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we study the problem of finding optimal correlated equilibria of various sorts in extensive - form games : normal - form coarse correlated equilibrium ( nfcce ), extensive - form coarse correlated equilibrium ( efcce ), and extensive - form correlated equilibrium ( efce ). we make two primary contributions. first, we introduce a new algorithm for computing optimal equilibria in all three notions. its runtime depends exponentially only on a parameter related to the information structure of the game. we also prove a fundamental complexity gap : while our size bounds for nfcce are similar to those achieved in the case of team games by zhang et al., this is impossible to achieve for the other two concepts under standard complexity assumptions. second, we propose a two - sided column generation approach for use when the runtime or memory usage of the previous algorithm is prohibitive. our algorithm improves upon the one - sided approach of farina et al. by means of a new decomposition of correlated strategies which allows players to re - optimize their sequence - form strategies with respect to correlation plans which were previously added to the support. experiments show that our techniques outperform the prior state of the art for computing optimal general - sum correlated equilibria. | arxiv:2203.07181 |
we study distributions of random vectors whose components are second order polynomials in gaussian random variables. assuming that the law of such a vector is not absolutely continuous with respect to lebesgue measure, we derive some interesting consequences. our second result gives a characterization of limits in law for sequences of such vectors. | arxiv:1305.5990 |
we propose a scheme for quantum key distribution ( qkd ) in a passive optical network ( pon ) based on differential phase shift ( dps ) coding. a centralized station including all expensive components serves many users, making it suitable for a true multi - user network in a local environment with moderate distances on the order of a few kilometers. the emphasis lies on an asymmetric design for cost effective implementation of network end points. | arxiv:1412.6311 |
there is a growing trend of teaching large language models ( llms ) to solve mathematical problems through coding. existing studies primarily focus on prompting powerful, closed - source models to generate seed training data followed by in - domain data augmentation, equipping llms with considerable capabilities for code - aided mathematical reasoning. however, continually training these models on augmented data derived from a few datasets such as gsm8k may impair their generalization abilities and restrict their effectiveness to a narrow range of question types. conversely, the potential of improving such llms by leveraging large - scale, expert - written, diverse math question - answer pairs remains unexplored. to utilize these resources and tackle unique challenges such as code response assessment, we propose a novel paradigm that uses a code - based critic model to guide steps including question - code data construction, quality control, and complementary evaluation. we also explore different alignment algorithms with self - generated instruction / preference data to foster continuous improvement. experiments across both in - domain ( up to + 5. 7 % ) and out - of - domain ( + 4. 4 % ) benchmarks in english and chinese demonstrate the effectiveness of the proposed paradigm. | arxiv:2408.15565 |
we study the localization properties of non - interacting waves propagating in a speckle - like potential superposed on a one - dimensional lattice. using a decimation / renormalization procedure, we estimate the localization length for a tight - binding hamiltonian where site - energies are square - sinc - correlated random variables. by decreasing the width of the correlation function, the disorder patterns approaches a $ \ delta $ - correlated disorder, and the localization length becomes almost energy - independent in the strong disorder limit. we show that this regime can be reached for a size of the speckle grains of the order of ( lower than ) four lattice steps. | arxiv:1110.2287 |
we discuss the case of simultaneous mixing of gauge bosons and mixing of fermions in a model independent way and for a variety of extra - fermion representations. in this context we analyze a class of lepton family violating processes, namely z - - > e tau, z - - > mu tau, z - - > e mu, mu - - > e e e, tau - - > e e e, tau - - > mu mu mu, tau - - > e mu mu and tau - - > mu e e in the presence of one extra neutral gauge boson, z ', with universal, non - universal or family changing couplings. we derive bounds on the combined effect of z - z ' mixing and ordinary - - exotic lepton mixing. | arxiv:hep-ph/9611442 |
electrocardiogram ( ecg ) is one of the most convenient and non - invasive tools for monitoring peoples ' heart condition, which can use for diagnosing a wide range of heart diseases, including cardiac arrhythmia, acute coronary syndrome, et al. however, traditional ecg disease detection models show substantial rates of misdiagnosis due to the limitations of the abilities of extracted features. recent deep learning methods have shown significant advantages, but they do not provide publicly available services for those who have no training data or computational resources. in this paper, we demonstrate our work on building, training, and serving such out - of - the - box cloud deep learning service for cardiac disease detection from ecg named cardiolearn. the analytic ability of any other ecg recording devices can be enhanced by connecting to the internet and invoke our open api. as a practical example, we also design a portable smart hardware device along with an interactive mobile program, which can collect ecg and detect potential cardiac diseases anytime and anywhere. | arxiv:2007.02165 |
we perform a comparative study of the time dependence of the holographic quantum complexity of some space like singular bulk gravitational backgrounds. this is done by considering the two available notions of complexity, one that relates it to the maximal spatial volume and the other that relates it to the classical action of the wheeler - de witt patch. we calculate and compare the leading and the next to leading terms and find some universal features. the complexity decreases towards the singularity for both definitions, for all types of singularities studied. in addition the leading terms have the same quantitative behavior for both definitions in restricted number of cases and the behaviour itself is different for different singular backgrounds. the quantitative details of the next to leading terms, such as their specific form of time dependence, are found not to be universal. they vary between the different cases and between the different bulk definitions of complexity. we also address some technical points inherent to the calculation. | arxiv:1802.02045 |
recently, a novel type of a multiscale simulation, called relative resolution ( relres ), was introduced. in a single system, molecules switch their resolution in terms of their relative separation, with near neighbors interacting via fine - grained potentials yet far neighbors interacting via coarse - grained potentials ; notably, these two potentials are analytically parameterized by a multipole approximation. this multiscale approach is consequently able to correctly retrieve across state space, the structural and thermal, as well as static and dynamic, behavior of various nonpolar mixtures. our current work focuses on the practical implementation of relres in lammps, specifically for the commonly used lennard - jones potential. by examining various correlations and properties of several alkane liquids, including complex solutions of alternate cooligomers and block copolymers, we confirm the validity of this automated lammps algorithm. most importantly, we demonstrate that this relres implementation gains almost an order of magnitude in computational efficiency, as compared with conventional simulations. we thus recommend this novel lammps algorithm for anyone studying systems governed by lennard - jones interactions. | arxiv:2104.10231 |
the use of supernovae of type ia for the determination of accurate distances rests upon the empirical phillips relation, in which the brightest events are the broadest in time. implications of new data upon the homogeneity of light curves under the operation of a stretch in time, of the parabolic luminosity increase at the earliest times, and of the time from explosion to maximum light are discussed. the early luminosity is in excellent agreement with predictions ( arnett 1982 ), and the lack of prominent higher modes of diffusion constrain progenitor and explosion models. difficulties with reproducing the observed rise time are restricted to radiative transfer models ( e. g., hoeflich and khokhlov ), and probably due to an overestimate of thermal photon escape due to inadequate line lists. because of the strong dependence of luminosity on 56ni mass, some simple models can give a phillips relation of the correct sense. | arxiv:astro-ph/9908169 |
in this paper, we study the cooperative set tracking problem for a group of lagrangian systems. each system observes a convex set as its local target. the intersection of these local sets is the group aggregation target. we first propose a control law based on each system ' s own target sensing and information exchange with neighbors. with necessary connectivity for both cases of fixed and switching communication graphs, multiple lagrangian systems are shown to achieve rendezvous on the intersection of all the local target sets while the vectors of generalized coordinate derivatives are driven to zero. then, we introduce the collision avoidance control term into set aggregation control to ensure group dispersion. by defining an ultimate bound on the final generalized coordinate between each system and the intersection of all the local target sets, we show that multiple lagrangian systems approach a bounded region near the intersection of all the local target sets while the collision avoidance is guaranteed during the movement. in addition, the vectors of generalized coordinate derivatives of all the mechanical systems are shown to be driven to zero. simulation results are given to validate the theoretical results. | arxiv:1402.2634 |
the large abundance of electrically neutral particles has a remarkable impact on the dynamics of many astrophysical plasmas. here, we use a two - fluid model that includes charge - neutral elastic collisions and hall ' s current to study the propagation of magnetohydrodynamic ( mhd ) waves in weakly ionized plasmas. we derive the dispersion relation for small - amplitude incompressible transverse waves propagating along the background magnetic field. then, we focus on the polarization relations fulfilled by the eigenmodes and their corresponding ratios of magnetic to kinetic energies, and we study their dependence on the relations between the oscillation, collision and cyclotron frequencies. for low wave frequencies, the two components of the plasma are strongly coupled, the damping due to the charge - neutral interaction is weak and the effect of hall ' s term is negligible. however, as the wave frequency increases, phase shifts between the velocity of charges, the velocity of neutrals, and the magnetic field appear, leading to enhanced damping. the effect of collisions on the propagation of waves strongly depends on their polarization state, with the left - handed circularly polarized ion - cyclotron modes being more efficiently damped than the linearly polarized alfv \ ' en waves and the right - handed circularly polarized whistler modes. moreover, the equipartition relation between the magnetic energy and the kinetic energy of alfv \ ' en waves does not hold in general when the collisional interaction and hall ' s current are taken into account, with the magnetic energy usually dominating over the kinetic energy. this theoretical result extends previous findings from observational and numerical works about turbulence in astrophysical scenarios. | arxiv:2502.13659 |
does the training of large language models potentially infringe upon code licenses? furthermore, are there any datasets available that can be safely used for training these models without violating such licenses? in our study, we assess the current trends in the field and the importance of incorporating code into the training of large language models. additionally, we examine publicly available datasets to see whether these models can be trained on them without the risk of legal issues in the future. to accomplish this, we compiled a list of 53 large language models trained on file - level code. we then extracted their datasets and analyzed how much they overlap with a dataset we created, consisting exclusively of strong copyleft code. our analysis revealed that every dataset we examined contained license inconsistencies, despite being selected based on their associated repository licenses. we analyzed a total of 514 million code files, discovering 38 million exact duplicates present in our strong copyleft dataset. additionally, we examined 171 million file - leading comments, identifying 16 million with strong copyleft licenses and another 11 million comments that discouraged copying without explicitly mentioning a license. based on the findings of our study, which highlights the pervasive issue of license inconsistencies in large language models trained on code, our recommendation for both researchers and the community is to prioritize the development and adoption of best practices for dataset creation and management. | arxiv:2403.15230 |
