lattice orientation while nearly independent of the applied external magnetic field. in ch $ _ 3 $ nh $ _ 3 $ pbbr $ _ 3 $, the ch $ _ 3 $ and nh $ _ 3 $ $ ^ + $ components reorient in an uncorrelated fashion resulting the cubic phase to also exhibit magnetic anisotropy. our findings provide a potential link connecting the highly light - absorbing ch $ _ 3 $ nh $ _ 3 $ $ ^ + $ and the exceptional properties of the charge carriers of the inorganic framework in hybrid perovskite solar cells. | arxiv:2405.09094 |
we perform a systematic study of radiative corrections to the masses of the higgs bosons in the minimal supersymmetric standard model ( mssm ) augmented by a single gauge singlet, the so - called next - to - minimal supersymmetric standard model ( nmssm ). our method is based on the one - loop effective potential and includes effects of top quark, squark, higgs and higgsino loops. we discuss the renormalisation group flows of yukawa couplings and the upper bound on the lightest cp - even neutral higgs boson mass as a function of the heavier stop mass and top mass. we then give a general discussion of higgs boson phenomenology including radiative corrections. we survey as much of the parameter space of the higgs sector of the nmssm as is practicable, and analyse the full spectrum of higgs masses and couplings in these regions of parameter space. characteristic signatures of the nmssm such as light charged bosons and weakly coupled neutral scalars are discussed, as are the relative sizes of the various radiative corrections. the mssm is also discussed as a limiting case of the nmssm for comparison. | arxiv:hep-ph/9308309 |
the contribution from quantum vacuum fluctuations of a real massless scalar field to the motion of a test particle that interacts with the field in the presence of a perfectly reflecting flat boundary is here investigated. there is no quantum induced dispersions on the motion of the particle when it is alone in the empty space. however, when a reflecting wall is introduced, dispersions occur with magnitude dependent on how fast the system evolves between the two scenarios. a possible way of implementing this process would be by means of an idealized sudden switching, for which the transition occurs instantaneously. although the sudden process is a simple and mathematically convenient idealization it brings some divergences to the results, particularly at a time corresponding to a round trip of a light signal between the particle and the wall. it is shown that the use of smooth switching functions, besides regularizing such divergences, enables us to better understand the behavior of the quantum dispersions induced on the motion of the particle. furthermore, the action of modifying the vacuum state of the system leads to a change in the particle energy that depends on how fast the transition between these states is implemented. possible implications of these results to the similar case of an electric charge near a perfectly conducting wall are discussed. | arxiv:1709.10392 |
we examine and present new combinatorics for the schur polynomials from the viewpoint of quantum integrability. we introduce and analyze an integrable six - vertex model which can be viewed as a certain degeneration model from a t - deformed boson model. by a detailed analysis of the wavefunction from the quantum inverse scattering method, we present a novel combinatorial formula which expresses the schur polynomials by using an additional parameter, which is in the same sense but different from the tokuyama formula. we also give an algebraic analytic proof for the cauchy identity and make applications of the domain wall boundary partition functions to the enumeration of alternating sign matrices. | arxiv:1507.06740 |
the global ocean circulation plays a pivotal role in the regulation of the earth ' s climate. the specific pattern and strength of circulation also determines how carbon and nutrients are cycled and via the resulting distribution of dissolved oxygen, where habitats suitable for marine animals occur. however, evidence from both geological data and models suggests that state transitions in circulation patterns have occurred in the past. understanding the controls on marine environmental conditions and biodiversity requires a full appreciation of the nature and drivers of such transitions. here we present stable millennial oscillations of meridional overturning circulation in an earth system model of intermediate complexity, cgenie, that appear to only occur in the presence of a circumpolar current. to demonstrate that a circumpolar current can act as a driver of stable oscillations, we adapt a simple ocean box model to include a delayed feedback to represent the effect of a circumpolar current on meridional overturning circulation. we investigate the millennial oscillatory solutions that arise in the box model by bifurcation analysis and show that the model can reproduce the same bifurcation structure observed in the earth system model. our results provide new insights into the nature of oscillations that could have occurred under certain continental configurations in the geological past, and also highlight the potential influence of the changing antarctic circumpolar current speed on the stability of the atlantic meridional overturning circulation. | arxiv:2201.07883 |
an update on recent discoveries by the icecube project, which transforms approximately one cubic kilometer of natural antarctic ice into a cherenkov detector. this paper will be submitted to slac for inclusion in the snowmass2013 proceedings | arxiv:1308.3171 |
we present the numerical solution of the renormalization group ( rg ) equations derived in ref. [ 1 ], for the problem of superconductivity in the presence of both electron - electron and electron - phonon coupling at zero temperature. we study the instability of a fermi liquid to a superconductor and the rg flow of the couplings in presence of retardation effects and the crossover from weak to strong coupling. we show that our numerical results provide an ansatz for the analytic solution of the problem in the asymptotic limits of weak and strong coupling. | arxiv:cond-mat/0505426 |
the negative energy density of casimir systems appears to violate general relativity energy conditions. however, one cannot test the averaged null energy condition ( anec ) using standard calculations for perfectly reflecting plates, because the null geodesic would have to pass through the plates, where the calculation breaks down. to avoid this problem, we compute the contribution to anec for a geodesic that passes through a hole in a single plate. we consider both dirichlet and neumann boundary conditions in two and three space dimensions. we use a babinet ' s principle argument to reduce the problem to a complementary finite disk correction to the perfect mirror result, which we then compute using scattering theory in elliptical and spheroidal coordinates. in the dirichlet case, we find that the positive correction due to the hole overwhelms the negative contribution of the infinite plate. in the neumann case, where the infinite plate gives a positive contribution, the hole contribution is smaller in magnitude, so again anec is obeyed. these results can be extended to the case of two plates in the limits of large and small hole radii. this system thus provides another example of a situation where anec turns out to be obeyed when one might expect it to be violated. | arxiv:hep-th/0506136 |
fully depleted monolithic active pixels ( fd - maps ) represent a state - of - the - art detector technology and profit from a low material budget and cost for high energy physics experiments and other fields of research like medical imaging and astro - particle physics. compared to the maps currently in use, fully depleted pixel sensors have the advantage of charge collection by drift, which enables a fast and uniform response overall the pixel matrix. the functionality of these devices has been shown in previous proof - of - concept productions. in this article we describe the optimization of the test pixel designs, that will be implemented in the first engineering run of the demonstrator chip of the arcadia project. these optimization procedures include radiation damage models, that have been employed in technology computer aided design simulations to predict the sensors behavior in different working environments. | arxiv:2011.09723 |
we study the center of the two - parameter quantum supergroup $ u _ { r, s } ( osp ( 1, 2 ) ) $ using the dickson polynomial. we show that the scasimir operator is completely determined by the $ q $ - deformed chebychev polynomial, generalizing an earlier work of arnaudon and bauer. | arxiv:2210.00288 |
judge ' s further development of these ideas | https://en.wikipedia.org/wiki/Unified_Science |
we present a detailed analysis of a quantum model for loop quantum cosmology based on strict application of the thiemann regularization algorithm for the hamiltonian in loop quantum gravity, extending the results presented previously in our brief report. this construction leads to a qualitative modification of the bounce paradigm. quantum gravity effects still lead to a quantum bounce connecting deterministically large classical universes. however, the evolution features a large epoch of de sitter universe, with emergent cosmological constant of planckian order, smoothly transiting into a spatially flat expanding universe. moreover, we present an effective hamiltonian describing the quantum evolution to high accuracy and for which the dynamics can be solved analytically. | arxiv:1906.05315 |
in a recent study [ c arita, phys. rev. e 80, 051119 ( 2009 ) ], an extension of the m / m / 1 queueing process with the excluded - volume effect as in the totally asymmetric simple exclusion process ( tasep ) was introduced. in this paper, we consider its discrete - time version. the update scheme we take is the parallel one. a stationary - state solution is obtained in a slightly arranged matrix product form of the discrete - time open tasep with the parallel update. we find the phase diagram for the existence of the stationary state. the critical line which separates the parameter space into the regions with and without the stationary state can be written in terms of the stationary current of the open tasep. we calculate the average length of the system and the average number of particles. | arxiv:1008.4651 |
we study the percolation transition in growing networks under an achlioptas process ( ap ). at each time step, a node is added in the network and, with the probability $ \ delta $, a link is formed between two nodes chosen by an ap. we find that there occurs the percolation transition with varying $ \ delta $ and the critical point $ \ delta _ c = 0. 5149 ( 1 ) $ is determined from the power - law behavior of order parameter and the crossing of the fourth - order cumulant at the critical point, also confirmed by the movement of the peak positions of the second largest cluster size to the $ \ delta _ c $. using the finite - size scaling analysis, we get $ \ beta / \ bar { \ nu } = 0. 20 ( 1 ) $ and $ 1 / \ bar { \ nu } = 0. 40 ( 1 ) $, which implies $ \ beta \ approx 1 / 2 $ and $ \ bar { \ nu } \ approx 5 / 2 $. the fisher exponent $ \ tau = 2. 24 ( 1 ) $ for the cluster size distribution is obtained and shown to satisfy the hyperscaling relation. | arxiv:1305.5377 |
