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diffusion regulates numerous natural processes and the dynamics of many successful generative models. existing models to learn the diffusion terms from observational data rely on complex bilevel optimization problems and model only the drift of the system. we propose a new simple model, jkonet *, which bypasses the complexity of existing architectures while presenting significantly enhanced representational capabilities : jkonet * recovers the potential, interaction, and internal energy components of the underlying diffusion process. jkonet * minimizes a simple quadratic loss and outperforms other baselines in terms of sample efficiency, computational complexity, and accuracy. additionally, jkonet * provides a closed - form optimal solution for linearly parametrized functionals, and, when applied to predict the evolution of cellular processes from real - world data, it achieves state - of - the - art accuracy at a fraction of the computational cost of all existing methods. our methodology is based on the interpretation of diffusion processes as energy - minimizing trajectories in the probability space via the so - called jko scheme, which we study via its first - order optimality conditions.
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arxiv:2406.12616
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the properties of the milky way ' s nuclear stellar disc give crucial information on the epoch of bar formation. mira variables are promising bright candidates to study the nuclear stellar disc, and through their period - age relation dissect its star formation history. we report on a sample of $ 1782 $ mira variable candidates across the central $ 3 \ times3 \, \ mathrm { deg } ^ 2 $ of the galaxy using the multi - epoch infrared vista variables in via lactea ( vvv ) survey. we describe the algorithms employed to select candidate variable stars and then model their light curves using periodogram and gaussian process methods. by combining with wise, 2mass and other archival photometry, we model the multi - band light curves to refine the periods and inspect the amplitude variation between different photometric bands. the infrared brightness of the mira variables means many are too bright and missed by vvv. however, our sample follows a well - defined selection function as expected from artificial star tests. the multi - band photometry is modelled using stellar models with circumstellar dust that characterise the mass loss rates. we demonstrate how $ \ gtrsim90 $ per cent of our sample is consistent with o - rich chemistry. comparison to period - luminosity relations demonstrates that the bulk of the short period stars are situated at the galactic centre distance. many of the longer period variables are very dusty, falling significantly under the o - rich magellanic cloud and solar neighbourhood period - luminosity relations and exhibit high mass - loss rates of $ \ sim2. 5 \ times10 ^ { - 5 } m _ \ odot \, \ mathrm { yr } ^ { - 1 } $. the period distribution appears consistent with the nuclear stellar disc forming $ \ gtrsim8 \, \ mathrm { gyr } $ ago although it is not possible to disentangle the relative contributions of the nuclear stellar disc and the contaminating bulge.
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arxiv:2208.04966
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in the cauchy problem of general relativity one considers initial data that satisfies certain constraints. the evolution equations guarantee that the evolved variables will satisfy the constraints at later instants of time. this is only true within the domain of dependence of the initial data. if one wishes to consider situations where the evolutions are studied for longer intervals than the size of the domain of dependence, as is usually the case in three dimensional numerical relativity, one needs to give boundary data. the boundary data should be specified in such a way that the constraints are satisfied everywhere, at all times. in this paper we address this problem for the case of general relativity linearized around minkowski space using the generalized einstein - christoffel symmetric hyperbolic system of evolution equations. we study the evolution equations for the constraints, specify boundary conditions for them that make them well posed and further choose these boundary conditions in such a way that the evolution equations for the metric variables are also well posed. we also consider the case of a manifold with a non - smooth boundary, as is the usual case of the cubic boxes commonly used in numerical relativity. the techniques discussed should be applicable to more general cases, as linearizations around more complicated backgrounds, and may be used to establish well posedness in the full non - linear case.
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arxiv:gr-qc/0209017
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we apply the recently proposed quantum extremal surface construction to calculate the page curve of the eternal reissner - nordstr \ " om black holes in four dimensions ignoring the backreaction and the greybody factor. without the island, the entropy of hawking radiation grows linearly with time, which results in the information paradox for the eternal black holes. by extremizing the generalized entropy that allows the contributions from the island, we find that the island extends to the outside the horizon of the reissner - nordstr \ " om black hole. when taking the effect of the islands into account, it is shown that the entanglement entropy of hawking radiation at late times for a given region far from the black hole horizon reproduces the bekenstein - hawking entropy of the reissner - nordstr \ " om black hole with an additional term representing the effect of the matter fields. the result is consistent with the finiteness of the entanglement entropy for the radiation from an eternal black hole. this facilitates to address the black hole information paradox issue in the current case under the above - mentioned approximations.
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arxiv:2101.06867
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diquark correlations are important in baryons, which can be modeled as quark - diquark bound states. in addition, diquarks could play a role in non - standard hadrons such as tetraquarks and pentaquarks. here, we obtain properties of these diquarks from the corresponding bound state equation, using a model for the effective quark - quark interaction that has proved successful in the light meson sector. subsequently, we use the same model to estimate the masses of the lightest diquark - diquark and diquark - antidiquark states.