in this paper we present a mixed projection - and density - based topology optimization approach. the aim is to combine the benefits of both parametrizations : the explicit geometric representation provides specific controls on certain design regions while the implicit density representation provides the ultimate design freedom elsewhere. this approach is particularly suited for structural assemblies, where the optimization of the structural topology is coupled with the optimization of the shape of the interface between the sub - components in a unified formulation. the interface between the assemblies is defined by a segmented profile made of linear geometric entities. the geometric coordinates of the nodes connecting the profile segments are used as shape variables in the problem, together with density variables as in conventional topology optimization. the variable profile is used to locally impose specific geometric constraints or to project particular material properties. examples of the properties considered herein are a local volume constraint, a local maximum length scale control, a variable young ' s modulus for the distributed solid material, and spatially variable minimum and maximum length scale. the resulting optimization approach is general and various geometric entities can be used. the potential for complex design manipulations is demonstrated through several numerical examples. | arxiv:1906.06512 |
an error analysis of runge - kutta convolution quadrature based on gauss methods applied to hyperbolic operators is given. the order of convergence relies heavily on the parity of the number of stages, a more favourable situation arising for the odd cases than the even ones. moreover, for particular situations the order of convergence is higher than for radau iia or lobatto iiic methods when using the same number of stages. we further investigate an application to transient acoustic scattering where, for certain scattering obstacles, the favourable situation occurs in the important case of the exterior dirichlet - to - neumann map. numerical experiments and comparisons show the performance of the method. | arxiv:2212.07170 |
with advances in quantum computing, researchers can now write and run many quantum programs. however, there is still a lack of effective methods for debugging quantum programs. in this paper, quantum symbolic execution ( qse ) is proposed to generate test cases, which helps to finding bugs in quantum programs. the main idea of quantum symbolic execution is to find the suitable test cases from all possible ones ( i. e. test case space ). it is different from the way of classical symbol execution, which gets test cases by calculating instead of searching. qse utilizes quantum superposition and parallelism to store the test case space with only a few qubits. according to the conditional statements in the debugged program, the test case space is continuously divided into subsets, subsubsets and so on. elements in the same subset are suitable test cases that can test the corresponding branch in the code to be tested. qse not only provides a possible way to debug quantum programs, but also avoids the difficult problem of solving constraints in classical symbolic execution. | arxiv:2209.08582 |
we revisit the invariance of the curved spacetime maxwell equations under conformal transformations. contrary to standard literature, we include the discussion of the four - current, the wave equations for the four - potential and the field, and the behaviour of gauge conditions under the conformal transformation. | arxiv:1905.09968 |
the dynamical evidence for black holes ( bhs ) in galactic nuclei is reviewed, with emphasis on recent improvements in spatial resolution, methods for analyzing galaxy spectra and dynamical modeling. m31, m32 and m87 are discussed in some detail. | arxiv:astro-ph/9410012 |
we present and analyze two algorithms for computing the hilbert class polynomial $ h _ d $. the first is a p - adic lifting algorithm for inert primes p in the order of discriminant d < 0. the second is an improved chinese remainder algorithm which uses the class group action on cm - curves over finite fields. our run time analysis gives tighter bounds for the complexity of all known algorithms for computing $ h _ d $, and we show that all methods have comparable run times. | arxiv:0802.0979 |
a novel mm - wave microstrip - fed patch antenna with broad bandwidth and wide angular coverage suitable for integration in planar arrays is designed, analyzed and verified by measurements. the antenna provides a bandwidth of 13. 1 % between 34. 1 ghz and 38. 9 ghz, which is achieved by a slotted multiple resonances microstrip patch and a matching circuit in microstrip technology. the antenna is built on ro3003 substrate with top and ground layers, which is low cost compared to other techniques. for simple integration with microstrip and frontend circuits, the feeding happens in the top layer with a microstrip coupling gap feed. the wide half power beamwidth is achieved by suitably designed parasitic patches for the first resonant mode. the second resonant mode has a wide half power beamwidth by default. the half power beamwidth is between 100 { \ deg } and 125 { \ deg } within the matched bandwidth, which is a very good value for a microstrip patch antenna radiating over a ground plane. the measured input impedance and radiation characteristic show very good agreement with simulation results. | arxiv:2105.08162 |
the design of absorbing boundary conditions ( abc ) in a numerical simulation is a challenging task. in the best cases, spurious reflections remain for some angles of incidence or at certain wave lengths. in the worst, abc are not even possible for the set of equations and / or numerical schemes used in the simulation and reflections can not be avoided at all. perflectly matched layer ( pml ) are layers of absorbing medium which can be added at the simulation edges in order to significantly damp both outgoing and reflected waves, thus effectively playing the role of an abc. they are able to absorb waves and prevent reflections for all angles and frequencies at a modest computational cost. it increases the simulation accuracy and negates the need of oversizing the simulation usually imposed by abc and leading to a waste of computational resources and power. pml for finite - difference time - domain ( fdtd ) schemes in particle - in - cell ( pic ) codes are presented for both maxwell ' s equations and, for the first time, the envelope wave equation. being of the second order, the latter requires significant evolutions with respect to the former. it applies in particular to simulations of lasers propagating in plasmas using the reduced complex envelope model. the implementation is done in the open source code smilei for both cartesian and azimuthal modes ( am ) decomposition geometries. | arxiv:2409.06287 |
topological space, such that all operations of the field ( addition, multiplication, the maps a β¦ βa and a β¦ aβ1 ) are continuous maps with respect to the topology of the space. the topology of all the fields discussed below is induced from a metric, i. e., a function d : f Γ f β r, that measures a distance between any two elements of f. the completion of f is another field in which, informally speaking, the " gaps " in the original field f are filled, if there are any. for example, any irrational number x, such as x = β2, is a " gap " in the rationals q in the sense that it is a real number that can be approximated arbitrarily closely by rational numbers p / q, in the sense that distance of x and p / q given by the absolute value | x β p / q | is as small as desired. the following table lists some examples of this construction. the fourth column shows an example of a zero sequence, i. e., a sequence whose limit ( for n β β ) is zero. the field qp is used in number theory and p - adic analysis. the algebraic closure qp carries a unique norm extending the one on qp, but is not complete. the completion of this algebraic closure, however, is algebraically closed. because of its rough analogy to the complex numbers, it is sometimes called the field of complex p - adic numbers and is denoted by cp. = = = = local fields = = = = the following topological fields are called local fields : finite extensions of qp ( local fields of characteristic zero ) finite extensions of fp ( ( t ) ), the field of laurent series over fp ( local fields of characteristic p ). these two types of local fields share some fundamental similarities. in this relation, the elements p β qp and t β fp ( ( t ) ) ( referred to as uniformizer ) correspond to each other. the first manifestation of this is at an elementary level : the elements of both fields can be expressed as power series in the uniformizer, with coefficients in fp. ( however, since the addition in qp is done using carrying, which is not the case in fp ( ( t ) ), these fields are not isomorphic. ) the following facts show that this superficial similarity goes much deeper : any first - order statement that is true for almost all qp is also true for almost all fp ( | https://en.wikipedia.org/wiki/Field_(mathematics) |
as a crucial role in cross - language information retrieval ( clir ), query translation has three main challenges : 1 ) the adequacy of translation ; 2 ) the lack of in - domain parallel training data ; and 3 ) the requisite of low latency. to this end, existing clir systems mainly exploit statistical - based machine translation ( smt ) rather than the advanced neural machine translation ( nmt ), limiting the further improvements on both translation and retrieval quality. in this paper, we investigate how to exploit neural query translation model into clir system. specifically, we propose a novel data augmentation method that extracts query translation pairs according to user clickthrough data, thus to alleviate the problem of domain - adaptation in nmt. then, we introduce an asynchronous strategy which is able to leverage the advantages of the real - time in smt and the veracity in nmt. experimental results reveal that the proposed approach yields better retrieval quality than strong baselines and can be well applied into a real - world clir system, i. e. aliexpress e - commerce search engine. readers can examine and test their cases on our website : https : / / aliexpress. com. | arxiv:2010.13659 |
for a theory with first and second class constraints, we propose a procedure for conversion of second class constraints based on deformation the structure of local symmetries of the lagrangian formulation. it does not require extension or reduction of configuration space of the theory. we give examples in which the initial formulation implies a non linear realization of some global symmetries, therefore is not convenient. the conversion reveals hidden symmetry presented in the theory. the extra gauge freedom of conversed version is used to search for a parameterization which linearizes the equations of motion. we apply the above procedure to membrane theory ( in the formulation with world - volume metric ). in the resulting version, all the metric components are gauge degrees of freedom. the above procedure works also in a theory with only second class constraints presented. as an examples, we discuss arbitrary dynamical system of classical mechanics subject to kinematic constraints, o ( n ) - invariant nonlinear sigma - model, and the theory of massive vector field with maxwell - proca lagrangian. | arxiv:hep-th/0610082 |
over the past few years, online bullying and aggression have become increasingly prominent, and manifested in many different forms on social media. however, there is little work analyzing the characteristics of abusive users and what distinguishes them from typical social media users. in this paper, we start addressing this gap by analyzing tweets containing a great large amount of abusiveness. we focus on a twitter dataset revolving around the gamergate controversy, which led to many incidents of cyberbullying and cyberaggression on various gaming and social media platforms. we study the properties of the users tweeting about gamergate, the content they post, and the differences in their behavior compared to typical twitter users. we find that while their tweets are often seemingly about aggressive and hateful subjects, " gamergaters " do not exhibit common expressions of online anger, and in fact primarily differ from typical users in that their tweets are less joyful. they are also more engaged than typical twitter users, which is an indication as to how and why this controversy is still ongoing. surprisingly, we find that gamergaters are less likely to be suspended by twitter, thus we analyze their properties to identify differences from typical users and what may have led to their suspension. we perform an unsupervised machine learning analysis to detect clusters of users who, though currently active, could be considered for suspension since they exhibit similar behaviors with suspended users. finally, we confirm the usefulness of our analyzed features by emulating the twitter suspension mechanism with a supervised learning method, achieving very good precision and recall. | arxiv:1705.03345 |