text - video retrieval plays an important role in multi - modal understanding and has attracted increasing attention in recent years. most existing methods focus on constructing contrastive pairs between whole videos and complete caption sentences, while overlooking fine - grained cross - modal relationships, e. g., clip - phrase or frame - word. in this paper, we propose a novel method, named hierarchical cross - modal interaction ( hcmi ), to explore multi - level cross - modal relationships among video - sentence, clip - phrase, and frame - word for text - video retrieval. considering intrinsic semantic frame relations, hcmi performs self - attention to explore frame - level correlations and adaptively cluster correlated frames into clip - level and video - level representations. in this way, hcmi constructs multi - level video representations for frame - clip - video granularities to capture fine - grained video content, and multi - level text representations at word - phrase - sentence granularities for the text modality. with multi - level representations for video and text, hierarchical contrastive learning is designed to explore fine - grained cross - modal relationships, i. e., frame - word, clip - phrase, and video - sentence, which enables hcmi to achieve a comprehensive semantic comparison between video and text modalities. further boosted by adaptive label denoising and marginal sample enhancement, hcmi achieves new state - of - the - art results on various benchmarks, e. g., rank @ 1 of 55. 0 %, 58. 2 %, 29. 7 %, 52. 1 %, and 57. 3 % on msr - vtt, msvd, lsmdc, didemo, and activitynet, respectively. | arxiv:2204.03382 |
deep learning methods have achieved impressive performance for multi - class medical image segmentation. however, they are limited in their ability to encode topological interactions among different classes ( e. g., containment and exclusion ). these constraints naturally arise in biomedical images and can be crucial in improving segmentation quality. in this paper, we introduce a novel topological interaction module to encode the topological interactions into a deep neural network. the implementation is completely convolution - based and thus can be very efficient. this empowers us to incorporate the constraints into end - to - end training and enrich the feature representation of neural networks. the efficacy of the proposed method is validated on different types of interactions. we also demonstrate the generalizability of the method on both proprietary and public challenge datasets, in both 2d and 3d settings, as well as across different modalities such as ct and ultrasound. code is available at : https : / / github. com / topoxlab / topointeraction | arxiv:2207.09654 |
we investigate two destabilization mechanisms for elastic polymer films and put them into a general framework : first, instabilities due to in - plane stress and second due to an externally applied electric field normal to the film ' s free surface. as shown recently, polymer films are often stressed due to out - of - equilibrium fabrication processes as e. g. spin coating. via an asaro - tiller - grinfeld mechanism as known from solids, the system can decrease its energy by undulating its surface by surface diffusion of polymers and thereby relaxing stresses. on the other hand, application of an electric field is widely used experimentally to structure thin films : when the electric maxwell surface stress overcomes surface tension and elastic restoring forces, the system undulates with a wavelength determined by the film thickness. we develop a theory taking into account both mechanisms simultaneously and discuss their interplay and the effects of the boundary conditions both at the substrate and the free surface. | arxiv:1009.4066 |
this paper answers the conjecture of adimurthi and struwe that the semilinear trudinger - moser functional ( as well as functionals with more general critical nonlinearities ) satisfies the palais - smale condition at all levels except n / 2 for integer n. in this paper we construct critical sequences at any level greater than 1 / 2 corresponding to a large family of distinct concentration profiles, indexed by all closed subsets c of ( 0, 1 ) that arise in the two - dimensional case instead of the " standard bubble " in higher dimensions. the approach is based on the profile decomposition in the style of solimini. | arxiv:1211.3835 |
using an analytic model calibrated against numerical simulations, we calculate the central densities of dark matter halos in a ` ` conventional ' ' cold dark matter model with a cosmological constant ( lcdm ) and in a ` ` tilted ' ' model ( tlcdm ) with slightly modified parameters motivated by recent analyses of ly - alpha forest data. we also calculate how warm dark matter ( wdm ) would modify these predicted densities by delaying halo formation and imposing phase space constraints. as a measure of central density, we adopt the quantity d _ { v / 2 }, the density within the radius r _ { v / 2 } at which the halo rotation curve falls to half of its maximum value, in units of the critical density. we compare the theoretical predictions to values of d _ { v / 2 } estimated from the rotation curves of dark matter dominated disk galaxies. assuming that dark halos are described by nfw profiles, our results suggest that the conventional lcdm model predicts excessively high dark matter densities, unless there is some selection bias in the data toward the low - concentration tail of the halo distribution. a wdm model with particle mass 0. 5 - 1 kev provides a better match to the observational data. however, the modified cold dark matter model, tlcdm, fits the data equally well, suggesting that the solution to the ` ` halo cores ' ' problem might lie in moderate changes to cosmological parameters rather than radical changes to the properties of dark matter. if cdm halos have the steeper density profiles found by moore et al., then neither conventional lcdm nor tlcdm can reproduce the observed central densities. | arxiv:astro-ph/0109392 |
aiming at studying the mechanism of photo - excited precession of magnetization in ferromagnetic ( ga, mn ) as, magneto - optical ( mo ) and differential reflectivity ( dr ) temporal profiles are studied at relatively long and ultra - short time scales for samples with different mn contents ( x = 0. 01 - 0. 11 ). as to the oscillatory mo profiles observed in the long time scale, simulation based on the llg equation combined with two different mo effects confirms photo - inducement of the perpendicular anisotropy component p - heff. as for the profiles observed in the ultra - short time scale, they are consistently explained in terms of the dynamics of photo - generated carriers, but not by the sudden reduction in magnetization. with those experimental results and analyses, new mechanism which accounts for the photo - induced p - heff is addressed ; photo - ionization like excitation of mn ( ii ). namely, mn ( ii ) is excited into mn ( iii ) and e. it is discussed that such excitation tips magnetic anisotropy toward the out - of - plane direction through the inducement of orbital angular momentum and the gradient dmn ( ii * ) / dz. validity of the proposed mechanism is examined by estimating the efficiency of excitation on the basis of the lambert - beer law and the experimental p - heff values, through which the efficiency of 1 - 10 ppm with the nominal optical cross section of around 5 x 10 ^ 12 m ^ 2 are obtained. | arxiv:1510.01587 |
the einstein - hilbert action has a bulk term and a surface term ( which arises from integrating a four divergence ). i show that one can obtain einstein ' s equations from the surface term alone. this leads to : ( i ) a novel, completely self contained, perspective on gravity and ( ii ) a concrete mathematical framework in which the description of spacetime dynamics by einstein ' s equations is similar to the description of a continuum solid in the thermodynamic limit. | arxiv:gr-qc/0510015 |
magnetization reversal mechanisms and impact of magnetization direction are studied in square arrays of interconnected circular permalloy nanorings using moke, local imaging, numerical simulations and transport techniques. | arxiv:cond-mat/0604132 |
the nature and the location of the lenses discovered in the microlensing surveys done so far towards the lmc remain unclear. motivated by these questions we compute the optical depth and particularly the number of expected events for self - lensing for both the macho and eros2 observations. we calculate these quantities also for other possible lens populations such as thin and thick disk and galactic spheroid. moreover, we estimate for each of these components the corresponding average event duration and mean mass using the mass moment method. by comparing the theoretical quantities with the values of the observed events it is possible to put some constraints on the location and the nature of the machos. clearly, given the large uncertainties and the few events at disposal it is not possible to draw sharp conclusions, nevertheless we find that certainly at least 3 - 4 macho events are due to lenses in lmc, which are most probably low mass stars, but that hardly all events can be due to self - lensing. this conclusions is even stronger when considering the eros2 events, due to their spatial distribution. the most plausible solution is that the events observed so far are due to lenses belonging to different intervening populations : low mass stars in the lmc, in the thick disk, in the spheroid and possibly some true machos in the halo. | arxiv:astro-ph/0207252 |
we introduce and study maker / breaker - type positional games on random graphs. our main concern is to determine the threshold probability $ p _ { f } $ for the existence of maker ' s strategy to claim a member of $ f $ in the unbiased game played on the edges of random graph $ g ( n, p ) $, for various target families $ f $ of winning sets. more generally, for each probability above this threshold we study the smallest bias $ b $ such that maker wins the $ ( 1 \ : b ) $ biased game. we investigate these functions for a number of basic games, like the connectivity game, the perfect matching game, the clique game and the hamiltonian cycle game. | arxiv:math/0601659 |