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arxiv:nucl-th/0412059
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an overview of alice results on the measurement of j / { \ psi } production in pp collisions at $ \ sqrt { s } $ = 7 tev collected during the lhc run - 1 period is presented, as well as first results at forward rapidity from pp collisions at $ \ sqrt { s } $ = 13 tev collected during the lhc run - 2 period. in particular, the measurement of j / { \ psi } production as a function of transverse momentum and charged - particle multiplicity are discussed and compared to theoretical model calculations.
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arxiv:1704.04627
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we describe a one - parameter family of models of stable spherical stellar systems in which the phase - space distribution function depends only on energy. the models have similar density profiles in their outer parts ( $ \ rho \ propto r ^ { - 4 } $ ) and central power - law density cusps, $ \ rho \ propto r ^ { 3 - \ eta } $, $ 0 < \ eta \ le 3 $. the family contains the jaffe ( 1983 ) and hernquist ( 1990 ) models as special cases. we evaluate the surface brightness profile, the line - of - sight velocity dispersion profile, and the distribution function, and discuss analogs of king ' s core - fitting formula for determining mass - to - light ratio. we also generalize the models to a two - parameter family, in which the galaxy contains a central black hole ; the second parameter is the mass of the black hole. our models can be used to estimate the detectability of central black holes and the velocity - dispersion profiles of galaxies that contain central cusps, with or without a central black hole.
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arxiv:astro-ph/9309044
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in this paper we address the actuator / sensor allocation problem for linear time invariant ( lti ) systems. given the structure of an autonomous linear dynamical system, the goal is to design the structure of the input matrix ( commonly denoted by $ b $ ) such that the system is structurally controllable with the restriction that each input be dedicated, i. e., it can only control directly a single state variable. we provide a methodology that addresses this design question : specifically, we determine the minimum number of dedicated inputs required to ensure such structural controllability, and characterize, and characterizes all ( when not unique ) possible configurations of the \ emph { minimal } input matrix $ b $. furthermore, we show that the proposed solution methodology incurs \ emph { polynomial complexity } in the number of state variables. by duality, the solution methodology may be readily extended to the structural design of the corresponding minimal output matrix ( commonly denoted by $ c $ ) that ensures structural observability.
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arxiv:1210.6724
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we report a room - temperature optical reflectivity study performed on [ 112 ] - oriented cd $ _ 3 $ as $ _ 2 $ single crystals over a broad energy range under external pressure up to 10 gpa. the abrupt drop of the band dispersion parameter ( $ z $ - parameter ) and the interruption of the gradual redshift of the bandgap at $ \ sim $ 4 ~ gpa confirms the structural phase transition from a tetragonal to a monoclinic phase in this material. the pressure - induced increase of the overall optical conductivity at low energies and the continuous redshift of the high - energy bands indicate that the system evolves towards a topologically trivial metallic state, although a complete closing of the band gap could not be observed in the studied pressure range. furthermore, a detailed investigation of the low - pressure regime suggests the possible existence of an intermediate state between 2 and 4 ~ gpa, that might be a precursor of the structural phase transition or due to the lifted degeneracy of the dirac nodes. several optical parameters show yet another anomaly at 8 ~ gpa, where low - temperature superconductivity was found in an earlier study.
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arxiv:1708.00725
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visual and near - infrared colours are used to identify intermediate - age globular cluster in early - type galaxies. in ngc5846 and ngc4365 colour - colour diagrams ( v - i vs. v - k ) reveal a sub - population in the globular cluster systems with an age much younger than the expected old populations ( 13 - 15 gyr ). a comparison with ssp models dates the formation of this younger population 2 - 7 gyr back. further evidence for multiple star formation events is given by the age distribution in both systems and the comparison to models. our photometric age determination was confirmed by spectroscopy for a small sample of the clusters in ngc4365.
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arxiv:astro-ph/0210420
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the study of the top quark ' s properties is an important part of the lhc programme. in earlier work, we have studied the rare decay $ t \ to b \ bar b c $, using effective operators to capture the effects of physics beyond the standard model. however top decay is primarily sensitive to new physics in the sub - tev energy regime. if this new physics resides at a higher energy scale, then one needs to turn to single - top production. in this paper, we use the $ s $ - channel and $ t $ - channel single - top production measurements to constrain the new physics parameter space associated with such contact interactions. we also study the net top polarization as a means to distinguish between contributions from operators involving different fermion chiralities and lorentz structures.
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arxiv:1712.08120
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the noncommutative selfdual \ phi ^ 3 model in 6 dimensions is quantized and essentially solved, by mapping it to the kontsevich model. the model is shown to be renormalizable and asymptotically free, and solvable genus by genus. it requires both wavefunction and coupling constant renormalization. the exact ( all - order ) renormalization of the bare parameters is determined explicitly, which turns out to depend on the genus 0 sector only. the running coupling constant is also computed exactly, which decreases more rapidly than predicted by the one - loop beta function. a phase transition to an unstable phase is found.