in hedge funds, convex compensation schemes are adopted to stimulate a high - profit performance for portfolio managers. in economics, non - monotone risk aversion is proposed to argue that individuals may not be risk - averse when the wealth level is low. combining these two ingredients, we study the optimal control strategy of the manager in incomplete markets. generally, we propose a wide family of utility functions, the piecewise symmetric asymptotic hyperbolic absolute risk aversion ( psahara ) utility, to model the two ingredients, containing both non - concavity and non - differentiability as some abnormalities. technically, we propose an additional assumption and prove concavification techniques of non - - concave utility functions with a left unbounded domain in incomplete markets. next, we derive an explicit optimal control for the family of psahara utilities. this control is expressed into a unified four - term structure, featuring the asymptotic merton term. furthermore, we provide a detailed asymptotic analysis and numerical illustration of the optimal portfolio. we obtain several key insights, including that the convex compensation still induces a great risk - taking behavior in the case that the preference is modeled by sahara utility. finally, we conduct a real - data analysis of the u. s. stock market under the above model and conclude that the psahara portfolio is very risk - seeking and leads to a high return and a high volatility. | arxiv:2406.00435 |
the effect of angular momentum on galaxy formation and evolution has been studied for several decades. our recent two papers using illustristng - 100 simulation have revealed the acquisition path of the angular momentum from large - scale environment ( satellites within hundreds of kpc ) through the circum - galactic medium ( cgm ) to the stellar discs, putting forward the co - rotation scenario across the three distance scales. in real observations, although the rotation signature for the cgm and environmental three - dimensional ( 3d ) angular momentum are difficult to obtain, line - of - sight kinematics of group member galaxies and stellar disc kinematics of central galaxies are available utilizing existing group catalogue data and integral field unit ( ifu ) data. in this paper, we use ( 1 ) the group catalogue of sdss dr7 and manga ifu stellar kinematic maps and ( 2 ) the group catalogue of gama dr4 data and sami ifu stellar kinematic maps, to test if the prediction above can be seen in real data. we found the co - rotation pattern between stellar discs and satellites can be concluded with 99. 7 percent confidence level ( $ \ sim 3 \ sigma $ ) when combining the two datasets. and the random tests show that the signal can be scarcely drawn from random distribution. | arxiv:2310.10723 |
optically active defect centers in diamond are of considerable interest, and ab initio calculations have provided valuable insight into the physics of these systems. candidate structures for the xe center in diamond, for which little structural information is known, are modeled using density functional theory. the relative thermodynamic stabilities were calculated for two likely structural arrangements. the split - vacancy structure is found to be the most stable for all temperatures up to 1500 k. a vibrational analysis was also carried out, predicting raman - and ir - active modes which may aid in distinguishing between center structures. | arxiv:1201.4900 |
here we show that iapetus can serve to discriminate between satellite formation models. its accretion history can be understood in terms of a two - component gaseous subnebula, with a relatively dense inner region, and an extended tail out to the location of the irregular satellites, as in the semm model of mosqueira and estrada ( 2003a, b ). following giant planet formation, planetesimals in the feeding zone of jupiter and saturn become dynamically excited, and undergo a collisional cascade. ablation and capture of planetesimal fragments crossing the gaseous circumplanetary disks delivers enough collisional rubble to account for the mass budgets of the regular satellites of jupiter and saturn. this process can result in rock / ice fractionation provided the make up of the population of disk crossers is non - homogeneous, thus offering a natural explanation for the marked compositional differences between outer solar nebula objects and those that accreted in the subnebulae of the giant planets. consequently, our model leads to an enhancement of the ice content of iapetus, and to a lesser degree those of ganymede, titan and callisto, and accounts for the ( non - stochastic ) compositions of these large, low - porosity outer regular satellites of jupiter and saturn. ( abridged ) | arxiv:0908.2112 |
automatic summarization of legal case judgements has traditionally been attempted by using extractive summarization methods. however, in recent years, abstractive summarization models are gaining popularity since they can generate more natural and coherent summaries. legal domain - specific pre - trained abstractive summarization models are now available. moreover, general - domain pre - trained large language models ( llms ), such as chatgpt, are known to generate high - quality text and have the capacity for text summarization. hence it is natural to ask if these models are ready for off - the - shelf application to automatically generate abstractive summaries for case judgements. to explore this question, we apply several state - of - the - art domain - specific abstractive summarization models and general - domain llms on indian court case judgements, and check the quality of the generated summaries. in addition to standard metrics for summary quality, we check for inconsistencies and hallucinations in the summaries. we see that abstractive summarization models generally achieve slightly higher scores than extractive models in terms of standard summary evaluation metrics such as rouge and bleu. however, we often find inconsistent or hallucinated information in the generated abstractive summaries. overall, our investigation indicates that the pre - trained abstractive summarization models and llms are not yet ready for fully automatic deployment for case judgement summarization ; rather a human - in - the - loop approach including manual checks for inconsistencies is more suitable at present. | arxiv:2306.01248 |
we prove several versions of grothendieck ' s theorem for completely bounded linear maps $ t \ colon e \ to f ^ * $, when e and f are operator spaces. we prove that if e, f are $ c ^ * $ - algebras, of which at least one is exact, then every completely bounded $ t \ colon e \ to f ^ * $ can be factorized through the direct sum of the row and column hilbert operator spaces. equivalently t can be decomposed as $ t = t _ r + t _ c $ where $ t _ r $ ( resp. $ t _ c $ ) factors completely boundedly through a row ( resp. column ) hilbert operator space. this settles positively ( at least partially ) some earlier conjectures of effros - ruan and blecher on the factorization of completely bounded bilinear forms on $ c ^ * $ - algebras. moreover, our result holds more generally for any pair e, f of " exact " operator spaces. this yields a characterization of the completely bounded maps from a $ c ^ * $ - algebra ( or from an exact operator space ) to the operator hilbert space oh. as a corollary we prove that, up to a complete isomorphism, the row and column hilbert operator spaces and their direct sums are the only operator spaces e such that both e and its dual $ e ^ * $ are exact. we also characterize the schur multipliers which are completely bounded from the space of compact operators to the trace class. | arxiv:math/0108205 |
let $ k $ be a field with a discrete valuation, and let $ p $ and $ \ ell $ be ( possibly equal ) primes which are not necessarily different from the residue characteristic. given a superelliptic curve $ c : y ^ p = f ( x ) $ which has split degenerate reduction over $ k $, with jacobian denoted by $ j / k $, we describe the action of an element of the inertia group $ i _ k $ on the $ \ ell $ - adic tate module $ t _ \ ell ( j ) $ as a product of powers of certain transvections with respect to the $ \ ell $ - adic weil pairing and the canonical principal polarization of $ j $. the powers to which the transvections are taken are given by a formula depending entirely on the cluster data of the roots of the defining polynomial $ f $. this result is demonstrated using mumford ' s non - archimedean uniformization of the curve $ c $. | arxiv:2504.00205 |
we introduce two families of two - generator one - relator groups called primitive extension groups and show that a one - relator group is hyperbolic if its primitive extension subgroups are hyperbolic. this reduces the problem of characterising hyperbolic one - relator groups to characterising hyperbolic primitive extension groups. these new groups moreover admit explicit decompositions as graphs of free groups with adjoined roots. in order to obtain this result, we characterise $ 2 $ - free one - relator groups with exceptional intersection in terms of christoffel words, show that hyperbolic one - relator groups have quasi - convex magnus subgroups and build upon the one - relator tower machinery developed in the authors previous article. | arxiv:2211.04371 |
spintronic devices based on domain wall ( dw ) motion through ferromagnetic nanowire tracks have received great interest as components of neuromorphic information processing systems. previous proposals for spintronic artificial neurons required external stimuli to perform the leaking functionality, one of the three fundamental functions of a leaky integrate - and - fire ( lif ) neuron. the use of this external magnetic field or electrical current stimulus results in either a decrease in energy efficiency or an increase in fabrication complexity. in this work, we modify the shape of previously demonstrated three - terminal magnetic tunnel junction neurons to perform the leaking operation without any external stimuli. the trapezoidal structure causes shape - based dw drift, thus intrinsically providing the leaking functionality with no hardware cost. this lif neuron therefore promises to advance the development of spintronic neural network crossbar arrays. | arxiv:1905.05485 |
free electrons can screen out long - range coulomb interaction and destroy the polar distortion in some ferroelectric materials, whereas the coexistence of polar distortion and metallicity were found in several non - central - symmetric metals ( ncsms ). therefore, the mechanisms and designing of ncsms have attracted great interests. in this work, by first - principles calculation, we found the polar distortion in the lone - pair driven ferroelectric material pbtio $ _ 3 $ can not only persist, but also increase with electron doping. we further analyzed the mechanisms of the persisting of the polar distortion. we found that the ti site polar instability is suppressed but the pb site polar instability is intact with the electron doping. the pb - site instability is due to the lone - pair mechanism which can be viewed as a pseudo - jahn - teller effect, a mix of the ground state and the excited state by ion displacement from the central symmetric position. the lone - pair mechanism is not strongly affected by the electron doping because neither the ground state or the excited state involved is at the fermi energy. the enhancement of the polar distortion is related to the increasing of the ti ion size by doping. these results show the lone - pair stereoactive ions can be used in designing ncsms. | arxiv:1603.07418 |
we derive rigorously the reduced dynamical law for quantized vortex dynamics of the coupled nonlinear schr \ " odinger equation without josephson junction ( cnls ) when the core size of vortex $ \ varepsilon \ to 0 $. it is proved that when $ \ varepsilon \ to 0 $, the vortex motion of one component won ' t affect the vortex motion on the other component. moreover, the motion of vortices of each component follows the vortex motion law for the nonlinear schr \ " odinger. | arxiv:2411.14753 |
using the { \ it ab initio } anisotropic eliashberg theory including coulomb interactions, we investigate the electron - phonon interaction and the pairing mechanism in the recently - reported superconducting ca - intercalated bilayer graphene. we find that c $ _ 6 $ cac $ _ 6 $ can support phonon - mediated superconductivity with a critical temperature $ t _ { \ rm c } = $ 6. 8 - 8. 1 ~ k, in good agreement with experimental data. our calculations indicate that the low - energy ca $ _ { xy } $ vibrations are critical to the pairing, and that it should be possible to resolve two distinct superconducting gaps on the electron and hole fermi surface pockets. | arxiv:1601.06111 |
= = β { \ displaystyle \ infty } ( infinity symbol ) 1. the symbol is read as infinity. as an upper bound of a summation, an infinite product, an integral, etc., means that the computation is unlimited. similarly, β β { \ displaystyle - \ infty } in a lower bound means that the computation is not limited toward negative values. 2. β β { \ displaystyle - \ infty } and + β { \ displaystyle + \ infty } are the generalized numbers that are added to the real line to form the extended real line. 3. β { \ displaystyle \ infty } is the generalized number that is added to the real line to form the projectively extended real line. c { \ displaystyle { \ mathfrak { c } } } ( fraktur ) c { \ displaystyle { \ mathfrak { c } } } denotes the cardinality of the continuum, which is the cardinality of the set of real numbers. { \ displaystyle \ aleph } ( aleph ) with an ordinal i as a subscript, denotes the ith aleph number, that is the ith infinite cardinal. for example, 0 { \ displaystyle \ aleph _ { 0 } } is the smallest infinite cardinal, that is, the cardinal of the natural numbers. { \ displaystyle \ beth } ( bet ( letter ) ) with an ordinal i as a subscript, denotes the ith beth number. for example, 0 { \ displaystyle \ beth _ { 0 } } is the cardinal of the natural numbers, and 1 { \ displaystyle \ beth _ { 1 } } is the cardinal of the continuum. Ο { \ displaystyle \ omega } ( omega ) 1. denotes the first limit ordinal. it is also denoted Ο 0 { \ displaystyle \ omega _ { 0 } } and can be identified with the ordered set of the natural numbers. 2. with an ordinal i as a subscript, denotes the ith limit ordinal that has a cardinality greater than that of all preceding ordinals. 3. in computer science, denotes the ( unknown ) greatest lower bound for the exponent of the computational complexity of matrix multiplication. 4. written as a function of another function, it is used for comparing the asymptotic growth of two functions. see big o notation Β§ related asymptotic notation | https://en.wikipedia.org/wiki/Glossary_of_mathematical_symbols |