the study of identified particle production in proton - proton ( pp ) collisions as a function of center - of - mass energy ( $ \ sqrt { s } $ ) and event charged - particle multiplicity is a key tool for understanding similarities and differences between small and large collision systems. we report on new measurements of the production of identified particles and their dependence on multiplicity and $ \ sqrt { s } $. latest results for light flavor hadrons, comprising $ \ pi ^ { \ pm } $, $ \ mathrm { k } ^ { \ pm } $, $ { \ rm p } ( \ rm \ bar { p } ) $, single - strange ( $ \ mathrm { k _ { s } ^ { 0 } } $, $ \ bar { \ lambda } $, and $ \ lambda $ ), multi - strange ( $ \ xi ^ { - } $, $ \ overline { \ xi } ^ { + } $, $ \ omega ^ { - } $, and $ \ overline { \ omega } ^ { + } $ ) particles as well as resonances ( $ \ mathrm { k ^ { * 0 } } $, $ \ mathrm { \ overline { k } ^ { * 0 } } $, $ \ phi $ ), are presented for $ \ sqrt { s } ~ = ~ 5. 02, 7 $, and 13 tev. the measured minimum bias $ p _ { \ rm t } $ spectra and yields were complemented with multiplicity - dependent measurements for single - and multi - strange hadrons at $ \ sqrt { s } ~ = ~ 7 $ and $ \ sqrt { s } ~ = ~ 13 $ tev. results are compared to measurements at lower $ \ sqrt { s } $ as well as to those in proton - lead and lead - lead ( pb - pb ) collisions, respectively at $ \ sqrt { s } _ { \ rm nn } ~ = ~ 5. 02 $ tev and $ \ sqrt { s } _ { \ rm nn } ~ = ~ 2. 76 $ tev. the results unveil intriguing similarities among collision systems at different $ \ sqrt { s } $. the production rates of strange hadrons are found to increase more than those of non - strange particles, showing an enhancement pattern with multiplicity which does not depend on the collision energy. these yield ratios take values which are alike for small systems at | arxiv:1801.03350 |
we use a coarse - grained molecular dynamics model to study the electrophoretic behaviour of flexible polyelectrolyte chains. we first characterize the static properties of the model with respect to the chain length, the polyelectrolyte concentration, additional salt and the influence of an applied external field. next we investigate the dynamic behaviour in the oligomer range and compare to data obtained by two different experimental methods, namely capillary electrophoresis and pfg - nmr. we find excellent agreement of experiments and simulations when hydrodynamic interactions are accounted for in the simulations. we then present novel estimators for the dynamical effective charge during free solution electrophoresis and compare them to static estimators. we find complete agreement between the static and the dynamic estimators. we further evaluate the scaling behaviour of the effective friction of the polyelectrolyte - counterion complex with the surrounding fluid. we identify a hydrodynamic screening length beyond which the friction during electrophoresis is linear depending on the chain length resulting in a constant mobility for long polyelectrolyte chains. our results show a convincing agreement with experimental data and demonstrate that it is possible to model dynamic behaviour of polyelectrolytes using coarse grained models, provided they include the effects of hydrodynamical interactions. | arxiv:0812.2557 |
in this article we identify a sharp ill - posedness / well - posedness threshold for kinetic wave equations ( kwe ) derived from quasilinear schr \ " { o } dinger models. we show well - posedness using a collisional averaging estimate proved in our earlier work \ cite { amle }. ill - posedness manifests as instantaneous loss of smoothness for well - chosen initial data. we also prove that both the gain - only and full equation share the same well - posedness threhold, thus legitimizing a gain - only approach to solving 4 - wave kinetic equations. | arxiv:2411.12868 |
we demonstrate the sensitivity of transverse - field muon spin rotation ( tf - musr ) to static charge - density - wave ( cdw ) order in the bulk of 2h - nbse2. in the presence of cdw order the quadrupolar interaction of the 93nb nuclei with the local electric - field gradient is modified, and this in turn affects the magnetic dipolar coupling of the positive muon to these nuclei. for a weak magnetic field applied parallel to the c - axis, we observe a small enhancement of the muon depolarization rate at temperatures below the established cdw phase transition. aligning the applied field perpendicular to the c - axis, we observe a sensivity to static cdw order in regions of the sample extending up to nearly 3 times the cdw transition temperature. the results suggest that the muon is mobile over the temperature range explored above the superconducting transition temperature ( tc ), and becomes trapped in the vicinity of defects. | arxiv:1505.00839 |
we use the field theory description of the fractional quantum hall states to derive the universal response of these topological fluids to shear deformations and curvature of their background geometry, i. e. the hall viscosity, the wen - zee term, and the gravitational chern - simons term. to account for the coupling to the background geometry, we show that the concept of flux attachment needs to be modified and use it to derive the geometric responses from chern - simons theories. we show that the resulting composite particles minimally couple to the spin connection of the geometry. we derive a consistent theory of geometric responses from the chern - simons effective field theories and from parton constructions, and apply it to both abelian and non - abelian states. | arxiv:1406.2700 |
we propose a fourth - order unfitted characteristic finite element method to solve the advection - diffusion equation on time - varying domains. based on a characteristic - galerkin formulation, our method combines the cubic mars method for interface tracking, the fourth - order backward differentiation formula for temporal integration, and an unfitted finite element method for spatial discretization. our convergence analysis includes errors of discretely representing the moving boundary, tracing boundary markers, and the spatial discretization and the temporal integration of the governing equation. numerical experiments are performed on a rotating domain and a severely deformed domain to verify our theoretical results and to demonstrate the optimal convergence of the proposed method. | arxiv:2104.01870 |
a dual formulation for the problem of determining absolute performance limitations on overshoot, undershoot, maximum amplitude and fluctuation minimization for continuous - time feedback systems is constructed. determining, for example, the minimum possible overshoot attainable by all possible stabilizing controllers is an optimization task that cannot be expressed as a minimum - norm problem. it is this fact, coupled with the continuous - time rather than discrete - time formulation, that makes these problems challenging. we extend previous results to include more general reference functions, and derive new results ( in continuous time ) on the influence of pole / zero locations on achievable time - domain performance. | arxiv:1103.4198 |
topological spin textures have attracted much attention both for fundamental physics and spintronics applications. among them, antiskyrmions possess a unique spin configuration with bloch - type and n \ ' eel - type domain walls due to anisotropic dzyaloshinskii - moriya interaction ( dmi ) in the noncentrosymmetric crystal structure. however, antiskyrmions have thus far only been observed in a few heusler compounds with $ d _ { 2 \ mathrm { d } } $ symmetry. here, we report a new material fe $ _ { 1. 9 } $ ni $ _ { 0. 9 } $ pd $ _ { 0. 2 } $ p in a different symmetry class ( $ s _ 4 $ symmetry ), where antiskyrmions exist over a wide temperature region including room temperature, and transform to skyrmions upon changing magnetic field and lamella thickness. the periodicity of magnetic textures greatly depends on crystal thickness, and domains with anisotropic sawtooth fractals are observed at the surface of thick crystals, which are attributed to the interplay between dipolar interaction and dmi as governed by crystal symmetry. our findings provide a new arena to study antiskyrmions, and should stimulate further research on topological spin textures and their applications. | arxiv:2101.12359 |
we use the klein - gordon equation in a curved spacetime to construct the relativistic analog of the schr \ " odinger - newton problem, where a scalar particle lives in a gravitational potential well generated by its own probability distribution. a static, spherically symmetric metric is computed from the field equations of general relativity, both directly and as modeled by a perfect - fluid assumption that uses the tolman - oppenheimer - volkov equation for hydrostatic equilibrium of the mass density. the latter is appropriate for a hartree approximation to the many - body problem of a bosonic star. simultaneous self - consistent solution of the klein - - gordon equation in this curved spacetime then yields solitons with a range of radial excitations. we compare results with the nonrelativistic case. | arxiv:2212.14166 |
nuclear jets containing relativistic ` ` hot ' ' particles close to the central engine cool dramatically by producing high energy radiation. the radiative dissipation is similar to the famous compton drag acting upon ` ` cold ' ' thermal particles in a relativistic bulk flow. highly relativistic protons induce anisotropic showers raining electromagnetic power down onto the putative accretion disk. thus, the radiative signature of hot hadronic jets is x - ray irradiation of cold thermal matter. the synchrotron radio emission of the accelerated electrons is self - absorbed due to the strong magnetic fields close to the magnetic nozzle. | arxiv:astro-ph/9309058 |
distribution and distillation of entanglement over quantum networks is a basic task for quantum internet applications. a fundamental question is then to determine the ultimate performance of entanglement distribution over a given network. although this question has been extensively explored for bipartite entanglement - distribution scenarios, less is known about multipartite entanglement distribution. here we establish the fundamental limit of distributing multipartite entanglement, in the form of ghz states, over a quantum network. in particular, we determine the multipartite entanglement distribution capacity of a quantum network, in which the nodes are connected through lossy bosonic quantum channels. this setting corresponds to a practical quantum network consisting of optical links. the result is also applicable to the distribution of multipartite secret key, known as common key, for both a fully quantum network and trusted - node based quantum key distribution network. our results set a general benchmark for designing a network topology and network quantum repeaters ( or key relay in trusted nodes ) to realize efficient ghz state / common key distribution in both fully quantum and trusted - node - based networks. we show an example of how to overcome this limit by introducing a network quantum repeater. our result follows from an upper bound on distillable ghz entanglement introduced here, called the " recursive - cut - and - merge " bound, which constitutes major progress on a longstanding fundamental problem in multipartite entanglement theory. this bound allows for determining the distillable ghz entanglement for a class of states consisting of products of bipartite pure states. | arxiv:1912.10658 |