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arxiv:hep-th/0607235
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we study statistical properties of peculiar responses in glassy systems at mesoscopic scales based on a class of mean - field spin - glass models which exhibit 1 step replica symmetry breaking. under variation of a generic external field, a finite - sized sample of such a system exhibits a series of step wise responses which can be regarded as a finger print of the sample. we study in detail the statistical properties of the step structures based on a low temperature expansion approach and a replica approach. the spacings between the steps vanish in the thermodynamic limit so that arbitrary small but finite variation of the field induce infinitely many level crossings in the thermodynamic limit leading to a static chaos effect which yields a self - averaging, smooth macroscopic response. we also note that there is a strong analogy between the problem of step - wise responses in glassy systems at mesoscopic scales and intermittency in turbulent flows due to shocks.
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arxiv:cond-mat/0608293
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we show that the satake - baily - borel compactification of the moduli space of lattice polarized k3 surfaces parametrizing k3 surfaces of degree 2 with four rational double points of type $ d _ 4 $ is the projective 3 - space. we also show that the corresponding graded ring of automorphic forms is generated by four elements of weight 2 and one element of weight 11 with one relation of weight 22.
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arxiv:2403.04177
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preference - based reinforcement learning ( rl ) has emerged as a new field in robot learning, where humans play a pivotal role in shaping robot behavior by expressing preferences on different sequences of state - action pairs. however, formulating realistic policies for robots demands responses from humans to an extensive array of queries. in this work, we approach the sample - efficiency challenge by expanding the information collected per query to contain both preferences and optional text prompting. to accomplish this, we leverage the zero - shot capabilities of a large language model ( llm ) to reason from the text provided by humans. to accommodate the additional query information, we reformulate the reward learning objectives to contain flexible highlights - - state - action pairs that contain relatively high information and are related to the features processed in a zero - shot fashion from a pretrained llm. in both a simulated scenario and a user study, we reveal the effectiveness of our work by analyzing the feedback and its implications. additionally, the collective feedback collected serves to train a robot on socially compliant trajectories in a simulated social navigation landscape. we provide video examples of the trained policies at https : / / sites. google. com / view / rl - predilect
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arxiv:2402.15420
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we introduce so - called functional input neural networks defined on a possibly infinite dimensional weighted space with values also in a possibly infinite dimensional output space. to this end, we use an additive family to map the input weighted space to the hidden layer, on which a non - linear scalar activation function is applied to each neuron, and finally return the output via some linear readouts. relying on stone - weierstrass theorems on weighted spaces, we can prove a global universal approximation result on weighted spaces for continuous functions going beyond the usual approximation on compact sets. this then applies in particular to approximation of ( non - anticipative ) path space functionals via functional input neural networks. as a further application of the weighted stone - weierstrass theorem we prove a global universal approximation result for linear functions of the signature. we also introduce the viewpoint of gaussian process regression in this setting and emphasize that the reproducing kernel hilbert space of the signature kernels are cameron - martin spaces of certain gaussian processes. this paves a way towards uncertainty quantification for signature kernel regression.
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arxiv:2306.03303
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in the context of the supersymmetrized seesaw mechanism embedded in the minimal supersymmetric standard model ( mssm ), complex neutrino yukawa couplings can induce electric dipole moments ( edms ) for the charged leptons, providing an additional route to seesaw parameters. however, the complex neutrino yukawa matrix is not the only possible source of cp violation. even in the framework of constrained mssm ( cmssm ), there are additional sources, usually attributed to the phases of the trilinear soft supersymmetry breaking couplings and the mu - term, which contribute not only to the electron edm but also to the edms of neutron and heavy nuclei. in this work, by combining bounds on various edms, we analyze how the sources of cp violation can be discriminated by the present and planned edm experiments.
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arxiv:hep-ph/0508236
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a direct method is proposed for reconstruction of the effective atomic number by means of multi - energy radiography of the material. the accuracy of the method is up to 95 %. advantages over conventional radiographic methods, which ensure accuracy of just about 50 %, are discussed. a physical model has been constructed, and general expressions have been obtained for description of the effective atomic number in a two - energy monitoring scheme. a universal dependence has been predicted for the effective atomic number as a function of relative ( two - energy ) radiographic reflex. the established theoretical law is confirmed by the experimental data presented. the proposed development can find multiple applications in non - destructive testing and related fields, including those in the civil sphere as well as anti - terrorist activities.
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arxiv:physics/0310118
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in this paper we will give necessary and sufficient conditions for the operator $ t _ \ nu ^ s $ to be in the symmetrically normed ideal $ \ mathcal { c } _ \ phi $ for an arbitrary symmetric norming function $ \ phi $ where $ t _ \ nu $ is the toeplitz operator on the generalized fock space ( also known as the generalized bargmann - fock space ) with a positive measure symbol $ \ nu $ and $ 0 < s \ leq 1 $.
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arxiv:1410.6083
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in this paper, we introduce a conduction model of fermi particles on a finite sample, and investigate the asymptotic behavior of stationary current for large sample size. in our model a sample is described by a one - dimensional finite lattice on which fermi particles injected at both ends move under various potentials and noise from the environment. we obtain a simple current formula. the formula has broad applicability and is used to study various potentials. when the noise is absent, it provides the asymptotic behavior of the current in terms of a transfer matrix. in particular, for dynamically defined potential cases, a relation between exponential decay of the current and the lyapunov exponent of a relevant transfer matrix is obtained. for example, it is shown that the current decays exponentially for the anderson model. on the other hand, when the noise exists but the potential does not, an explicit form of the current is obtained, which scales as 1 / n for large sample size n. moreover, we provide an extension to higher dimensional systems. for a three - dimensional case, it is shown that the current increases in proportion to cross section and decreases in inverse proportion to the length of the sample.