a boundary layer turbulence index ( tibl ) product has been developed to assess the potential for turbulence in the lower troposphere, generated using ruc - 2 numerical model data. the index algorithm approximates boundary layer turbulent kinetic energy by parameterizing vertical wind shear, responsible for mechanical production of tke, and kinematic heat flux, parameterized by the vertical temperature lapse rate and responsible for buoyant production of tke. validation for the tibl product has been conducted for selected nonconvective wind events during the 2008 winter season over the idaho national laboratory mesonet domain. this paper presents studies of four significant wind events between december 2007 and february 2008 over southeastern idaho. based on the favorable results highlighted from validation statistics and in the case studies, the ruc tibl product has demonstrated operational utility in assessing turbulence hazards to low - flying aircraft and ground transportation, and in the assessment of wildfire threat. | arxiv:0803.3945 |
quantum m - theory is formulated using the current algebra technique. the current algebra is based on a kac - moody algebra rather than usual finite dimensional lie algebra. specifically, i study the $ e _ { 11 } $ kac - moody algebra that was shown recently to contain all the ingredients of m - theory. both the internal symmetry and the external lorentz symmetry can be realized inside $ e _ { 11 } $, so that, by constructing the current algebra of $ e _ { 11 } $, i obtain both internal gauge theory and gravity theory. the energy - momentum tensor is constructed as the bilinear form of the currents, yielding a system of quantum equations of motion of the currents / fields. supersymmetry is incorporated in a natural way. the so - called " field - current identity " is built in and, for example, the gravitino field is itself a conserved super - current. one unanticipated outcome is that the quantum gravity equation is not identical to the one obtained from the einstein - hilbert action. | arxiv:1701.06894 |
mathematical modeling of fluid dynamics for computer graphics requires high levels of theoretical rigor to ensure visually plausible and computationally efficient simulations. this paper presents an in - depth theoretical framework analyzing the mathematical properties, such as stability, convergence, and error bounds, of numerical schemes used in fluid simulation. conditions for stability in semi - lagrangian and particle - based methods were derived, demonstrating that these methods remain stable under certain conditions. furthermore, convergence rates for navier - stokes discretizations were obtained, showing that numerical solutions converge to analytical solutions as spatial resolution and time step decrease. furthermore, new theoretical results were introduced on the maintenance of incompressibility and conservation of vorticity, which are crucial for the physical accuracy of simulations. the findings serve as a mathematical foundation for future research in adaptive fluid simulation, guiding the development of robust simulation techniques for real - time graphics applications. | arxiv:2411.01095 |
in this paper, we consider the cauchy problem to the ericksen - leslie system of liquid crystals in $ \ mathbb r ^ 3 $. global well - posedness of strong solutions are obtained under the condition that the product of $ \ | u _ 0 \ | _ 2 + \ | \ nabla d _ 0 \ | _ 2 $ and $ \ | \ nabla u _ 0 \ | _ 2 + \ | \ nabla ^ 2d _ 0 \ | _ 2 $ is suitably small. this result can be viewed as a supplement to the local existence and blow up criteria discussed in \ cite { hong1 }. | arxiv:1404.3254 |
oarpaf ( osservatorio astronomico regionale parco antola comune di fascia, italy ) hosts an 80cm astelco telescope with a gambato dome, sbig - stx camera, davis weather station, and sbig allsky camera. we present a layer - structured python3 framework to control these devices. layer 1 provides straightforward getter / setter interface for " atomic " operations on devices. layer 2 wraps the above mentioned atomic operations into " eso - style " templates, to perform sequences of common pointing, observation, and calibration operations called " observation blocks " ( obs ) that are run by a sequencer. layer 3 is a rest api based on http verbs to expose methods that control layer 1 devices and layer 2. we also present a web interface built on top of this layer. the work is part of the frame for remoting and robotizing the observatory. | arxiv:2501.08016 |
we prove a spectral inequality ( a specific type of uncertainty relation ) for schr \ " odinger operators with confinement potentials, in particular of shubin - type. the sensor sets are allowed to decay exponentially, where the precise allowed decay rate depends on the potential. the proof uses an interpolation inequality derived by carleman estimates, quantitative weighted $ l ^ 2 $ - estimates and an $ h ^ 1 $ - concentration estimate, all of them for functions in a spectral subspace of the operator. | arxiv:2206.08682 |
we prove that for operator spaces $ v $ and $ w $, the operator space $ v ^ { * * } \ otimes _ h w ^ { * * } $ can be completely isometrically embedded into $ ( v \ otimes _ h w ) ^ { * * } $, $ \ otimes _ h $ being the haagerup tensor product. it is also shown that, for exact operator spaces $ v $ and $ w $, a jointly completely bounded bilinear form on $ v \ times w $ can be extended uniquely to a separately $ w ^ * $ - continuous jointly completely bounded bilinear form on $ v ^ { * * } \ times w ^ { * * } $. this paves the way to obtain a canonical embedding of $ v ^ { * * } \ hat { \ otimes } w ^ { * * } $ into $ ( v \ hat { \ otimes } w ) ^ { * * } $ with a continuous inverse, where $ \ hat { \ otimes } $ is the operator space projective tensor product. further, for $ c ^ * $ - algebras $ a $ and $ b $, we study the ( closed ) ideal structure of $ a \ hat { \ otimes } b $, which, in particular, determines the lattice of closed ideals of $ b ( h ) \ hat { \ otimes } b ( h ) $ completely. | arxiv:1106.2644 |
continuous integration is an indispensable step of modern software engineering practices to systematically manage the life cycles of system development. developing a machine learning model is no difference - it is an engineering process with a life cycle, including design, implementation, tuning, testing, and deployment. however, most, if not all, existing continuous integration engines do not support machine learning as first - class citizens. in this paper, we present ease. ml / ci, to our best knowledge, the first continuous integration system for machine learning. the challenge of building ease. ml / ci is to provide rigorous guarantees, e. g., single accuracy point error tolerance with 0. 999 reliability, with a practical amount of labeling effort, e. g., 2k labels per test. we design a domain specific language that allows users to specify integration conditions with reliability constraints, and develop simple novel optimizations that can lower the number of labels required by up to two orders of magnitude for test conditions popularly used in real production systems. | arxiv:1903.00278 |
many models of dark matter scattering with baryons may be treated either as a simple contact interaction or as the exchange of a light mediator particle. we study an alternative, in which a continuum of light mediator states may be exchanged. this could arise, for instance, from coupling to a sector which is approximately conformal at the relevant momentum transfer scale. in the non - relativistic effective theory of dark matter - baryon scattering, which is useful for parametrizing direct detection signals, the effect of such continuum mediators is to multiply the amplitude by a function of the momentum transfer q, which in the simplest case is just a power law. we develop the basic framework and study two examples : the case where the mediator is a scalar operator coupling to the higgs portal ( which turns out to be highly constrained ) and the case of an antisymmetric tensor operator $ { \ cal o } _ { \ mu \ nu } $ that mixes with the hypercharge field strength and couples to dark matter tensor currents, which has an interesting viable parameter space. we describe the effect of such mediators on the cross sections and recoil energy spectra that could be observed in direct detection. | arxiv:1509.03628 |
tidal effects related to the traversability across thin shells are examined in spherically symmetric geometries. we focus mainly on shells separating inner from outer regions of gravastars ( de sitter - - i. e. $ \ lambda > 0 $ - - interior and schwarzschild exterior of mass parameter $ m $ ), but we also examine other related geometries by including the possibility of a negative cosmological constant and, besides, non trivial topologies where the shell separates two outer regions. the analysis is developed for radially traversing objects and for tides in both radial and transverse directions, which present difficulties of somewhat different nature. transverse tides across shells which satisfy the flare - out condition are the most troublesome, while shells in trivial topologies, i. e. geometries with one asymptotic region, are more indulgent with the issue of large tides. besides, contradicting other cases analyzed in previous works, we find that large radial tides cannot be avoided when traveling across the shell in the gravastar solution, but in non - trivial topologies they can. we study with special attention the traversability in practice of the transition layer in the thin - shell gravastar solution. in particular, a finite object which traverses radially the shell in a gravastar with $ \ sqrt { \ lambda } \ ll 1 / m $ undergoes a compression effect in both the transverse and the radial directions due to the tides associated to the thin layer. the results are interpreted in terms of the total momentum transfer obtained by integrating the travel time of the object. | arxiv:2407.11185 |
goods trade is a supply chain transaction that involves shippers buying goods from suppliers and carriers providing goods transportation. shippers are issued invoices from suppliers and carriers. shippers carry out goods receiving and invoice processing before payment processing of bills for suppliers and carriers, where invoice processing includes tasks like processing claims and adjusting the bill payments. goods receiving involves verification of received goods by the shipper ' s receiving team. invoice processing is carried out by the shipper ' s accounts payable team, which in turn is verified by the accounts receivable teams of suppliers and carriers. this paper presents a blockchain - based accounts payable system that generates claims for the deficiency in the goods received and accordingly adjusts the payment in the bills for suppliers and carriers. primary motivations for these supply chain organizations to adopt blockchain - based accounts payable systems are to eliminate the process redundancies ( accounts payable vs. accounts receivable ), to reduce the number of disputes among the transacting participants, and to accelerate the accounts payable processes via optimizations in the claims generation and blockchain - based dispute reconciliation. | arxiv:2103.02979 |
we introduce and study the block voter model with noise on two - dimensional square lattices using monte carlo simulations and finite - size scaling techniques. the model is defined by an outflow dynamics where a central set of $ n _ { pcs } $ spins, here denoted by persuasive cluster spins ( pcs ), tries to influence the opinion of their neighbouring counterparts. we consider the collective behaviour of the entire system with varying pcs size. when $ n _ { pcs } > 2 $, the system exhibits an order - disorder phase transition at a critical noise parameter $ q _ { c } $ which is a monotonically increasing function of the size of the persuasive cluster. we conclude that how large the pcs is more power of persuasion it has. it also seems that the resulting critical behaviour is ising - like independent of the range of the interactions. | arxiv:1105.1546 |
in this paper we explore the non - monotonic nature of entanglement of formation with respect to concurrence for pure bipartite states. for pure bipartite system, one of the basic physical reason of this non - monotonicity character is due to the existence of incomparable states, i. e., the pure bipartite states which are not convertible to each other by locc with certainty. | arxiv:0812.2877 |