topological data analysis ( tda ) provides insight into data shape. the summaries obtained by these methods are principled global descriptions of multi - dimensional data whilst exhibiting stable properties such as robustness to deformation and noise. such properties are desirable in deep learning pipelines but they are typically obtained using non - tda strategies. this is partly caused by the difficulty of combining tda constructs ( e. g. barcode and persistence diagrams ) with current deep learning algorithms. fortunately, we are now witnessing a growth of deep learning applications embracing topologically - guided components. in this survey, we review the nascent field of topological deep learning by first revisiting the core concepts of tda. we then explore how the use of tda techniques has evolved over time to support deep learning frameworks, and how they can be integrated into different aspects of deep learning. furthermore, we touch on tda usage for analyzing existing deep models ; deep topological analytics. finally, we discuss the challenges and future prospects of topological deep learning. | arxiv:2302.03836 |
many real world scientific and industrial applications require optimizing multiple competing black - box objectives. when the objectives are expensive - to - evaluate, multi - objective bayesian optimization ( bo ) is a popular approach because of its high sample efficiency. however, even with recent methodological advances, most existing multi - objective bo methods perform poorly on search spaces with more than a few dozen parameters and rely on global surrogate models that scale cubically with the number of observations. in this work we propose morbo, a scalable method for multi - objective bo over high - dimensional search spaces. morbo identifies diverse globally optimal solutions by performing bo in multiple local regions of the design space in parallel using a coordinated strategy. we show that morbo significantly advances the state - of - the - art in sample efficiency for several high - dimensional synthetic problems and real world applications, including an optical display design problem and a vehicle design problem with 146 and 222 parameters, respectively. on these problems, where existing bo algorithms fail to scale and perform well, morbo provides practitioners with order - of - magnitude improvements in sample efficiency over the current approach. | arxiv:2109.10964 |
offline batch inference is a common task in the industry for deep learning applications, but it can be challenging to ensure stability and performance when dealing with large amounts of data and complicated inference pipelines. this paper demonstrated antbatchinfer, an elastic batch inference framework, which is specially optimized for the non - dedicated cluster. antbatchinfer addresses these challenges by providing multi - level fault - tolerant capabilities, enabling the stable execution of versatile and long - running inference tasks. it also improves inference efficiency by pipelining, intra - node, and inter - node scaling. it further optimizes the performance in complicated multiple - model batch inference scenarios. through extensive experiments and real - world statistics, we demonstrate the superiority of our framework in terms of stability and efficiency. in the experiment, it outperforms the baseline by at least $ 2 \ times $ and $ 6 \ times $ in the single - model or multiple - model batch inference. also, it is widely used at ant group, with thousands of daily jobs from various scenarios, including dlrm, cv, and nlp, which proves its practicability in the industry. | arxiv:2404.09686 |
significant deviations from the standard model are observed in semileptonic charged and neutral - current b - decays, the muon magnetic moment, and the extraction of the cabibbo angle. we propose that these deviations point towards a coherent pattern of new physics effects induced by two scalar mediators, a leptoquark $ s _ 1 $ and a charged singlet $ \ phi ^ + $. while $ s _ 1 $ can provide solutions to charged - current $ b $ - decays and the muon magnetic moment, and $ \ phi ^ + $ can accommodate the cabibbo - angle anomaly independently, their one - loop level synergy can also address neutral - current $ b $ - decays. this framework provides the most minimal explanation to the above - mentioned anomalies, while being consistent with all other phenomenological constraints. | arxiv:2104.05730 |
this article presents a set of spectro - goniometric measurements of different water ice samples and the comparison with an approximated radiative transfer model. the experiments were done using the spectro - radiogoniometer described in brissaud et al. ( 2004 ). the radiative transfer model assumes an isotropization of the flux after the second interface and is fully described in andrieu et al. ( 2015 ). two kind of experiments were conducted. first, the specular spot was closely investigated, at high angular resolution, at the wavelength of $ 1. 5 \, \ mbox { \ mu m } $, where ice behaves as a very absorbing media. second, the bidirectional reflectance was sampled at various geometries, including low phase angles on 61 wavelengths ranging from $ 0. 8 \, \ mbox { \ mu m } $ to $ 2. 0 \, \ mbox { \ mu m } $. in order to validate the model, we made a qualitative test to demonstrate the relative isotropization of the flux. we also conducted quantitative assessments by using a bayesian inversion method in order to estimate the parameters ( e. g. sample thickness, surface roughness ) from the radiative measurements only. a simple comparison between the retrieved parameters and the direct independent measurements allowed us to validate the model. we developed an innovative bayesian inversion approach to quantitatively estimate the uncertainties on the parameters avoiding the usual slow monte carlo approach. first we built lookup tables, and then searched the best fits and calculated a posteriori density probability functions. the results show that the model is able to reproduce the spectral behavior of water ice slabs, as well as the specular spot. in addition, the different parameters of the model are compatible with independent measurements. | arxiv:1507.04241 |
domain adaptation enables the learner to safely generalize into novel environments by mitigating domain shifts across distributions. previous works may not effectively uncover the underlying reasons that would lead to the drastic model degradation on the target task. in this paper, we empirically reveal that the erratic discrimination of the target domain mainly stems from its much smaller feature norms with respect to that of the source domain. to this end, we propose a novel parameter - free adaptive feature norm approach. we demonstrate that progressively adapting the feature norms of the two domains to a large range of values can result in significant transfer gains, implying that those task - specific features with larger norms are more transferable. our method successfully unifies the computation of both standard and partial domain adaptation with more robustness against the negative transfer issue. without bells and whistles but a few lines of code, our method substantially lifts the performance on the target task and exceeds state - of - the - arts by a large margin ( 11. 5 % on office - home and 17. 1 % on visda2017 ). we hope our simple yet effective approach will shed some light on the future research of transfer learning. code is available at https : / / github. com / jihanyang / afn. | arxiv:1811.07456 |
. archived from the original on 15 january 2018. | https://en.wikipedia.org/wiki/Mathematicism |
we consider a class of convergence questions for infinite products that arise in wavelet theory when the wavelet filters are more singular than is traditionally built into the assumptions. we establish pointwise convergence properties for the absolute square of the scaling functions. our proofs are based on probabilistic tools. | arxiv:math/0506465 |
the damping rates of high quality factor nanomechanical resonators are well beyond intrinsic limits. here, we explore the underlying microscopic loss mechanisms by investigating the temperature - dependent damping of the fundamental and third harmonic transverse flexural mode of a doubly clamped silicon nitride string. it exhibits characteristic maxima reminiscent of two - level defects typical for amorphous materials. coupling to those defects relaxes the momentum selection rules, allowing energy transfer from discrete long wavelength resonator modes to the high frequency phonon environment. | arxiv:1310.3671 |
particle production from vacuum fluctuations during inflation is briefly revisited. the moduli problem occurring with light particles produced at the end of inflation is addressed, namely the fact that some results are in disagreement with nucleosynthesis constrains. a universal solution to this problem is found which leads to reasonable reheating temperatures in all cases. it invokes the assumption that, immediately after inflation, the moduli evolve like non - relativistic matter. the assumption is justified in the context of massive chaotic inflation were, at the end of inflation, the universe evolves as if it was matter - dominated. | arxiv:1201.1227 |
we compute the two - loop bsm contributions to the $ h \ longrightarrow \ gamma \ gamma $ decay width in the sm extended with a real triplet of $ su ( 2 ) $. we consider scenarios in which the neutral components of doublet and triplet do not mix, so that the lighter neutral scalar $ h $ has ( at least approximately ) sm - like couplings to fermions and gauge bosons. we focus on the two - loop corrections controlled by the quartic scalar couplings, and obtain explicit and compact formulas for the $ h \ gamma \ gamma $ amplitude by means of a low - energy theorem that connects it to the derivative of the photon self - energy w. r. t. the higgs field. we briefly discuss the numerical impact of the newly - computed contributions, showing that they may be required for a precise determination of $ \ gamma [ h \ rightarrow \ gamma \ gamma ] $ in scenarios where the quartic scalar couplings are large. | arxiv:2407.18185 |
several new generation experiments searching for neutrinoless double beta decay ( 0vbb ) have become operational over the last five years. this report summarizes the present status of the experimental search and discusses peculiarities, challenges and reached half - life limits / sensitivities in these experiments. so far, no evidence for 0vbb has been found. starting from the current situation, the paper addresses the question whether an experiment alone will be able to proof unambiguously 0vbb decay and which would be the key - requirements to succeed in this. | arxiv:1704.08537 |