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arxiv:2009.10943
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two - stage wireless power receivers, which typically include an ac - dc diode rectifier and a dc - dc regulator, are popular solutions in low - power wireless power transfer applications. however, the interaction between the rectifier and the regulator may introduce beat frequency oscillation on both the dc - link and output capacitors. in this paper, the cause of the beat frequency oscillation and its related issues are investigated with the corresponding design solution on alleviating the oscillation discussed. theoretical and experimental results verifying the presence of beat frequency oscillation in the two - stage wireless receiver system are provided. our study shows that the beat frequency oscillation can be significantly alleviated if appropriate design solutions are applied.
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arxiv:2004.13420
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federated learning is machine learning in the context of a network of clients whilst maintaining data residency and / or privacy constraints. community detection is the unsupervised discovery of clusters of nodes within graph - structured data. the intersection of these two fields uncovers much opportunity, but also challenge. for example, it adds complexity due to missing connectivity information between privately held graphs. in this work, we explore the potential of federated community detection by conducting initial experiments across a range of existing datasets that showcase the gap in performance introduced by the distributed data. we demonstrate that isolated models would benefit from collaboration establishing a framework for investigating challenges within this domain. the intricacies of these research frontiers are discussed alongside proposed solutions to these issues.
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arxiv:2312.09023
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the present article is a brief informal survey of computability logic - - - the game - semantically conceived formal theory of computational resources and tasks. this relatively young nonclassical logic is a conservative extension of classical first order logic but is much more expressive than the latter, yielding a wide range of new potential application areas. in a reasonable ( even if not strict ) sense the same holds for intuitionistic and linear logics, which allows us to say that col reconciles and unifies the three traditions of logical thought ( and beyond ) on the basis of its natural and " universal " game semantics. a comprehensive online survey of the subject can be found at http : / / www. csc. villanova. edu / ~ japaridz / cl /.
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arxiv:1902.05172
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the time slice axiom states that the observables which can be measured within an arbitrarily small time interval suffice to predict all other observables. while well known for free field theories where the validity of the time slice axiom is an immediate consequence of the field equation it was not known whether it also holds in generic interacting theories, the only exception being certain superrenormalizable models in 2 dimensions. in this paper we prove that the time slice axiom holds at least for scalar field theories within formal renormalized perturbation theory.
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arxiv:0802.1642
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transversal gates on quantum error correction codes have been a promising approach for fault - tolerant quantum computing, but are limited by the eastin - knill no - go theorem. existing solutions like gate teleportation and magic state distillation are resource - intensive. we present a measurement - free code - switching protocol for universal quantum computation, switching between a stabiliser code for transversal cliffords and a permutation - invariant code for transversal non - cliffords that are logical $ z $ rotations for any rational multiple of $ \ pi $. the novel non - clifford gates enabled by this code - switching protocol enable implementation of a universal gate set more efficient than the clifford $ + t $ gate set. to achieve this, we present a protocol for performing controlled - nots between the codes using near - term quantum control operations that employ a catalytic bosonic mode.
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arxiv:2411.13142
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by analogy with methods of spivak, there is a realization functor which takes a persistence diagram $ y $ in simplicial sets to an extended pseudo - metric space ( or ep - metric space ) $ re ( y ) $. the functor $ re $ has a right adjoint, called the singular functor, which takes an ep - metric space $ z $ to a persistence diagram $ s ( z ) $. we give an explicit description of $ re ( y ) $, and show that it depends only on the $ 1 $ - skeleton $ sk _ { 1 } y $ of $ y $. if $ x $ is a totally ordered ep - metric space, then there is an isomorphism $ re ( v _ { \ ast } ( x ) ) \ cong x $, between the realization of the vietoris - rips diagram $ v _ { \ ast } ( x ) $ and the ep - metric space $ x $. the persistence diagrams $ v _ { \ ast } ( x ) $ and $ s ( x ) $ are sectionwise equivalent for all such $ x $.
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arxiv:2012.09026
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we clarify the conditions of the cosmic quantum chromodynamics ( qcd ) first - order phase transition in the early universe by carefully distinguishing the chiral and deconfinement phase transitions. while the chiral one with light quarks at zero chemical potential is unlikely to be first order based on the recent lattice qcd calculations, the latter one can be naturally extended with one extra rolling scalar to be first order. the argument is also valid for the dark qcd theory with arbitrary $ n _ c $ with a wide range of phase transition temperatures, which can be from hundreds of mev up to beyond tev. notably, here we derive the general formula for the deconfinement phase transition potential of su ( $ n _ c $ ) gauge theory characterized by the polyakov loop. with the effective potential in hand, the gravitational wave spectrum is then determined via the sound shell model, which then enables us to give for the first time the quantitative analysis of the gravitational wave signals coming from the qcd deconfinement phase transition and awaits the check from future space interferometers.