an extension of the traditional modulation transfer function ( mtf ), the detective mtf, is proposed for the evaluation of the resolution of x - ray imaging detectors with non - uniform efficiency on the scale of individual detector elements. the dmtf is shown to give a better representation than does the mtf of the improved resolution reported when the readout of the detectors is enhanced. | arxiv:physics/9708025 |
the all - sky monitor ( asm ) on the rossi x - ray timing explorer ( rxte ) has been used to localize thirteen confirmed x - ray counterparts to gamma - ray bursts ( grbs ) detected over three years of operation. we quantify the errors in asm localizations of brief transient sources by using observations of persistent sources with well - known locations. we apply the results of this analysis to obtain accurate error boxes with reliable confidence levels for the thirteen grbs. in six of these thirteen cases, multiple detections by the asm allow the positions to be localized to a diamond of order ~ 15 ' x 3 '. in five further cases, the interplanetary network ( ipn ) constrains the usually ~ 3 deg. x 3 ' ( full - width ) asm error box to an area of a few tens of square arcminutes. this work adds eleven burst localizations to the list of ~ 60 well - localized grbs. | arxiv:astro-ph/9907332 |
we calculate the electron - mediated exchange interaction between two domain walls in magnetic wires. this corresponds to the equilibrium regime and, therefore, the interaction can be additionally controlled by an electric current. the exchange interaction is long ranged and oscillates as a function of the distance between the walls. it also depends oscillatory on the polarization angle of the walls, having the maximum value for collinear polarization. | arxiv:1111.3733 |
we report the discovery of year - scale x - ray variation in the nuclear region of the m87 by reanalyzing the 8 chandra observations from 2007 to 2008. the x - ray spectra are fitted and decomposed into the disk and flaring components. this year - scale x - ray variability can be explained quite well by a simple clumpy accretion model. we conclude that the central super - massive black hole of the m87 was accreting a cloud of $ \ sim0. 5 $ m $ _ \ odot $ at that time. | arxiv:2002.09122 |
fast radio bursts ( frbs ) are bright radio transient events, a subset of which have been localized to their host galaxies. their high dispersion measures offer valuable insights into the ionized plasma along their line of sight, enabling them to serve as probes of cosmological parameters. one of the major challenges in contemporary cosmology is the hubble tension - - an unresolved discrepancy between two independent methods of determining the universe ' s expansion rate, yielding differing values for the hubble constant. in this study, we analyze a sample of 64 extragalactic, localized frbs observed by various telescopes, employing bayesian analysis with distinct likelihood functions. our findings suggest that frbs serve as tracers of the hubble constant in the late - time universe. notably, our results exhibit smaller error bars compared to previous studies, and the derived hubble constant with 1 $ \ sigma $ error bars no longer overlap with those obtained from early - universe measurements. these results underscore the continuing tension between early - and late - time measurements of the hubble constant. | arxiv:2410.01974 |
recently, two concepts from optimal transport theory have successfully been brought to the gromov - - wasserstein ( gw ) setting. this introduces a linear version of the gw distance and multi - marginal gw transport. the former can reduce the computational complexity when computing all gw distances of a large set of inputs. the latter allows for a simultaneous matching of more than two marginals, which can for example be used to compute gw barycenters. the aim of this paper is to show an approximation result which characterizes the linear version as a limit of a multi - marginal gw formulation. | arxiv:2210.01596 |
we establish lower estimates for singular value gaps of free products of $ 1 $ - divergent semigroups $ \ gamma _ 1, \ gamma _ 2 \ subset \ mathsf { gl } _ d ( \ mathbb { k } ) $ which are in ping - pong position. as an application, we prove that if $ \ gamma _ 1 $ and $ \ gamma _ 2 $ are quasi - isometrically embedded subgroups in ping pong position, then the group they generate $ \ langle \ gamma _ 1, \ gamma _ 2 \ rangle $ is also quasi - isometrically embedded. in addition, we establish that the class of linear finitely generated groups, admitting a faithful linear representation over $ \ mathbb { r } $ which is a quasi - isometric embedding, is closed under free products. | arxiv:2409.20330 |
semantic communication ( semcom ) has been a transformative paradigm, emphasizing the precise exchange of meaningful information over traditional bit - level transmissions. however, existing semcom research, primarily centered on simplified scenarios like single - pair transmissions with direct wireless links, faces significant challenges when applied to real - world radio access networks ( rans ). this article introduces a semantic - aware radio access network ( s - ran ), offering a holistic systematic view of semcom beyond single - pair transmissions. we begin by outlining the s - ran architecture, introducing new physical components and logical functions along with key design challenges. we then present transceiver design for end - to - end transmission to overcome conventional semcom transceiver limitations, including static channel conditions, oversimplified background knowledge models, and hardware constraints. later, we delve into the discussion on radio resource management for multiple users, covering semantic channel modeling, performance metrics, resource management algorithms, and a case study, to elaborate distinctions from resource management for legacy rans. finally, we highlight open research challenges and potential solutions. the objective of this article is to serve as a basis for advancing semcom research into practical wireless systems. | arxiv:2407.11161 |
touch holds a pivotal position in enhancing the perceptual and interactive capabilities of both humans and robots. despite its significance, current tactile research mainly focuses on visual and tactile modalities, overlooking the language domain. inspired by this, we construct touch100k, a paired touch - language - vision dataset at the scale of 100k, featuring tactile sensation descriptions in multiple granularities ( i. e., sentence - level natural expressions with rich semantics, including contextual and dynamic relationships, and phrase - level descriptions capturing the key features of tactile sensations ). based on the dataset, we propose a pre - training method, touch - language - vision representation learning through curriculum linking ( tlv - link, for short ), inspired by the concept of curriculum learning. tlv - link aims to learn a tactile representation for the gelsight sensor and capture the relationship between tactile, language, and visual modalities. we evaluate our representation ' s performance across two task categories ( namely, material property identification and robot grasping prediction ), focusing on tactile representation and zero - shot touch understanding. the experimental evaluation showcases the effectiveness of our representation. by enabling tlv - link to achieve substantial improvements and establish a new state - of - the - art in touch - centric multimodal representation learning, touch100k demonstrates its value as a valuable resource for research. project page : https : / / cocacola - lab. github. io / touch100k /. | arxiv:2406.03813 |
in this paper, we introduce famma, an open - source benchmark for \ underline { f } in \ underline { a } ncial \ underline { m } ultilingual \ underline { m } ultimodal question \ underline { a } nswering ( qa ). our benchmark aims to evaluate the abilities of large language models ( llms ) in answering complex reasoning questions that require advanced financial knowledge. the benchmark has two versions : famma - basic consists of 1, 945 questions extracted from university textbooks and exams, along with human - annotated answers and rationales ; famma - livepro consists of 103 novel questions created by human domain experts, with answers and rationales held out from the public for a contamination - free evaluation. these questions cover advanced knowledge of 8 major subfields in finance ( e. g., corporate finance, derivatives, and portfolio management ). some are in chinese or french, while a majority of them are in english. each question has some non - text data such as charts, diagrams, or tables. our experiments reveal that famma poses a significant challenge on llms, including reasoning models such as gpt - o1 and deepseek - r1. additionally, we curated 1, 270 reasoning trajectories of deepseek - r1 on the famma - basic data, and fine - tuned a series of open - source qwen models using this reasoning data. we found that training a model on these reasoning trajectories can significantly improve its performance on famma - livepro. we released our leaderboard, data, code, and trained models at https : / / famma - bench. github. io / famma /. | arxiv:2410.04526 |
a novel proposal is outlined to determine scattering amplitudes from finite - volume spectral functions. the method requires extracting smeared spectral functions from finite - volume euclidean correlation functions, with a particular complex smearing kernel of width $ \ epsilon $ which implements the standard $ i \ epsilon $ - prescription. in the $ l \ to \ infty $ limit these smeared spectral functions are therefore equivalent to minkowskian correlators with a specific time ordering to which a modified lsz reduction formalism can be applied. the approach is presented for general $ m \ to n $ scattering amplitudes ( above arbitrary inelastic thresholds ) for a single - species real scalar field, although generalization to arbitrary spins and multiple coupled channels is likely straightforward. processes mediated by the single insertion of an external current are also considered. numerical determination of the finite - volume smeared spectral function is discussed briefly and the interplay between the finite volume, euclidean signature, and time - ordered $ i \ epsilon $ - prescription is illustrated perturbatively in a toy example. | arxiv:1903.11735 |
analog gravity experiments, such as those realized in bose - einstein condensates, often aim at simulating cosmological pair production due to the dynamical expansion of the universe. however, these experiments have a start and an end, which introduces unavoidable transitions out of and into static regimes that alter the intended expansion profile. we show that the resulting particle spectra can be overwhelmingly dominated by these transition periods, which calls for a careful interpretation of experimental outcomes. in prospective schwinger effect experiments, by contrast, transition effects do not dominate particle production, and such a reinterpretation may not be necessary. | arxiv:2505.04473 |
the ` ` classical brst construction ' ' as developed by batalin - fradkin - vilkovisky is a homological construction for the reduction of the poisson algebra $ p = c ^ \ infty ( w ) $ of smooth functions on a poisson manifold $ w $ by the ideal $ i $ of functions which vanish on a constraint locus. this ideal is called first class if $ i $ is closed under the poisson bracket ; geometers refer to the constraint locus as coisotropic. the physicists ' model is crucially a differential poisson algebra extension of a poisson algebra $ p $ ; its differential contains a piece which reinvented the koszul complex for the ideal $ i $ and a piece which looks like the cartan - chevalley - eilenberg differential. the present paper is concerned purely with the homological ( poisson ) algebraic structures, using the notion of ` ` model ' ' from rational homotopy theory and the techniques of homological perturbation theory to establish some of the basic results explaining the mathematical existence of the classical brst - bfv construction. although the usual treatment of bfv is basis dependent ( individual constraints ) and nominally finite dimensional, i take care to avoid assumptions of finite dimensionality and work more invariantly in terms of the ideal. in particular, the techniques are applied to the ` irregular ' case ( the ideal is not generated by a regular sequence of constraints ), although the geometric interpretation is less complete. | arxiv:q-alg/9603021 |
consuming news from social media is becoming increasingly popular. social media appeals to users due to its fast dissemination of information, low cost, and easy access. however, social media also enables the widespread of fake news. because of the detrimental societal effects of fake news, detecting fake news has attracted increasing attention. however, the detection performance only using news contents is generally not satisfactory as fake news is written to mimic true news. thus, there is a need for an in - depth understanding on the relationship between user profiles on social media and fake news. in this paper, we study the challenging problem of understanding and exploiting user profiles on social media for fake news detection. in an attempt to understand connections between user profiles and fake news, first, we measure users ' sharing behaviors on social media and group representative users who are more likely to share fake and real news ; then, we perform a comparative analysis of explicit and implicit profile features between these user groups, which reveals their potential to help differentiate fake news from real news. to exploit user profile features, we demonstrate the usefulness of these user profile features in a fake news classification task. we further validate the effectiveness of these features through feature importance analysis. the findings of this work lay the foundation for deeper exploration of user profile features of social media and enhance the capabilities for fake news detection. | arxiv:1904.13355 |