context : the success of quickcheck has led to the development of property - based testing ( pbt ) libraries for many languages and the process is getting increasing attention. however, unlike regular testing, pbt is not widespread in collegiate curricula. furthermore, the value of pbt is not limited to software testing. the growing use of formal methods in, and the growth of software synthesis, all create demand for techniques to train students and developers in the art of specification writing. we posit that pbt forms a strong bridge between testing and the act of specification : it ' s a form of testing where the tester is actually writing abstract specifications. inquiry : even well - informed technologists mention the difficulty of finding good motivating examples for its use. we take steps to fill this lacuna. approach & knowledge : we find that the use of " relational " problems - - those for which an input may admit multiple valid outputs - - easily motivates the use of pbt. we also notice that such problems are readily available in the computer science pantheon of problems ( e. g., many graph and sorting algorithms ). we have been using these for some years now to teach pbt in collegiate courses. grounding : in this paper, we describe the problems we use and report on students? completion of them. we believe the problems overcome some of the motivation issues described above. we also show that students can do quite well at pbt for these problems, suggesting that the topic is well within their reach. in the process, we introduce a simple method to evaluate the accuracy of their specifications, and use it to characterize their common mistakes. importance : based on our findings, we believe that relational problems are an underutilized motivating example for pbt. we hope this paper initiates a catalog of such problems for educators ( and developers ) to use, and also provides a concrete ( though by no means exclusive ) method to analyze the quality of pbt. | arxiv:2010.16305 |
runge - kutta ( rk ) methods may exhibit order reduction when applied to certain stiff problems. while fully implicit rk schemes exist that avoid order reduction via high - stage order, dirk ( diagonally implicit runge - kutta ) schemes are practically important due to their structural simplicity ; however, these cannot possess high stage order. the concept of weak stage order ( wso ) can also overcome order reduction, and it is compatible with the dirk structure. dirk schemes of wso up to 3 have been proposed in the past, however, based on a simplified framework that cannot be extended beyond wso 3. in this work a general theory of wso is employed to overcome the prior wso barrier and to construct practically useful high - order dirk schemes with wso 4 and above. the resulting dirk schemes are stiffly accurate, l - stable, have optimized error coefficients, and are demonstrated to perform well on a portfolio of relevant ode and pde test problems. | arxiv:2204.11264 |
we investigate the electroweak form factors and semileptonic decay rates of mesons using the constituent quark model based on the light - front degrees of freedom. our results demonstrate the broader applicability of light - front approach including the timelike region of exclusive processes. | arxiv:hep-ph/9908431 |
the authors use riemann - hilbert methods to compute the constant that arises in the asymptotic behavior of the airy - kernel determinant of random matrix theory. | arxiv:math/0609451 |
consider a scheduling problem in which jobs need to be processed on a single machine. each job has a weight and is composed of several operations belonging to different families. the machine needs to perform a setup between the processing of operations of different families. a job is completed when its latest operation completes and the goal is to minimize the total weighted completion time of all jobs. we study this problem from the perspective of approximability and provide constant factor approximations as well as an inapproximability result. prior to this work, only the np - hardness of the unweighted case and the polynomial solvability of a certain special case were known. | arxiv:1910.08360 |
and bad nvh qualities. the nvh engineer works to either eliminate bad nvh or change the " bad nvh " to good ( i. e., exhaust tones ). vehicle electronics : automotive electronics is an increasingly important aspect of automotive engineering. modern vehicles employ dozens of electronic systems. these systems are responsible for operational controls such as the throttle, brake and steering controls ; as well as many comfort - and - convenience systems such as the hvac, infotainment, and lighting systems. it would not be possible for automobiles to meet modern safety and fuel - economy requirements without electronic controls. performance : performance is a measurable and testable value of a vehicle ' s ability to perform in various conditions. performance can be considered in a wide variety of tasks, but it generally considers how quickly a car can accelerate ( e. g. standing start 1 / 4 mile elapsed time, 0 – 60 mph, etc. ), its top speed, how short and quickly a car can come to a complete stop from a set speed ( e. g. 70 - 0 mph ), how much g - force a car can generate without losing grip, recorded lap - times, cornering speed, brake fade, etc. performance can also reflect the amount of control in inclement weather ( snow, ice, rain ). shift quality : shift quality is the driver ' s perception of the vehicle to an automatic transmission shift event. this is influenced by the powertrain ( internal combustion engine, transmission ), and the vehicle ( driveline, suspension, engine and powertrain mounts, etc. ) shift feel is both a tactile ( felt ) and audible ( heard ) response of the vehicle. shift quality is experienced as various events : transmission shifts are felt as an upshift at acceleration ( 1 – 2 ), or a downshift maneuver in passing ( 4 – 2 ). shift engagements of the vehicle are also evaluated, as in park to reverse, etc. durability / corrosion engineering : durability and corrosion engineering is the evaluation testing of a vehicle for its useful life. tests include mileage accumulation, severe driving conditions, and corrosive salt baths. drivability : drivability is the vehicle ' s response to general driving conditions. cold starts and stalls, rpm dips, idle response, launch hesitations and stumbles, and performance levels all contribute to the overall drivability of any given vehicle. cost : the cost of a vehicle program is typically split into the effect | https://en.wikipedia.org/wiki/Automotive_engineering |
pyrite, also known as fool ' s gold is the thermodynamic stable polymorph of fes $ _ 2 $. it is widely considered as a promising d - band semiconductor for various applications due to its intriguing physical properties. marcasite is the other naturally occurring polymorph of fes $ _ 2 $. measurements on natural crystals have shown that it has similarly promising electronic, mechanical, and optical properties as pyrite. however, it has been only scarcely investigated so far, because the laboratory - based synthesis of phase - pure samples or high - quality marcasite single crystal has been a challenge until now. here, we report the targeted phase formation via hydrothermal synthesis of marcasite and pyrite. the formation condition and phase purity of the fes $ _ 2 $ polymorphs are systematically studied in the form of a comprehensive synthesis map. we, furthermore, report on a detailed analysis of marcasite single crystal growth by a space - separated hydrothermal synthesis. we observe that single phase product of marcasite forms only on the surface under the involvement of h $ _ 2 $ s and sulphur vapor. the availability of high - quality crystals of marcasite allows us to measure the fundamental physical properties, including an allowed direct optical bandgap of 0. 76 ev, temperature independent diamagnetism, an electronic transport gap of 0. 11 ev, and a room - temperature carrier concentration of 4. 14 $ \ times $ 10 $ ^ { 18 } $ cm $ ^ { - 3 } $. x - ray absorption / emission spectroscopy are employed to measure the band gap of the two fes $ _ 2 $ phases. we find marcasite has a band gap of 0. 73 ev, while pyrite has a band gap of 0. 87 ev. our results indicate that marcasite - - that is now synthetically available in a straightforward fashion - - is as equally promising as pyrite as candidate for various semiconductor applications based on earth abundant elements. | arxiv:2111.12440 |
we demonstrate a compact all - fiber polarization - independent up - conversion single - photon detector based on integrated reverse proton exchanged periodically poled lithium niobate waveguides. the horizontally and vertically polarized components of randomly polarized signals are separated with a fiber - coupled polarization beam splitter, launched into two orthogonally polarized polarization maintaining fibers and fetched into two adjacent independent waveguides on the same device. the up - converted outputs from both waveguide channels are then combined with a multi - mode fiber combiner and detected by a silicon detector. with this configuration, the polarization - independent single - photon counting at 1. 55 um is achieved with a system detection efficiency of 29. 3 %, a dark count rate of 1600 counts per second, and a polarization dependent loss of 0. 1db. this compact all - fiber system is robust and has great application potential in practical quantum key distribution systems. | arxiv:1903.05814 |
in this communication we present a generalization of the donnachie - landshoff model inspired by the recent discovery of a 2 - component pomeron in lla - qcd by bartels, lipatov and vacca. in particular, we explore a new property, not present in the usual regge theory - the g - universality - which signifies the independence of one of the pomeron components on the nature of the initial and final hadrons. the best description of all the forward hadron - hadron, gamma - gamma and gamma - proton data is obtained when g - universailty is imposed. moreover, the maximal ( ln ) * * 2 behaviour of the hadron amplitude, first established by heisenberg, is clearly favoured by the data. | arxiv:hep-ph/0010292 |
we extend forester ' s rigidity theorem so as to give a complete characterization of rigid group actions on trees ( an action is rigid if it is the only reduced action in its deformation space, in particular it is invariant under automorphisms preserving the set of elliptic subgroups ). | arxiv:math/0409245 |
the hamiltonian formulation with action - angle variables is very useful when considering the motion of particles undergoing a self - force reaction due to gravitational wave emission. using the proper time as a parameter along the trajectory is considered to be appropriate when developing formal arguments, but these arguments can easily be extended to arguments with other time variables. the aim of this paper is to clarify the relations between the schemes with various parameterizations of the orbit. | arxiv:2410.22858 |