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arxiv:2405.00490
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the goal of this modern presentation, followed by an english translation from the german, is to make available some parts of lie ' s very systematic mathematical thought which deserve to join the contemporary literature, and above all also, to be read.
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arxiv:1003.3202
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we study the $ \ eta \ to 2 \ gamma $ decay using an extended three - flavor nambu - jona - lasinio model that includes the ' t ~ hooft instanton induced interaction. the $ \ eta $ meson mass and the $ \ eta \ to 2 \ gamma $ decay width are reproduced simultaneously with a rather strong instanton induced interaction. the calculated $ \ eta $ decay constant is $ f _ \ eta = 2. 23 f _ \ pi $ and it suggests that the $ \ eta $ meson is no longer the goldstone boson.
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arxiv:hep-ph/9506254
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the structures in target space geometry that correspond to conformally invariant boundary conditions in wzw theories are determined both by studying the scattering of closed string states and by investigating the algebra of open string vertex operators. in the limit of large level, we find branes whose world volume is a regular conjugacy class or, in the case of symmetry breaking boundary conditions, a ` twined ' version thereof. in particular, in this limit one recovers the commutative algebra of functions over the brane world volume, and open strings connecting different branes disappear. at finite level, the branes get smeared out, yet their approximate localization at ( twined ) conjugacy classes can be detected unambiguously. as a by - product, it is demonstrated how the pentagon identity and tetrahedral symmetry imply that in any rational conformal field theory the structure constants of the algebra of boundary operators coincide with specific entries of fusing matrices.
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arxiv:hep-th/9909030
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the pitfalls of centralized social networks, such as facebook and twitter / x, have led to concerns about control, transparency, and accountability. decentralized social networks have emerged as a result with the goal of empowering users. these decentralized approaches come with their own tradeoffs, and therefore multiple architectures exist. in this paper, we conduct the first large - scale analysis of bluesky, a prominent decentralized microblogging platform. in contrast to alternative approaches ( e. g. mastodon ), bluesky decomposes and opens the key functions of the platform into subcomponents that can be provided by third party stakeholders. we collect a comprehensive dataset covering all the key elements of bluesky, study user activity and assess the diversity of providers for each sub - components.
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arxiv:2408.12449
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motivated by many recent experimental studies of non - classical rotational inertia ( ncri ) in superfluid and supersolid samples, we present a study of the hydrodynamics of a superfluid confined in the two - dimensional region ( equivalent to a long cylinder ) between two concentric arcs of radii $ b $ and $ a $ ( $ b < a $ ) subtending an angle $ \ beta $, with $ 0 \ le \ beta \ le 2 \ pi $. the case $ \ beta = 2 \ pi $ corresponds to a blocked ring. we discuss the methodology to compute the ncri effects, and calculate these effects both for small angular velocities, when no vortices are present, and in the presence of a vortex. we find that, for a blocked ring, the ncri effect is small, and that therefore there will be a large discontinuity in the moment of inertia associated with blocking or unblocking circular paths. for blocked wedges ( $ b = 0 $ ) with $ \ beta > \ pi $, we find an unexpected divergence of the velocity at the origin, which implies the presence of either a region of normal fluid or a vortex for { \ it any } nonzero value of the angular velocity. implications of our results for experiments on " supersolid " behavior in solid $ ^ 4 { \ rm he } $ are discussed. a number of mathematical issues are pointed out and resolved.
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arxiv:0812.3112
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methods for measuring the absolute center - of - mass energy using dileptons from e $ ^ { + } $ e $ ^ { - } $ collision events are further developed with an emphasis on accelerator, detector, and physics limitations. we discuss two main estimators, the lepton momentum - based center - of - mass energy estimator, $ \ sqrt { s } _ { p } $, discussed previously, and new estimators for the electron and positron colliding beam energies, denoted $ e ^ { \ text { c } } _ { - } $ and $ e ^ { \ text { c } } _ { + } $. in this work we focus on the underlying limitations from beam energy spread, detector resolution, and the modeling of higher - order qed radiative corrections associated with photon emissions originating from initial - state - radiation ( isr ), final - state - radiation ( fsr ), and their interference. we study the consequent implications for the potential of these methods at center - of - mass energies ranging from 90 gev to 1 tev relevant to a number of potential accelerator realizations in the context of measurements of masses of the z, w, h, top quark, and new particles. the statistical importance of the bhabha channel for higgs factories is noted. additional extensive work on improving the modeling of the luminosity spectrum including the use of copulas is also reported.
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arxiv:2308.10414
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using the functional renormalization group approach we construct effective quantum spacetime geometries by self - consistently deforming the classical schwarzschild - de sitter black - hole solution. this involves studying how quantum corrections, driven by the running of the newton ' s and cosmological constants modify the solution across the infrared and ultraviolet regimes. we show that these quantum modifications replace the schwarzschild singularity with a milder conical one. moreover, two new features emerge in the ultraviolet regime. first, we identify a phase transition between anti - de sitter / de sitter spacetime occurring when the object ' s mass exceeds a first critical threshold. second, we predict the formation of horizons once the object ' s mass exceeds a second threshold. both thresholds are of the order of the planck mass. finally, we investigate the role of the anomalous dimension in the conformal sector of the theory.