we present deep co observations of ngc6240 performed with the iram plateau de bure interferometer ( pdbi ). ngc6240 is the prototypical example of a major galaxy merger in progress, caught at an early stage, with an extended, strongly - disturbed butterfly - like morphology and the presence of a heavily obscured active nucleus in the core of each progenitor galaxy. the co line shows a skewed profile with very broad and asymmetric wings detected out to velocities of - 600 km / s and + 800 km / s with respect to the systemic velocity. the pdbi maps reveal the existence of two prominent structures of blueshifted co emission. one extends eastward, i. e. approximately perpendicular to the line connecting the galactic nuclei, over scales of ~ 7 kpc and shows velocities up to - 400 km / s. the other extends southwestward out to ~ 7 kpc from the nuclear region, and has a velocity of - 100 km / s with respect to the systemic one. interestingly, redshifted emission with velocities 400 to 800 km / s is detected around the two nuclei, extending in the east - west direction, and partly overlapping with the eastern blue - shifted structure, although tracing a more compact region of size ~ 1. 7 kpc. the overlap between the southwestern co blob and the dust lanes seen in hst images, which are interpreted as tidal tails, indicates that the molecular gas is deeply affected by galaxy interactions. the eastern blueshifted co emission is co - spatial with an halpha filament that is associated with strong h2 and soft x - ray emission. the analysis of chandra x - ray data provides strong evidence for shocked gas at the position of the halpha emission. its association with outflowing molecular gas supports a scenario where the molecular gas is compressed into a shock wave that propagates eastward from the nuclei. if this is an outflow, the agn are likely the driving force. | arxiv:1211.0841 |
federated learning ( fl ) is a machine learning technique that aims at training an algorithm across decentralized entities holding their local data private. wireless mobile networks allow users to communicate with other fixed or mobile users. the road traffic network represents an infrastructure - based configuration of a wireless mobile network where the connected and automated vehicles ( cav ) represent the communicating entities. applying fl in a wireless mobile network setting gives rise to a new threat in the mobile environment that is very different from the traditional fixed networks. the threat is due to the intrinsic characteristics of the wireless medium and is caused by the characteristics of the vehicular networks such as high node - mobility and rapidly changing topology. most cyber defense techniques depend on highly reliable and connected networks. this paper explores falsified information attacks, which target the fl process that is ongoing at the rsu. we identified a number of attack strategies conducted by the malicious cavs to disrupt the training of the global model in vehicular networks. we show that the attacks were able to increase the convergence time and decrease the accuracy the model. we demonstrate that our attacks bypass fl defense strategies in their primary form and highlight the need for novel poisoning resilience defense mechanisms in the wireless mobile setting of the future road networks. | arxiv:2102.13256 |
in this paper, we generalize the concepts of level and sublevels of a composition algebra to algebras obtained by the cayley - dickson process. in 1967, r. b. brown constructed, for every $ t \ in \ bbb { n }, $ a division algebra $ a _ { t } $ of dimension $ 2 ^ { t } $ over the power - series field $ k \ { x _ { 1 }, x _ { 2 },..., x _ { t } \ }. $ this gives us the possibility to construct a division algebra of dimension 2 $ ^ { t } $ and prescribed level 2 $ ^ { k } $ $ k, t \ in \ bbb { n } ^ { * }. $ | arxiv:1001.1440 |
the least - action principle ( lap ) method is used on four galaxy redshift surveys to measure the density parameter omega _ m and the matter and galaxy - galaxy power spectra. the datasets are pscz, ors, mark iii and sfi. the lap method is applied on the surveys simultaneously, resulting in an overconstrained dynamical system that describes the cosmic overdensities and velocity flows. the system is solved by relaxing the constraint that each survey imposes upon the cosmic fields. a least - squares optimization of the errors that arise in the process yields the cosmic fields and the value of omega _ m that is the best fit to the ensemble of datasets. the analysis has been carried out with a high - resolution gaussian smoothing of 500 km / s and over a spherical selected volume of radius 9, 000 km / s. we have assigned a weight to each survey, depending on their density of sampling, and this parameter determines their relative influence in limiting the domain of the overall solution. the influence of each survey on the final value of omega _ m, the cosmographical features of the cosmic fields and the power spectra largely depends on the distribution function of the errors in the relaxation of the constraints. we find that pscz and mark iii are closer to the final solution than ors and sfi. the likelihood analysis yields omega _ m = 0. 37 \ pm 0. 01 to 1sigma level. pscz and sfi are the closest to this value, whereas ors and mark iii predict a somewhat lower omega _ m. the model of bias employed is a scale - dependent one, and we retain up to 42 bias coefficients b _ { rl } in the spherical harmonics formalism. the predicted power spectra are estimated in the range of wavenumbers 0. 02 - 0. 49h mpc ^ { - 1 }, and we compare these results with measurements recently reported in the literature. | arxiv:astro-ph/0102319 |
in a previous paper, the general approach for treatment of algebraic equations of different order in gravity theory was exposed, based on the important distinction between covariant and contravariant metric tensor components. in the present second part of the paper it has been shown that a multivariable cubic algebraic equation can also be parametrized by means of complicated, irrational and non - elliptic functions, depending on the elliptic weierstrass function and its derivative. as a model example, the proposed before cubic algebraic equation for reparametrization invariance of the gravitational lagrangian has been investigated. this is quite different from the standard algebraic geometry approach, where only the parametrization of two - dimensional cubic algebraic equations has been considered. also, the possible applications in modern cosmological theories has been commented. | arxiv:0911.1051 |
in this paper we provide a no - scale supergravity scenario of hybrid inflation with r - symmetry being broken maximally. we investigate the inflation dynamics in details in both cases of pure f - term hybrid inflation and when adding constant fayet - iliopoulos d - terms. the effective inflation potential is asymptotically flat in a region of the parameter space in both cases. we explore all regions in the parameter space when discussing the constraints from the observables. we point out a connection between inflation, r - symmetry breaking and gut scales. the moduli backreaction and susy breaking effects are investigated in a specific stabilization mechanism. we emphasis that a successful reheating is not affected by r - symmetry breaking, but it has interesting consequences. we study the reheating in flipped gut model. we argue in favor of $ z _ 2 $ symmetry associated with flipped gut models to avoid phenomenologically dangerous operators and allow for decay channels for the inflaton to right - handed neutrinos ( sneutrinos ). | arxiv:2009.14149 |
context. thanks to the heroic observational campaigns carried out in recent years we now have large samples of metal - poor stars for which measurements of detailed abundances exist. [... ] these data hold important clues on the nature of the contribution of the first stellar generations to the enrichment of our galaxy. aims. we aim to explain the scatter in sr, ba, y, and eu abundance ratio diagrams unveiled by the metal - poor halo stars. methods. we computed inhomogeneous chemical evolution models for the galactic halo assuming different scenarios for the r - process site : the electron - capture supernovae ( ec ) and the magnetorotationally driven ( mrd ) supernovae scenario. we also considered models with and without the contribution of fast - rotating massive stars ( spinstars ) to an early enrichment by the s - process. a detailed comparison with the now large sample of stars with measured abundances of sr, ba, y, eu, and fe is provided ( both in terms of scatter plots and number distributions for several abundance ratios ). results. the scatter observed in these abundance ratios of the very metal - poor stars ( with [ fe / h ] < - 2. 5 ) can be explained by combining the s - process production in spinstars, and the r - process contribution coming from massive stars. for the r - process we have developed models for both the ec and the mrd scenario that match the observations. conclusions. with the present observational and theoretical constraints we cannot distinguish between the ec and the mrd scenario in the galactic halo. independently of the r - process scenarios adopted, the production of elements by an s - process in spinstars is needed to reproduce the spread in abundances of the light neutron capture elements ( sr and y ) over heavy neutron capture elements ( ba and eu ). we provide a way to test our suggestions by means of the distribution of the ba isotopic ratios in a [ ba / fe ] or [ sr / ba ] vs. [ fe / h ] diagram. | arxiv:1403.8070 |
recent iterated response ( ir ) models of pragmatics conceptualize language use as a recursive process in which agents reason about each other to increase communicative efficiency. these models are generally defined over complete utterances. however, there is substantial evidence that pragmatic reasoning takes place incrementally during production and comprehension. we address this with an incremental ir model. we compare the incremental and global versions using computational simulations, and we assess the incremental model against existing experimental data and in the tuna corpus for referring expression generation, showing that the model can capture phenomena out of reach of global versions. | arxiv:1810.00367 |
we present the theory of resonance fluorescence from an asymmetric quantum dot driven by a two - component electromagnetic field with two different frequencies, polarizations and amplitudes ( bichromatic field ) in the regime of strong light - matter coupling. it follows from the elaborated theory that the broken inversion symmetry of the driven quantum system and the bichromatic structure of the driving field result in unexpected features of the resonance fluorescence, including the infinite set of mollow triplets, the quench of fluorescence peaks induced by the dressing field, and the oscillating behavior of the fluorescence intensity as a function of the dressing field amplitude. these quantum phenomena are of general physical nature and, therefore, can take place in various double - driven quantum systems with broken inversion symmetry. | arxiv:1611.03678 |
the ground - state spin of optically active defects in hexagonal boron nitride ( hbn ) offers a promising platform for quantum information applications, such as qubits for quantum computing and nanoscale sensing. a key characteristic of a qubit is its decoherence time, as its duration and controllability are critical for practical applications in quantum technologies. in this work, we investigate the electron spin dephasing time of the negatively charged boron vacancies, $ v _ { b } $ centers, in the hbn lattice by considering the dipolar hyperfine as well as spin - phonon interactions. we employ an approximate method based on the holstein - primakoff transformation to take into account a large number of nuclear spins and debye model to consider the effect of lattice phonons. we show that, in the presence of the dipolar hyperfine interactions, hahn - echo coherence time of the $ v _ { b } $ electron spin is approximately $ 30 \ : \ mathrm { \ mu s } $ at room temperature. our results provide a step forward in understanding the $ v _ { b } $ defect decoherence in the hbn, which might be used for quantum information applications. | arxiv:2501.08055 |