the purpose of this reanalysis of the wmap uncalibrated time ordered data ( tod ) was two fold. the first was to reassess the reliability of the detection of the anisotropies in the official wmap sky maps of the cosmic microwave background ( cmb ). the second was to assess the performance of a proposed criterion in avoiding systematic error in detecting a signal of interest. the criterion was implemented by testing the null hypothesis that the uncalibrated tod was consistent with no anisotropies when wmap ' s hourly calibration parameters were allowed to vary. it was shown independently for all 20 wmap channels that sky maps with no anisotropies were a better fit to the tod than those from the official analysis. the recently launched planck satellite should help sort out this perplexing result. | arxiv:0905.3971 |
we describe infinitesimally dirac groupoids via geometric objects that we call dirac bialgebroids. in the two well - understood special cases of poisson and presymplectic groupoids, the dirac bialgebroids are equivalent to the lie bialgebroids and im - $ 2 $ - forms, respectively. in the case of multiplicative involutive distributions on lie groupoids, we find new properties of infinitesimal ideal systems. | arxiv:1403.2934 |
we measure the pressure dependence of the electrical resistivity and the crystal structure of iron superconductor sr2vo3feas. below ~ 10 gpa the structure compresses but remains undeformed, with regular feas4 tetrahedrons, and a constant tc. beyond 10gpa, the tetrahedron strongly distorts, while tc goes gradually to zero. band structure calculations of the undistorted structure show multiple nesting features that hinder the development of an antiferromagnetic ground state ( af ), allowing the appearance of superconductivity. the deformation of the tetrahedra that breaks band degeneracy degrades multiple nesting, thus favouring one particular af state at the expense of tc. | arxiv:1110.1559 |
properties of the additive differential probability $ \ mathrm { adp } ^ { \ mathrm { xr } } $ of the composition of bitwise xor and a bit rotation are investigated, where the differences are expressed using addition modulo $ 2 ^ n $. this composition is widely used in arx constructions consisting of additions modulo $ 2 ^ n $, bit rotations and bitwise xors. differential cryptanalysis of such primitives may involve maximums of $ \ mathrm { adp } ^ { \ mathrm { xr } } $, where some of its input or output differences are fixed. although there is an efficient way to calculate this probability ( velichkov et al, 2011 ), many of its properties are still unknown. in this work, we find maximums of $ \ mathrm { adp } ^ { \ mathrm { xr } } $, where the rotation is one bit left / right and one of its input differences is fixed. some symmetries of $ \ mathrm { adp } ^ { \ mathrm { xr } } $ are obtained as well. we provide all its impossible differentials in terms of regular expression patterns and estimate the number of them. this number turns out to be maximal for the one bit left rotation and noticeably less than the number of impossible differentials of bitwise xor. | arxiv:2303.04097 |
pneumothorax, a collapsed or dropped lung, is a fatal condition typically detected on a chest x - ray by an experienced radiologist. due to shortage of such experts, automated detection systems based on deep neural networks have been developed. nevertheless, applying such systems in practice remains a challenge. these systems, mostly compute a single probability as output, may not be enough for diagnosis. on the contrary, content - based medical image retrieval ( cbir ) systems, such as image search, can assist clinicians for diagnostic purposes by enabling them to compare the case they are examining with previous ( already diagnosed ) cases. however, there is a lack of study on such attempt. in this study, we explored the use of image search to classify pneumothorax among chest x - ray images. all chest x - ray images were first tagged with deep pretrained features, which were obtained from existing deep learning models. given a query chest x - ray image, the majority voting of the top k retrieved images was then used as a classifier, in which similar cases in the archive of past cases are provided besides the probability output. in our experiments, 551, 383 chest x - ray images were obtained from three large recently released public datasets. using 10 - fold cross - validation, it is shown that image search on deep pretrained features achieved promising results compared to those obtained by traditional classifiers trained on the same features. to the best of knowledge, it is the first study to demonstrate that deep pretrained features can be used for cbir of pneumothorax in half a million chest x - ray images. | arxiv:2007.15429 |
the neutron capture cross sections and average radiative widths of neutron resonances for two double - magic nuclei 132sn and 208pb have been calculated using the microscopic photon strength functions, which were obtained within the microscopic self - consistent version of the extended theory of finite fermi systems in the time blocking approximation. for the first time, the microscopic psfs have been obtained within the fully self - consistent approach with exact accounting for the single particle continuum ( for 208pb ). the approach includes phonon coupling effects in addition to the standard rpa approach. the known skyrme force has been used. the calculations of nuclear reaction characteristics have been performed with the empire 3. 1 nuclear reaction code. here, three nuclear level density ( nld ) models have been used : the so - called phenomenological gsm, the empire specific ( or enhanced gsm ) and the microscopical combinatorial hfb nld models. for both considered characteristics we found a significant disagreement between the results obtained with the gsm and hfb nld models. for 208pb, a reasonable agreement has been found with systematics for the average radiative widths values with hfb nld and with the experimental data for the hfb nld average resonance spacing d0, while for these two quantities the differences between the values obtained with gsm and hfb nld are of several orders of magnitude. the discrepancies between the results with the phenomenological eglo psf and microscopic rpa or tba are much less for the same nld model. | arxiv:1509.07701 |
this paper gives a simple example of a family of calabi - yaus of any dimension with canonical singularities of dimension one, whose kuranishi space is singular. thus the bogomolov - tian - todorov unobstructedness theorem is not true for calabi - yaus with canonical singularities. | arxiv:alg-geom/9402014 |
we propose a simple explanation for the increase of approximately 3 mev / c ^ 2 in the mass value of the x ( 3872 ) obtained from d ^ { * 0 } { d ^ 0 } bar decay relative to that obtained from decay to j / psi pi + pi -. if the total width of the x ( 3872 ) is 2 - 3 mev, the peak position in the d ^ { * 0 } { d ^ 0 } bar invariant mass distribution is sensitive to the final state orbital angular momentum because of the proximity of the x ( 3872 ) to d ^ { * 0 } { d ^ 0 } bar threshold. we show that for total width 3 mev and one unit of orbital angular momentum, a mass shift ~ 3 mev / c ^ 2 is obtained ; experimental mass resolution should slightly increase this value. a consequence is that spin - parity 2 ^ - is favored for the x ( 3872 ). | arxiv:0710.5191 |
compelling evidence has been given for the high energy efficiency and update rates of neuromorphic processors, with performance beyond what standard von neumann architectures can achieve. such promising features could be advantageous in critical embedded systems, especially in robotics. to date, the constraints inherent in robots ( e. g., size and weight, battery autonomy, available sensors, computing resources, processing time, etc. ), and particularly in aerial vehicles, severely hamper the performance of fully - autonomous on - board control, including sensor processing and state estimation. in this work, we propose a spiking neural network ( snn ) capable of estimating the pitch and roll angles of a quadrotor in highly dynamic movements from 6 - degree of freedom inertial measurement unit ( imu ) data. with only 150 neurons and a limited training dataset obtained using a quadrotor in a real world setup, the network shows competitive results as compared to state - of - the - art, non - neuromorphic attitude estimators. the proposed architecture was successfully tested on the loihi neuromorphic processor on - board a quadrotor to estimate the attitude when flying. our results show the robustness of neuromorphic attitude estimation and pave the way towards energy - efficient, fully autonomous control of quadrotors with dedicated neuromorphic computing systems. | arxiv:2304.08802 |
recent studies invoke the superiority of the multivariate total correlation concept over the conventional pairwise measures of functional connectivity in biological networks. those seminal works certainly show that empirical measures of total correlation lead to connectivity patterns that differ from what is obtained using the most popular measure, linear correlation, or its higher order and nonlinear alternative mutual information. however, they do not provide analytical results that explain the differences beyond the obvious multivariate versus bivariate definitions. moreover, the accuracy of the empirical estimators could not be addressed directly because no controlled scenario with known analytical result was provided either. this point is critical because empirical estimation of information theory measures is always challenging. as opposed to previous empirical approaches, in this work we present analytical results to prove the advantages of total correlation over mutual information to describe the functional connectivity. in particular, we do it in neural networks for early vision ( retina - lgn - cortex ) which are realistic but simple enough to get analytical results. the presented analytical setting is also useful to check empirical estimates of total correlation. therefore, once certain estimate can be trusted, one can explore the behavior with natural signals where the analytical results ( that assume gaussian signals ), may not be valid. in this regard, as applications ( a ) we explore the effect of connectivity and feedback in the analytical retina - lgn - cortex network with natural images, and ( b ) we assess the functional connectivity in visual areas v1 - v2 - v3 - v4 from actual fmri recordings. | arxiv:2208.05770 |