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arxiv:2410.16866
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we consider a su - schrieffer - heeger model in the assisted hopping limit, where direct electron hopping is subdominant. at fixed electron - phonon coupling and in the absence of coulomb interactions, the model shows a deconfined quantum critical point ( dqcp ) between a $ ( \ pi, 0 ) $ valence bond solid in the adiabatic limit and a quantum antiferromagnetic ( afm ) phase at high phonon frequencies. here, we show that by adding terms to the model that reinforce the afm phase, thereby lowering the critical phonon frequency, the quantum phase transition becomes strongly first order. our results do not depend on the symmetry of the model. in fact, adding a hubbard - $ u $ term to the model lowers the o ( 4 ) symmetry of the model to su ( 2 ) such that the dqcp we observe has the same symmetries as other models that account for similar quantum phase transitions.
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arxiv:2412.17215
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we obtain information about the magnetic flux present in the quiet sun by comparing radiative mhd simulations with hinode / sp observations, with particular emphasis on the role of surface dynamo action. simulation runs with different magnetic reynolds numbers ( rm ) are used together with observations at different heliocentric angles with different levels of noise. the results show that simulations with an imposed mixed - polarity field and rm below the threshold for dynamo action reproduce the observed vertical flux density, but do not display a sufficiently high horizontal flux density. surface dynamo simulations at the highest rm feasible at the moment yield a ratio of the horizontal and vertical flux density consistent with observational results, but the overall amplitudes are too low. based on the properties of the local dynamo simulations, a tentative scaling of the magnetic field strength by a factor 2 - 3 reproduces the signal observed in the internetwork regions. we find an agreement with observations at different heliocentric angles. the mean field strength in internetwork, implied by our analysis, is roughly 170 g at the optical depth unity. our study shows that surface dynamo could be responsible for most of the magnetic flux in the quiet sun outside the network given that the extrapolation to higher rm is valid.
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arxiv:1001.2183
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a metric graph is a geometric realization of a finite graph by identifying each edge with a real interval. a divisor on a metric graph $ \ gamma $ is an element of the free abelian group on $ \ gamma $. the rank of a divisor on a metric graph is a concept appearing in the riemann - roch theorem for metric graphs ( or tropical curves ) due to gathmann and kerber, and mikhalkin and zharkov. we define a \ emph { rank - determining set } of a metric graph $ \ gamma $ to be a subset $ a $ of $ \ gamma $ such that the rank of a divisor $ d $ on $ \ gamma $ is always equal to the rank of $ d $ restricted on $ a $. we show constructively in this paper that there exist finite rank - determining sets. in addition, we investigate the properties of rank - determining sets in general and formulate a criterion for rank - determining sets. our analysis is a based on an algorithm to derive the $ v _ 0 $ - reduced divisor from any effective divisor in the same linear system.
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arxiv:0906.2807
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we study the asymptotic behaviour of a properly normalized time changed wiener processes. the time change reflects the fact that we consider the laplace operator ( which generates a wiener process ) multiplied by a possibly degenerate state - space dependent intensity $ \ lambda ( x ) $. applying a functional limit theorem for the superposition of stochastic processes, we prove functional limit theorems for the normalized time changed wiener process. the normalization depends on the asymptotic behaviour of the intensity function $ \ lambda $. one of the possible limits is a skew brownian motion.
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arxiv:2005.04122
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lines and right edges with dashed lines. the original knot diagram is the medial graph of this new plane graph, with the type of each crossing determined by the sign of the corresponding edge. changing the sign of every edge corresponds to reflecting the knot in a mirror. = = = linkless and knotless embedding = = = in two dimensions, only the planar graphs may be embedded into the euclidean plane without crossings, but in three dimensions, any undirected graph may be embedded into space without crossings. however, a spatial analogue of the planar graphs is provided by the graphs with linkless embeddings and knotless embeddings. a linkless embedding is an embedding of the graph with the property that any two cycles are unlinked ; a knotless embedding is an embedding of the graph with the property that any single cycle is unknotted. the graphs that have linkless embeddings have a forbidden graph characterization involving the petersen family, a set of seven graphs that are intrinsically linked : no matter how they are embedded, some two cycles will be linked with each other. a full characterization of the graphs with knotless embeddings is not known, but the complete graph k7 is one of the minimal forbidden graphs for knotless embedding : no matter how k7 is embedded, it will contain a cycle that forms a trefoil knot. = = generalization = = in contemporary mathematics the term knot is sometimes used to describe a more general phenomenon related to embeddings. given a manifold m with a submanifold n, one sometimes says n can be knotted in m if there exists an embedding of n in m which is not isotopic to n. traditional knots form the case where n = s1 and m = r3 or m = s3. the schoenflies theorem states that the circle does not knot in the 2 - sphere : every topological circle in the 2 - sphere is isotopic to a geometric circle. alexander ' s theorem states that the 2 - sphere does not smoothly ( or pl or tame topologically ) knot in the 3 - sphere. in the tame topological category, it ' s known that the n - sphere does not knot in the n + 1 - sphere for all n. this is a theorem of morton brown, barry mazur, and marston morse. the alexander horned sphere is an example of a knotted 2 - sphere in the 3 - sphere which is not
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https://en.wikipedia.org/wiki/Knot_(mathematics)