transfer learning aims to learn classifiers for a target domain by transferring knowledge from a source domain. however, due to two main issues : feature discrepancy and distribution divergence, transfer learning can be a very difficult problem in practice. in this paper, we present a framework called tlf that builds a classifier for the target domain having only few labeled training records by transferring knowledge from the source domain having many labeled records. while existing methods often focus on one issue and leave the other one for the further work, tlf is capable of handling both issues simultaneously. in tlf, we alleviate feature discrepancy by identifying shared label distributions that act as the pivots to bridge the domains. we handle distribution divergence by simultaneously optimizing the structural risk functional, joint distributions between domains, and the manifold consistency underlying marginal distributions. moreover, for the manifold consistency we exploit its intrinsic properties by identifying k nearest neighbors of a record, where the value of k is determined automatically in tlf. furthermore, since negative transfer is not desired, we consider only the source records that are belonging to the source pivots during the knowledge transfer. we evaluate tlf on seven publicly available natural datasets and compare the performance of tlf against the performance of fourteen state - of - the - art techniques. we also evaluate the effectiveness of tlf in some challenging situations. our experimental results, including statistical sign test and nemenyi test analyses, indicate a clear superiority of the proposed framework over the state - of - the - art techniques. | arxiv:2108.12293 |
we elucidate why the 1 - wasserstein distance $ w _ 1 $ coincides with the area between the two marginal cumulative distribution functions ( cdfs ). we first describe the wasserstein distance in terms of copulas, and then show that $ w _ 1 $ with the euclidean distance is attained with the $ m $ copula. two random variables whose dependence is given by the $ m $ copula manifest perfect ( positive ) dependence. if we express the random variables in terms of their cdfs, it is intuitive to see that the distance between two such random variables coincides with the area between the two cdfs. | arxiv:2111.03570 |
one of the main tasks of actuaries and data scientists is to build good predictive models for certain phenomena such as the claim size or the number of claims in insurance. these models ideally exploit given feature information to enhance the accuracy of prediction. this user guide revisits and clarifies statistical techniques to assess the calibration or adequacy of a model on the one hand, and to compare and rank different models on the other hand. in doing so, it emphasises the importance of specifying the prediction target functional at hand a priori ( e. g. the mean or a quantile ) and of choosing the scoring function in model comparison in line with this target functional. guidance for the practical choice of the scoring function is provided. striving to bridge the gap between science and daily practice in application, it focuses mainly on the pedagogical presentation of existing results and of best practice. the results are accompanied and illustrated by two real data case studies on workers ' compensation and customer churn. | arxiv:2202.12780 |
we evaluate the chemical potential of a one - dimensional quantum dot, coupled to an atomic force microscope tip. the dot is described within the luttinger liquid framework and the conductance peaks positions as a function of the tip location are calculated in the linear and non - linear transport regimes for an arbitrary number of particles. the differences between the chemical potential oscillations induced by friedel and wigner terms are carefully analyzed in the whole range of interaction strength. it is shown that friedel oscillations, differently from the wigner ones, are sensitive probes to detect excited spin states and collective spin density waves involved in the transport. | arxiv:1211.5165 |
recently, from the hubble space telescope ( hst ) images of one of the large magellanic cloud ( lmc ) events taken 6. 3 years after the original lensing measurement, alcock et al. were able to directly image the lens. although the first resolved lens was identified for an lmc event, much more numerous lenses are expected to be resolved for galactic bulge events. in this paper, we estimate the fraction of galactic bulge events whose lenses can be directly imaged under the assumption that all bulge events are caused by normal stars. for this determination, we compute the distribution of lens proper motions of the currently detected galactic bulge events based on standard models of the geometrical and kinematical distributions of lenses and their mass function. we then apply realistic criteria for lens resolution, and the result is presented as a function of the time elapsed after an original lensing measurement, $ \ delta t $. if followup observations are performed by using an instrument with a resolving power of \ theta _ { psf } = 0. 1 ' ', which corresponds to that of hst equipped with the new advanced camera for surveys, we estimate that lenses can be resolved for ~ 3 % and 22 % of disk - bulge events and for ~ 0. 3 % and 6 % of bulge self - lensing events after $ \ delta t = 10 $ and 20 years, respectively. the fraction increases substantially with the increase of the resolving power. if the instrument has a resolution of \ theta _ { psf } = 0. 05 ' ', which can be achieved by the { \ it next generation space telescope }, we estimate that lenses can be resolved for $ \ sim 22 % $ and 45 % of disk - bulge events and for ~ 6 % and 23 % of bulge self - lensing events after \ delta t = 10 and 20 years, respectively. | arxiv:astro-ph/0209352 |
sequential decision - making under uncertainty is present in many important problems. two popular approaches for tackling such problems are reinforcement learning and online search ( e. g., monte carlo tree search ). while the former learns a policy by interacting with the environment ( typically done before execution ), the latter uses a generative model of the environment to sample promising action trajectories at decision time. decision - making is particularly challenging in non - stationary environments, where the environment in which an agent operates can change over time. both approaches have shortcomings in such settings - - on the one hand, policies learned before execution become stale when the environment changes and relearning takes both time and computational effort. online search, on the other hand, can return sub - optimal actions when there are limitations on allowed runtime. in this paper, we introduce \ textit { policy - augmented monte carlo tree search } ( pa - mcts ), which combines action - value estimates from an out - of - date policy with an online search using an up - to - date model of the environment. we prove theoretical results showing conditions under which pa - mcts selects the one - step optimal action and also bound the error accrued while following pa - mcts as a policy. we compare and contrast our approach with alphazero, another hybrid planning approach, and deep q learning on several openai gym environments. through extensive experiments, we show that under non - stationary settings with limited time constraints, pa - mcts outperforms these baselines. | arxiv:2401.03197 |
in vanadium dioxide, the interplay between coherent lattice transformation and electronic correlation drives an insulator - to - metal transition ( imt ). this phase commutation can be triggered by temperature, pressure, doping or deposition of optical energy. here we demonstrate that an atomically - strong terahertz electric field initiates a metastable ultrafast imt in vanadium dioxide without a concomitant lattice transformation. the free - space terahertz field acts as off - resonant excitation with photon energy below the lattice phonons and the interband transitions. differently from optical and infrared excitation, terahertz interaction leads to a full imt by interband zener tunneling with a negligible entropy deposition. in previous experiments the temporal dynamics of imt in vo2 could be only indirectly inferred. we disentangle the electronic and lattice contributions to the imt on a sub - picosecond timescale. near the critical temperature the imt becomes dissipative and the terahertz field concludes the lattice - assisted metallic nucleation initiated by heating. the method of strong - field induced phase transition presented here is applicable to a wide class of strongly correlated systems and will enable the discovery of novel metastable phases. | arxiv:1706.00616 |
let x be a compact kahler holomorphic - symplectic manifold, which is deformation equivalent to the hilbert scheme of length n subschemes of a k3 surface. let l be a nef line - bundle on x, such that the 2n - th power of c _ 1 ( l ) vanishes and c _ 1 ( l ) is primitive. assume that the two dimensional subspace h ^ { 2, 0 } ( x ) + h ^ { 0, 2 } ( x ), of the second cohomology of x with complex coefficients, intersects trivially the integral cohomology. we prove that the linear system of l is base point free and it induces a lagrangian fibration on x. in particular, the line - bundle l is effective. a determination of the semi - group of effective divisor classes on x follows, when x is projective. for a generic such pair ( x, l ), not necessarily projective, we show that x is bimeromorphic to a tate - shafarevich twist of a moduli space of stable torsion sheaves, each with pure one dimensional support, on a projective k3 surface. | arxiv:1301.6584 |
supervised deep learning models depend on massive labeled data. unfortunately, it is time - consuming and labor - intensive to collect and annotate bitemporal samples containing desired changes. transfer learning from pre - trained models is effective to alleviate label insufficiency in remote sensing ( rs ) change detection ( cd ). we explore the use of semantic information during pre - training. different from traditional supervised pre - training that learns the mapping from image to label, we incorporate semantic supervision into the self - supervised learning ( ssl ) framework. typically, multiple objects of interest ( e. g., buildings ) are distributed in various locations in an uncurated rs image. instead of manipulating image - level representations via global pooling, we introduce point - level supervision on per - pixel embeddings to learn spatially - sensitive features, thus benefiting downstream dense cd. to achieve this, we obtain multiple points via class - balanced sampling on the overlapped area between views using the semantic mask. we learn an embedding space where background and foreground points are pushed apart, and spatially aligned points across views are pulled together. our intuition is the resulting semantically discriminative representations invariant to irrelevant changes ( illumination and unconcerned land covers ) may help change recognition. we collect large - scale image - mask pairs freely available in the rs community for pre - training. extensive experiments on three cd datasets verify the effectiveness of our method. ours significantly outperforms imagenet pre - training, in - domain supervision, and several ssl methods. empirical results indicate our pre - training improves the generalization and data efficiency of the cd model. notably, we achieve competitive results using 20 % training data than baseline ( random initialization ) using 100 % data. our code is available. | arxiv:2205.13769 |
the $ \ alpha ^ 4 $ contribution to the lepton $ g - 2 $ from a gauge - invariant set of 18 feynman diagrams containing a light - by - light scattering subdiagram internally has been reevaluated by a method independent of the previous approach. comparison of two methods revealed a program error in the first version. correcting this error, the contributions of these 18 diagrams become - 0. 990 72 ( 10 ) $ ( \ alpha / \ pi ) ^ 4 $ and - 4. 432 43 ( 58 ) $ ( \ alpha / \ pi ) ^ 4 $ for the electron and muon $ g - 2 $, respectively. the correction is not large enough to affect the comparison between theory and experiment for the muon $ g - 2 $, but it does alter the inferred value for the fine structure constant $ \ alpha ^ { - 1 } $ by 6 ppb. | arxiv:hep-ph/0210322 |
in this mainly pedagogical article, we discuss under what circumstances measurements play a special role in quantum processes. in particular we discuss the following facts which appear to be a common area of confusion : i ) from a fundamental point of view measurements play no special role whatsoever : all dynamics that can be generated by measurements can be generated by unitary processes ( for which post - selection is no exception ), ii ) from a purely physical point of view, measurements are not " outside " of quantum mechanics, iii ) the only difference between the abilities of measurement - based protocols and unitary circuits for quantum computing comes from practical ( technology dependent ) constraints. we emphasize the importance of distinguishing between differences that are i ) fundamental but without physical import, ii ) fundamental and possess physical import, iii ) are not fundamental but have practical import. we also emphasize the importance of separating theoretical and experimental elements of measurement, primarily projection and amplification, which are physically very different. note that since we are concerned with facts regarding physical processes, this article has little if anything to do with interpretations of quantum mechanics. | arxiv:1707.04241 |
we consider a category of $ \ gl _ \ infty $ - crystals, whose objects are disjoint unions of extremal weight crystals of non - negative level with certain finite conditions on the multiplicity of connected components. we show that it is a monoidal category under tensor product of crystals and the associated grothendieck ring is anti - isomorphic to an ore extension of the character ring of integrable lowest weight $ \ gl _ \ infty $ - modules with respect to derivations shifting the characters of fundamental modules. a littlewood - richardson rule of extremal weight crystals with non - negative level is described explicitly in terms of classical littlewood - richardson coefficients. | arxiv:0909.1126 |