a method for determining the positions of hologram dislocations relative to the optical axes of entangled laguerre gaussian modes is proposed. in our method, the coincidence count rate distribution was obtained by scanning the position of one of the holograms in two dimensions. then, the relative position of the hologram dislocation was determined quantitatively from the positions of the minimum and maximum coincidence count rates. the validity of the method was experimentally verified, and in addition, an experiment demonstrating the violation of the clauser - horne - shimony - holt inequality was performed using the well - identified optical axes of the entangled modes. | arxiv:quant-ph/0602199 |
we develop a self - consistent maxwell - bloch formalism for the interaction of x - rays with two - dimensional crystalline materials by incorporating the bloch theorem and coulomb many - body interaction. this formalism is illustrated for graphene, by calculating the polarization - dependent xanes, formulating expressions for the radiative and meinter - auger recombination of core - holes, and the discussion of microscopic insights into the spectral oscillations of exafs beyond point scattering theory. in particular, the correct inclusion of lattice periodicity in our evaluation allows us to assign so far uninterpreted spectral features in the fourier transformed exafs spectrum. | arxiv:2212.04727 |
we study the regularity of the lyapunov exponent for quasi - periodic cocycles $ ( t _ \ omega, a ) $ where $ t _ \ omega $ is an irrational rotation $ x \ to x + 2 \ pi \ omega $ on $ \ ss ^ 1 $ and $ a \ in { \ cal c } ^ l ( \ ss ^ 1, sl ( 2, \ mathbb { r } ) ) $, $ 0 \ le l \ le \ infty $. for any fixed $ l = 0, 1, 2, \ cdots, \ infty $ and any fixed $ \ omega $ of bounded - type, we construct $ d _ { l } \ in { \ cal c } ^ l ( \ ss ^ 1, sl ( 2, \ mathbb { r } ) ) $ such that the lyapunov exponent is not continuous at $ d _ { l } $ in $ { \ cal c } ^ l $ - topology. we also construct such examples in a smaller schr \ " odinger class. | arxiv:1202.0580 |
machine learning enables systems to build and update domain models based on runtime observations. in this paper, we study statistical model checking and runtime verification for systems with this ability. two challenges arise : ( 1 ) models built from limited runtime data yield uncertainty to be dealt with. ( 2 ) there is no definition of satisfaction w. r. t. uncertain hypotheses. we propose such a definition of subjective satisfaction based on recently introduced satisfaction functions. we also propose the bv algorithm as a bayesian solution to runtime verification of subjective satisfaction under model uncertainty. bv provides user - definable stochastic bounds for type i and ii errors. we discuss empirical results from an example application to illustrate our ideas. | arxiv:1702.08725 |
we extend the positivity - preserving method of zhang & shu ( 2010, jcp, 229, 3091 - 3120 ) to simulate the advection of neutral particles in phase space using curvilinear coordinates. the ability to utilize these coordinates is important for non - equilibrium transport problems in general relativity and also in science and engineering applications with specific geometries. the method achieves high - order accuracy using discontinuous galerkin ( dg ) discretization of phase space and strong stability - preserving, runge - kutta ( ssp - rk ) time integration. special care in taken to ensure that the method preserves strict bounds for the phase space distribution function $ f $ ; i. e., $ f \ in [ 0, 1 ] $. the combination of suitable cfl conditions and the use of the high - order limiter proposed in zhang & shu ( 2010 ) is sufficient to ensure positivity of the distribution function. however, to ensure that the distribution function satisfies the upper bound, the discretization must, in addition, preserve the divergence - free property of the phase space flow. proofs that highlight the necessary conditions are presented for general curvilinear coordinates, and the details of these conditions are worked out for some commonly used coordinate systems ( i. e., spherical polar spatial coordinates in spherical symmetry and cylindrical spatial coordinates in axial symmetry, both with spherical momentum coordinates ). results from numerical experiments - - - including one example in spherical symmetry adopting the schwarzschild metric - - - demonstrate that the method achieves high - order accuracy and that the distribution function satisfies the maximum principle. | arxiv:1410.7431 |
the physics that governs quantum monitoring may involve other degrees of freedom than the ones initialised and controlled for probing. in this context we address the simultaneous estimation of phase and dephasing characterizing a dispersive medium, and we explore the role of frequency correlations within a photon pair generated via parametric down - conversion, when used as a probe for the medium. we derive the ultimate quantum limits on the estimation of the two parameters, by calculating the corresponding quantum cram \ ' er - rao bound ; we then consider a feasible estimation scheme, based on the measurement of stokes operators, and address its absolute performances in terms of the correlation parameters, and, more fundamentally, of the role played by correlations in the simultaneous achievability of the quantum cram \ ' er - rao bounds for each of the two parameters. | arxiv:1712.06860 |
we report a spectroscopic search for hypervelocity white dwarfs ( wds ) that are runaways from type ia supernovae ( sne ia ) and related thermonuclear explosions. candidates are selected from gaia data with high tangential velocities and blue colors. we find six new runaways, including four stars with radial velocities ( rvs ) $ > 1000 \, \ rm km \, s ^ { - 1 } $ and total space velocities $ \ gtrsim 1300 \, \ rm km \, s ^ { - 1 } $. these are most likely the surviving donors from double - degenerate binaries in which the other wd exploded. the other two objects have lower minimum velocities, $ \ gtrsim 600 \, \ rm km \, s ^ { - 1 } $, and may have formed through a different mechanism, such as pure deflagration of a wd in a type iax supernova. the four fastest stars are hotter and smaller than the previously known " d $ ^ 6 $ stars, " with effective temperatures ranging from $ \ sim $ 20, 000 to $ \ sim $ 130, 000 k and radii of $ \ sim 0. 02 - 0. 10 \, r _ { \ odot } $. three of these have carbon - dominated atmospheres, and one has a helium - dominated atmosphere. two stars have rvs of $ - 1694 $ and $ - 2285 \ rm \, km \, s ^ { - 1 } $ - - the fastest systemic stellar rvs ever measured. their inferred birth velocities, $ \ sim 2200 - 2500 \, \ rm km \, s ^ { - 1 } $, imply that both wds in the progenitor binary had masses $ > 1. 0 \, m _ { \ odot } $. the high observed velocities suggest that a dominant fraction of the observed hypervelocity wd population comes from double - degenerate binaries whose total mass significantly exceeds the chandrasekhar limit. however, the two nearest and faintest d $ ^ 6 $ stars have the lowest velocities and masses, suggesting that observational selection effects favor rarer, higher - mass stars. a significant population of fainter low - mass runaways may still await discovery. we infer a birth rate of d $ ^ 6 $ stars that is consistent | arxiv:2306.03914 |
we investigate the ground - state properties and the collective modes of a two - dimensional two - component rydberg - dressed fermi liquid in the dipole - blockade regime. we find instability of the homogeneous system toward phase separated and density ordered phases, using the hartree - fock and random - phase approximations, respectively. the spectral weight of collective density oscillations in the homogenous phase also signals the emergence of density - wave instability. we examine the effect of exchange - hole on the density - wave instability and on the collective mode dispersion using the hubbard local - field factor. | arxiv:1706.03222 |
we present the transverse flux correlation function of the lyman - alpha forest in quasar absorption spectra at z ~ 2. 1 from vlt - fors and vlt - uves observations of a total of 32 pairs of quasars ; 26 pairs with separations in the range 0. 6 < theta < 4 arcmin and 6 pairs with 4 < theta < 10 arcmin. correlation is detected at the 3sigma level up to separations of the order of ~ 4 arcmin ( or ~ 4. 4 h ^ { - 1 } mpc comoving at z = 2. 1 for omega _ { m } = 0. 3 and omega _ { lambda } = 0. 7 ). we have, furthermore, measured the longitudinal correlation function at a somewhat higher mean redshift ( z = 2. 39 ) from 20 lines of sight observed with high spectral resolution and high signal - to - noise ratio with vlt - uves. we compare the observed transverse and longitudinal correlation functions to that obtained from numerical simulations and illustrate the effect of spectral resolution, thermal broadening and peculiar motions. the shape and correlation length of the correlation functions are in good agreement with those expected from absorption by the filamentary and sheet - like structures in the photoionized warm intergalactic medium predicted in cdm - like models for structures formation. using a sample of 139 c _ { iv } systems detected along the lines of sight toward the pairs of quasars we also investigate the transverse correlation of metals on the same scales. the observed transverse correlation function of intervening c _ { iv } absorption systems is consistent with that of a randomly distributed population of absorbers. this is likely due to the small number of pairs with separation less than 2 arcmin. we detect, however, a significant overdensity of systems in the sightlines towards the quartet q0103 - 294a & b, q0102 - 2931 and q0102 - 293 which extends over the redshift range 1. 5 < z < 2. 2 and an angular scale larger than 10 arcmin. | arxiv:astro-ph/0605618 |
problems in the field of open quantum systems often involve an environment that strongly influences the dynamics of excited states. here we present a numerical method to model optical spectra of non - markovian open quantum systems. the method employs a process tensor framework to efficiently compute multi - time correlations in a numerically exact way. to demonstrate the efficacy of our method, we compare 2d electronic spectroscopy simulations produced through our method to markovian master equation simulations in three different system - bath coupling regimes. | arxiv:2402.15454 |
using an effective theory for an ensemble of center vortices, we observe the area law fall - off in the continuum limit for the su ( $ 2 $ ) gauge group in three - dimensional euclidean space - time. the string tension is obtained in terms of the intrinsic properties of the vortices and the parameter describing their interactions. a good qualitative agreement between our results and the lattice ones is observed. in addition, we show that the repulsive force between the vortices increases with temperature. this behavior is expected due to the reduction of vortex configuration at higher temperatures, required for the deconfinement regime. | arxiv:2312.03660 |