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signal maps are essential for the planning and operation of cellular networks. however, the measurements needed to create such maps are expensive, often biased, not always reflecting the metrics of interest, and posing privacy risks. in this paper, we develop a unified framework for predicting cellular signal maps from limited measurements. our framework builds on a state - of - the - art random - forest predictor, or any other base predictor. we propose and combine three mechanisms that deal with the fact that not all measurements are equally important for a particular prediction task. first, we design quality - of - service functions ( $ q $ ), including signal strength ( rsrp ) but also other metrics of interest to operators, i. e., coverage and call drop probability. by implicitly altering the loss function employed in learning, quality functions can also improve prediction for rsrp itself where it matters ( e. g., mse reduction up to 27 % in the low signal strength regime, where errors are critical ). second, we introduce weight functions ( $ w $ ) to specify the relative importance of prediction at different locations and other parts of the feature space. we propose re - weighting based on importance sampling to obtain unbiased estimators when the sampling and target distributions are different. this yields improvements up to 20 % for targets based on spatially uniform loss or losses based on user population density. third, we apply the data shapley framework for the first time in this context : to assign values ( $ \ phi $ ) to individual measurement points, which capture the importance of their contribution to the prediction task. this improves prediction ( e. g., from 64 % to 94 % in recall for coverage loss ) by removing points with negative values, and can also enable data minimization. we evaluate our methods and demonstrate significant improvement in prediction performance, using several real - world datasets.
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arxiv:2202.03679
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we prove a sharp, dimension - free stability result for the classical logarithmic sobolev inequality for a two parameter family of functions. roughly speaking, our family consists of a certain class of log $ c ^ { 1, 1 } $ functions. moreover, we show how to enlarge this space at the expense of the dimensionless constant and the sharp exponent. as an application we obtain new bounds on the entropy.
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arxiv:1302.4910
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in this book, for the first time we introduce the notion of neutrosophic algebraic structures for groups, loops, semigroups and groupoids ; and also their neutrosophic n - algebraic structures. one is fully aware of the fact that many classical theorems like lagrange, sylow and cauchy have been studied only in the context of finite groups. here we try to shift the paradigm by studying and introducing these theorems to neutrosophic semigroups, neutrosophic groupoids, and neutrosophic loops. this book has seven chapters. chapter one provides several basic notions to make this book self - contained. chapter two introduces neutrosophic groups and neutrosophic n - groups and gives several examples. the third chapter deals with neutrosophic semigroups and neutrosophic n - semigroups, giving several interesting results. chapter four introduces neutrosophic loops and neutrosophic n - loops. we introduce several new, related definitions. in fact we construct a new class of neutrosophic loops using modulo integer z _ n, n > 3, where n is odd. several properties of these structures are proved using number theoretic techniques. chapter five just introduces the concept of neutrosophic groupoids and neutrosophic n - groupoids. sixth chapter innovatively gives mixed neutrosophic structures and their duals. the final chapter gives problems for the interested reader to solve.
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arxiv:math/0603581
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this paper applies the hotelling model to the context of exhaustible human resources in china. we find that over - exploitation of human resources occurs under conditions of restricted population mobility, rigid wage levels, and increased foreign trade demand elasticity. conversely, the existence of technological replacements for human resources or improvements in the utilization rate of human resources leads to conservation. our analysis provides practical insights for policy - making towards sustainable development.
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arxiv:2308.07154
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distributed systems infrastructure ( dsi ) is mongodb ' s framework for running fully automated system performance tests in our continuous integration ( ci ) environment. to run in ci it needs to automate everything end - to - end : provisioning and deploying multi - node clusters, executing tests, tuning the system for repeatable results, and collecting and analyzing the results. today dsi is mongodb ' s most used and most useful performance testing tool. it runs almost 200 different benchmarks in daily ci, and we also use it for manual performance investigations. as we can alert the responsible engineer in a timely fashion, all but one of the major regressions were fixed before the 4. 2. 0 release. we are also able to catch net new improvements, of which dsi caught 17. we open sourced dsi in march 2020.
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arxiv:2004.08425
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speech is the most natural way of expressing ourselves as humans. identifying emotion from speech is a nontrivial task due to the ambiguous definition of emotion itself. speaker emotion recognition ( ser ) is essential for understanding human emotional behavior. the ser task is challenging due to the variety of speakers, background noise, complexity of emotions, and speaking styles. it has many applications in education, healthcare, customer service, and human - computer interaction ( hci ). previously, conventional machine learning methods such as svm, hmm, and knn have been used for the ser task. in recent years, deep learning methods have become popular, with convolutional neural networks and recurrent neural networks being used for ser tasks. the input of these methods is mostly spectrograms and hand - crafted features. in this work, we study the use of self - supervised transformer - based models, wav2vec2 and hubert, to determine the emotion of speakers from their voice. the models automatically extract features from raw audio signals, which are then used for the classification task. the proposed solution is evaluated on reputable datasets, including ravdess, shemo, savee, aesdd, and emo - db. the results show the effectiveness of the proposed method on different datasets. moreover, the model has been used for real - world applications like call center conversations, and the results demonstrate that the model accurately predicts emotions.