we discuss the possibility that the limiting speed ( c _ l ) appearing in lorentz equations might be different i. e., slightly larger than the observed speed of light ( c _ n ). we show that such a possibility can be tested by state - of - the - art michelson - morley experiments, but also by careful measurement of neutrino speeds. it would indeed suffice to show that c _ n < c _ neutrinos < = c _ l. quite interestingly, current limits from both approaches are competitive, in some circumstances. we also comment on competing tests using gamma - ray burst, assuming a dispersive character for the propagation of light. | arxiv:1202.2631 |
addressing the paramount need for precise calibration in superconducting quantum qubits, especially in frequency control, this study introduces a novel calibration scheme harnessing the principles of many - body localization ( mbl ). while existing strategies, such as google ' s snake algorithm, have targeted optimization of qubit frequency parameters, our mbl - based methodology emerges as a stalwart against noise, notably crosstalk and residual coupling errors, thereby significantly enhancing quantum processor fidelity and stability without necessitating extensive optimization computation. not only does this approach provide a marked improvement in performance, particularly where specific residue couplings are present, but it also presents a more resource - efficient and cost - effective calibration process. the research delineated herein affords fresh insights into advanced calibration strategies and propels forward the domain of superconducting quantum computation by offering a robust framework for future explorations in minimizing error and optimizing qubit performance. | arxiv:2310.06618 |
a decade ago kitaev ' s toric code model established the new paradigm of topological quantum computation. due to remarkable theoretical and experimental progress, the quantum simulation of such complex many - body systems is now within the realms of possibility. here we consider the question, to which extent the ground states of small toric code systems differ from lu - equivalent graph states. we argue that simplistic ( though experimentally attractive ) setups obliterate the differences between the toric code and equivalent graph states ; hence we search for the smallest setups on the square - and triangular lattice, such that the quasi - locality of the toric code hamiltonian becomes a distinctive feature. to this end, a purely geometric procedure to transform a given toric code setup into an lc - equivalent graph state is derived. in combination with an algorithmic computation of lc - equivalent graph states, we find the smallest non - trivial setup on the square lattice to contain 5 plaquettes and 16 qubits ; on the triangular lattice the number of plaquettes and qubits is reduced to 4 and 9, respectively. | arxiv:1206.6994 |
recently, antihydrogen atoms were trapped at cern in a magnetic minimum ( minimum - b ) trap formed by superconducting octupole and mirror magnet coils. the trapped antiatoms were detected by rapidly turning off these magnets, thereby eliminating the magnetic minimum and releasing any antiatoms contained in the trap. once released, these antiatoms quickly hit the trap wall, whereupon the positrons and antiprotons in the antiatoms annihilated. the antiproton annihilations produce easily detected signals ; we used these signals to prove that we trapped antihydrogen. however, our technique could be confounded by mirror - trapped antiprotons, which would produce seemingly - identical annihilation signals upon hitting the trap wall. in this paper, we discuss possible sources of mirror - trapped antiprotons and show that antihydrogen and antiprotons can be readily distinguished, often with the aid of applied electric fields, by analyzing the annihilation locations and times. we further discuss the general properties of antiproton and antihydrogen trajectories in this magnetic geometry, and reconstruct the antihydrogen energy distribution from the measured annihilation time history. | arxiv:1201.3944 |
we provide a detailed derivation of the mode - coupling equations for a colloidal liquid confined by two parallel smooth walls. we introduce irreducible memory kernels for the different relaxation channels thereby extending the projection operator technique to colloidal liquids in slit geometry. investigating both the collective dynamics as well as the tagged - particle motion, we prove that the mode - coupling functional assumes the same form as in the newtonian case corroborating the universality of the glass - transition singularity with respect to the microscopic dynamics. | arxiv:2007.08835 |
in the present study we attempt to incorporate the philosophical dialogue about physical reality into the instructional process of quantum mechanics. taking into account that both scientific realism and constructivism represent, on the basis of a rather broad spectrum, prevalent philosophical currents in the domain of science education, the compatibility of their essential commitments is examined against the conceptual structure of quantum theory. it is argued in this respect that the objects of science do not simply constitute ' personal constructions ' of the human mind for interpreting nature, as individualist constructivist consider, neither do they form products of a ' social construction ', as sociological constructivist assume ; on the contrary, they reflect objective structural aspects of the physical world. a realist interpretation of quantum mechanics, we suggest, is not only possible but also necessary for revealing the inner meaning of the theory ' s scientific content. it is pointed out, however, that a viable realist interpretation of quantum theory requires the abandonment or radical revision of the classical conception of physical reality and its traditional metaphysical presuppositions. to this end, we put forward an alternative to traditional realism interpretative scheme, that is in harmony with the findings of present - day quantum theory, and which, if adequately introduced into the instructional process of contemporary physics, is expected to promote the conceptual reconstruction of learners towards an appropriate view of nature. | arxiv:0904.2859 |
existing person re - identification ( re - id ) methods mostly follow a centralised learning paradigm which shares all training data to a collection for model learning. this paradigm is limited when data from different sources cannot be shared due to privacy concerns. to resolve this problem, two recent works have introduced decentralised ( federated ) re - id learning for constructing a globally generalised model ( server ) without any direct access to local training data nor shared data across different source domains ( clients ). however, these methods are poor on how to adapt the generalised model to maximise its performance on individual client domain re - id tasks having different re - id label spaces, due to a lack of understanding of data heterogeneity across domains. we call this poor ' model personalisation '. in this work, we present a new selective knowledge aggregation approach to decentralised person re - id to optimise the trade - off between model personalisation and generalisation. specifically, we incorporate attentive normalisation into the normalisation layers in a deep reid model and propose to learn local normalisation layers specific to each domain, which are decoupled from the global model aggregation in federated re - id learning. this helps to preserve model personalisation knowledge on each local client domain and learn instance - specific information. further, we introduce a dual local normalisation mechanism to learn generalised normalisation layers in each local model, which are then transmitted to the global model for central aggregation. this facilitates selective knowledge aggregation on the server to construct a global generalised model for out - of - the - box deployment on unseen novel domains. extensive experiments on eight person re - id datasets show that the proposed approach to decentralised re - id significantly outperforms the state - of - the - art decentralised methods. | arxiv:2110.11384 |
galactic rotation curves and lack of direct observations of dark matter may indicate that general relativity is not valid ( on galactic scale ) and should be replaced with another theory. there is the only variant of absolute parallelism which solutions are free of arising singularities, if d = 5 ( there is no room for changes ). this variant does not have a lagrangian, nor match gr : an equation of ` plain ' r ^ 2 - gravity ( ie without r - term ) is in sight instead. arranging an expanding o _ 4 - symmetrical solution as the basis of 5d cosmological model, and probing a universal _ function of mass distribution ( along very - very long the extra dimension ) to place into bi - laplace equation ( r ^ 2 gravity ), one can derive the law of gravitation : 1 / r ^ 2 transforms to 1 / r with distance ( not with acceleration ). | arxiv:0704.0857 |
we consider a class of black hole solutions to einstein ' s equations in d dimensions with a negative cosmological constant. these solutions have the property that the horizon is a ( d - 2 ) - dimensional einstein manifold of positive, zero, or negative curvature. the mass, temperature, and entropy are calculated. using the correspondence with conformal field theory, the phase structure of the solutions is examined, and used to determine the correct mass dependence of the bekenstein - hawking entropy. | arxiv:hep-th/9808032 |
computing the permanent of a non - negative matrix is a core problem with practical applications ranging from target tracking to statistical thermodynamics. however, this problem is also # p - complete, which leaves little hope for finding an exact solution that can be computed efficiently. while the problem admits a fully polynomial randomized approximation scheme, this method has seen little use because it is both inefficient in practice and difficult to implement. we present adapart, a simple and efficient method for drawing exact samples from an unnormalized distribution. using adapart, we show how to construct tight bounds on the permanent which hold with high probability, with guaranteed polynomial runtime for dense matrices. we find that adapart can provide empirical speedups exceeding 25x over prior sampling methods on matrices that are challenging for variational based approaches. finally, in the context of multi - target tracking, exact sampling from the distribution defined by the matrix permanent allows us to use the optimal proposal distribution during particle filtering. using adapart, we show that this leads to improved tracking performance using an order of magnitude fewer samples. | arxiv:1911.11856 |
we study cones and cylinders with a 1 - parametric isometric deformation carrying at least two planar curves, which remain planar during this continuous flexion and are located in non - parallel planes. we investigate this geometric / kinematic problem in the smooth and the discrete setting, as it is the base for a generalized construction of so - called t - hedral zipper tubes. in contrast to the cylindrical case, which can be solved easily, the conical one is more tricky, but we succeed to give a closed form solution for the discrete case, which is used to prove that these cones correspond to caps of bricard octahedra of the plane - symmetric type. for the smooth case we are able to reduce the problem by means of symbolic computation to an ordinary differential equation, but its solution remains an open problem. | arxiv:2212.05484 |
quantum monte carlo simulations are used to study the magnetic and transport properties of the hubbard model, and its strong coupling heisenberg limit, on a one - third depleted square lattice. this is the geometry occupied, after charge ordering, by the spin - $ \ frac { 1 } { 2 } $ ni $ ^ { 1 + } $ atoms in a single layer of the nickelate materials la $ _ 4 $ ni $ _ 3 $ o $ _ 8 $ and ( predicted ) la $ _ 3 $ ni $ _ 2 $ o $ _ 6 $. our model is also a description of strained graphene, where a honeycomb lattice has bond strengths which are inequivalent. for the heisenberg case, we determine the location of the quantum critical point ( qcp ) where there is an onset of long range antiferromagnetic order ( lrafo ), and the magnitude of the order parameter, and then compare with results of spin wave theory. an ordered phase also exists when electrons are itinerant. in this case, the growth in the antiferromagnetic structure factor coincides with the transition from band insulator to metal in the absence of interactions. | arxiv:1610.06459 |
quantum number - path entanglement is a resource for super - sensitive quantum metrology and in particular provides for sub - shotnoise or even heisenberg - limited sensitivity. however, such number - path entanglement has thought to have been resource intensive to create in the first place - - - typically requiring either very strong nonlinearities, or nondeterministic preparation schemes with feed - forward, which are difficult to implement. recently in [ phys. rev. lett. 114, 170802 ( 2015 ) ] we showed that number - path entanglement from a bosonsampling inspired interferometer can be used to beat the shot - noise limit. in this manuscript we compare and contrast different interferometric schemes, discuss resource counting, calculate exact quantum cram \ ' er - rao bounds, and study details of experimental errors. | arxiv:1610.07128 |
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