multimodal contrastive learning has emerged as a powerful paradigm for building high - quality features using the complementary strengths of various data modalities. however, the open nature of such systems inadvertently increases the possibility of backdoor attacks. these attacks subtly embed malicious behaviors within the model during training, which can be activated by specific triggers in the inference phase, posing significant security risks. despite existing countermeasures through fine - tuning that reduce the adverse impacts of such attacks, these defenses often degrade the clean accuracy and necessitate the construction of extensive clean training pairs. in this paper, we explore the possibility of a less - cost defense from the perspective of model unlearning, that is, whether the model can be made to quickly \ textbf { u } nlearn \ textbf { b } ackdoor \ textbf { t } hreats ( ubt ) by constructing a small set of poisoned samples. specifically, we strengthen the backdoor shortcuts to discover suspicious samples through overfitting training prioritized by weak similarity samples. building on the initial identification of suspicious samples, we introduce an innovative token - based localized forgetting training regime. this technique specifically targets the poisoned aspects of the model, applying a focused effort to unlearn the backdoor associations and trying not to damage the integrity of the overall model. experimental results show that our method not only ensures a minimal success rate for attacks, but also preserves the model ' s high clean accuracy. | arxiv:2403.16257 |
evaluating distance to collision for robot manipulators is useful for assessing the feasibility of a robot configuration or for defining safe robot motion in unpredictable environments. however, distance estimation is a timeconsuming operation, and the sensors involved in measuring the distance are always noisy. a challenge thus exists in evaluating the expected distance to collision for safer robot control and planning. in this work, we propose the use of gaussian process ( gp ) regression and the forward kinematics ( fk ) kernel ( a similarity function for robot manipulators ) to efficiently and accurately estimate distance to collision. we show that the gp model with the fk kernel achieves 70 times faster distance evaluations compared to a standard geometric technique, and up to 13 times more accurate evaluations compared to other regression models, even when the gp is trained on noisy distance measurements. we employ this technique in trajectory optimization tasks and observe 9 times faster optimization than with the noise - free geometric approach yet obtain similar optimized motion plans. we also propose a confidence - based hybrid model that uses model - based predictions in regions of high confidence and switches to a more expensive sensor - based approach in other areas, and we demonstrate the usefulness of this hybrid model in an application involving reaching into a narrow passage. | arxiv:2005.14391 |
let $ \ frak t _ 2 $ ( resp. $ \ mathfrak { t } $ ) be the hermitian symmetric domain of $ spin ( 2, 10 ) $ ( resp. $ e _ { 7, 3 } $ ). in the previous work, we constructed holomorphic cusp forms on $ \ mathfrak { t } $ from elliptic cusp forms with respect to $ sl _ 2 ( \ mathbb { z } ) $. by using such cusp forms we construct holomorphic cusp forms on $ \ mathfrak { t } _ 2 $ which are similar to miyawaki lift in symplectic groups established by t. ikeda. | arxiv:1509.00523 |
we investigate the integration of word embeddings as classification features in the setting of large scale text classification. such representations have been used in a plethora of tasks, however their application in classification scenarios with thousands of classes has not been extensively researched, partially due to hardware limitations. in this work, we examine efficient composition functions to obtain document - level from word - level embeddings and we subsequently investigate their combination with the traditional one - hot - encoding representations. by presenting empirical evidence on large, multi - class, multi - label classification problems, we demonstrate the efficiency and the performance benefits of this combination. | arxiv:1606.06623 |
when a liquid is cooled below its melting temperature, if crystallization is avoided, it forms a glass. this phenomenon, called glass transition, is characterized by a marked increase of viscosity, about 14 orders of magnitude, in a narrow temperature interval. the microscopic mechanism behind the glass transition is still poorly understood. however, recently, great advances have been made in the identification of cooperative rearranging regions, or dynamical heterogeneities, i. e. domains of the liquid whose relaxation is highly correlated. the growth of the size of these domains is now believed to be the driving mechanism for the increase of the viscosity. recently a tool to quantify the size of these domains has been proposed. we apply this tool to a wide class of materials to investigate the correlation between the size of the heterogeneities and their configurational entropy, i. e. the number of states accessible to a correlated domain. we find that the relaxation time of a given system, apart from a material dependent pre - factor, is a universal function of the configurational entropy of a correlated domain. as a consequence, we find that at the glass transition temperature, the size of the domains and the configurational entropy per unit volume are anti - correlated, as originally predicted by the adam - gibbs theory. finally, we use our data to extract some exponents defined in the framework of the random first order theory, a recent quantitative theory of the glass transition. | arxiv:0710.1249 |
starting from the full - - shift on a finite alphabet $ a $, mingling some symbols of $ a $, we obtain a new full shift on a smaller alphabet $ b $. this amalgamation defines a factor map from $ ( a ^ { \ mathbb n }, t _ a ) $ to $ ( b ^ { \ mathbb n }, t _ b ) $, where $ t _ a $ and $ t _ b $ are the respective shift maps. according to the thermodynamic formalism, to each regular function ( ` potential ' ) $ \ psi : a ^ { \ mathbb n } \ to { \ mathbb r } $, we can associate a unique gibbs measure $ \ mu _ \ psi $. in this article, we prove that, for a large class of potentials, the pushforward measure $ \ mu _ \ psi \ circ \ pi ^ { - 1 } $ is still gibbsian for a potential $ \ phi : b ^ { \ mathbb n } \ to { \ mathbb r } $ having a ` bit less ' regularity than $ \ psi $. in the special case where $ \ psi $ is a ` 2 - - symbol ' potential, the gibbs measure $ \ mu _ \ psi $ is nothing but a markov measure and the amalgamation $ \ pi $ defines a hidden markov chain. in this particular case, our theorem can be recast by saying that a hidden markov chain is a gibbs measure ( for a h \ " older potential ). | arxiv:0907.0528 |
we present the results of modelling the subgiant star $ \ beta $ hydri using the seismic observational constraints. we have computed several grids of stellar evolutionary tracks using aarhus stellar evolution code ( astec, christensen - dalsgaard, 2008a ), with and without helium diffusion and settling. for those models on each track that are located at the observationally determined position of $ \ beta $ hydri in the hr diagram, we have calculated the oscillation frequencies using aarhus adiabatic pulsation package ( adipls, christensen - dalsgaard, 2008b ). applying the near - surface corrections to the calculated frequencies using the empirical law presented by kjeldsen et al. ( 2008 ), we have compared the corrected model frequencies with the observed frequencies of the star. we show that after correcting the frequencies for the near - surface effects, we have a fairly good fit for both $ l $ = 0 and $ l $ = 2 frequencies. we also have good agreement between the observed and calculated $ l $ = 1 mode frequencies although there is room for improvement in order to fit all the observed mixed modes simultaneously. | arxiv:0912.3653 |
we describe a groebner basis of relations among conditional probabilities in a discrete probability space, with any set of conditioned - upon events. they may be specialized to the partially - observed random variable case, the purely conditional case, and other special cases. we also investigate the connection to generalized permutohedra and describe a conditional probability simplex. | arxiv:0808.1149 |
by considering a limiting form of the q - dixon _ 4 \ phi _ 3 summation, we prove a weighted partition theorem involving odd parts differing by > = 4. a two parameter refinement of this theorem is then deduced from a quartic reformulation of goellnitz ' s ( big ) theorem due to alladi, and this leads to a two parameter extension of jacobi ' s triple product identity for theta functions. finally, refinements of certain modular identities of alladi connected to the goellnitz - gordon series are shown to follow from a limiting form of the q - dixon _ 4 \ phi _ 3 summation. | arxiv:math/0205031 |
several of the many proposed dark matter candidate particles, already investigated with lower exposure and a higher software energy threshold, are further analyzed including the first dama / libra - - phase2 data release, with an exposure of 1. 13 ton $ \ times $ yr and a lower software energy threshold ( 1 kev ). the cumulative exposure above 2 kev considering also dama / nai and dama / libra - - phase1 results is now 2. 46 ton $ \ times $ yr. the analysis permits to constraint the parameters ' space of the considered candidates restricting their values - - with respect to previous analyses - - thanks to the increase of the exposure and to the lower energy threshold. | arxiv:1907.06405 |
the bershadsky - polyakov algebra is the $ \ mathcal { w } $ - algebra associated to $ \ mathfrak { s } \ mathfrak { l } _ 3 $ with its minimal nilpotent element $ f _ { \ theta } $. for notational convenience we define $ \ mathcal { w } ^ { \ ell } = \ mathcal { w } ^ { \ ell - 3 / 2 } ( \ mathfrak { s } \ mathfrak { l } _ 3, f _ { \ theta } ) $. the simple quotient of $ \ mathcal { w } ^ { \ ell } $ is denoted by $ \ mathcal { w } _ { \ ell } $, and for $ \ ell $ a positive integer, $ \ mathcal { w } _ { \ ell } $ is known to be $ c _ 2 $ - cofinite and rational. we prove that for all positive integers $ \ ell $, $ \ mathcal { w } _ { \ ell } $ contains a rank one lattice vertex algebra $ v _ l $, and that the coset $ \ mathcal { c } _ { \ ell } = \ text { com } ( v _ l, \ mathcal { w } _ { \ ell } ) $ is isomorphic to the principal, rational $ \ mathcal { w } ( \ mathfrak { s } \ mathfrak { l } _ { 2 \ ell } ) $ - algebra at level $ ( 2 \ ell + 3 ) / ( 2 \ ell + 1 ) - 2 \ ell $. this was conjectured in the physics literature over 20 years ago. as a byproduct, we construct a new family of rational, $ c _ 2 $ - cofinite vertex superalgebras from $ \ mathcal { w } _ { \ ell } $ | arxiv:1511.09143 |
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