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arxiv:2411.02964
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an outstanding problem in the study of networks of heterogeneous dynamical units concerns the development of rigorous methods to probe the stability of synchronous states when the differences between the units are not small. here, we address this problem by presenting a generalization of the master stability formalism that can be applied to heterogeneous oscillators with large mismatches. our approach is based on the simultaneous block diagonalization of the matrix terms in the variational equation, and it leads to dimension reduction that simplifies the original equation significantly. this new formalism allows the systematic investigation of scenarios in which the oscillators need to be nonidentical in order to reach an identical state, where all oscillators are completely synchronized. in the case of networks of identically coupled oscillators, this corresponds to breaking the symmetry of the system as a means to preserve the symmetry of the dynamical state - - - a recently discovered effect termed asymmetry - induced synchronization ( aisync ). our framework enables us to identify communication delay as a new and potentially common mechanism giving rise to aisync, which we demonstrate using networks of delay - coupled stuart - landau oscillators. the results also have potential implications for control, as they reveal oscillator heterogeneity as an attribute that may be manipulated to enhance the stability of synchronous states.
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arxiv:1712.03245
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we show that single and multislit experiments involving matter waves may be constructed to assess correlations between the position and momentum of a single free particle. these correlations give rise to position dependent phases which develop dynamically and may play an important role in the interference patterns. for large enough transverse coherence lenght such interference patterns are noticeably different from those of a classical dispersion free wave.
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arxiv:quant-ph/0512076
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the strongly lensed supernova ( sn ) encore at a redshift of $ z = 1. 949 $, discovered behind the galaxy cluster macs j0138 $ - $ 2155 at $ z = 0. 336 $, provides a rare opportunity for time - delay cosmography and studies of the sn host galaxy, where previously another sn, called sn requiem, had appeared. to enable these studies, we combine new james webb space telescope ( jwst ) imaging, archival hubble space telescope ( hst ) imaging, and new very large telescope ( vlt ) spectroscopic data to construct state - of - the - art lens mass models that are composed of cluster dark - matter ( dm ) halos and galaxies. we determine the photometric and structural parameters of the galaxies across six jwst and five hst filters. we use the color - magnitude and color - color relations of spectroscopically - confirmed cluster members to select additional cluster members, identifying a total of 84 galaxies belonging to the galaxy cluster. we construct seven different mass models using a variety of dm halo mass profiles, and explore both multi - plane and approximate single - plane lens models. as constraints, we use the observed positions of 23 multiple images from eight multiply lensed sources at four distinct spectroscopic redshifts. in addition, we use stellar velocity dispersion measurements to obtain priors on the galaxy mass distributions. we find that six of the seven models fit well to the observed image positions. mass models with cored - isothermal dm profiles fit well to the observations, whereas the mass model with a navarro - frenk - white cluster dm profile has an image - position $ \ chi ^ 2 $ value that is four times higher. we build our ultimate model by combining four multi - lens - plane mass models and predict the image positions and magnifications of sn encore and sn requiem. our work lays the foundation for building state - of - the - art mass models of the cluster for future cosmological analysis and sn host galaxy studies.
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arxiv:2503.09718
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revisiting canonical integration of the classical solid near a uniform rotation, canonical action angle coordinates, hyperbolic and elliptic, are constructed in terms of various power series with coefficients which are polynomials in a variable $ r ^ 2 $ depending on the inertia moments. normal forms are derived via the analysis of a relative cohomology problem and shown to be obtainable without the use of ellitptic integrals ( unlike the derivation of the action - angles ). results and conjectures also emerge about the properties of the above polynomials and the location of their roots. in particular a class of polynomials with all roots on the unit circle arises.
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arxiv:1202.2741
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urban area - of - interest ( aoi ) refers to an integrated urban functional zone with defined polygonal boundaries. the rapid development of urban commerce has led to increasing demands for highly accurate and timely aoi data. however, existing research primarily focuses on coarse - grained functional zones for urban planning or regional economic analysis, and often neglects the expiration of aoi in the real world. they fail to fulfill the precision demands of mobile internet online - to - offline ( o2o ) businesses. these businesses require accuracy down to a specific community, school, or hospital. in this paper, we propose a comprehensive end - to - end multimodal deep learning framework designed for simultaneously detecting accurate aoi boundaries and validating the reliability of aoi by leveraging remote sensing imagery coupled with geographical prior, titled aoitr. unlike conventional aoi generation methods, such as the road - cut method that segments road networks at various levels, our approach diverges from semantic segmentation algorithms that depend on pixel - level classification. instead, our aoitr begins by selecting a point - of - interest ( poi ) of specific category, and uses it to retrieve corresponding remote sensing imagery and geographical prior such as entrance pois and road nodes. this information helps to build a multimodal detection model based on transformer encoder - decoder architecture to regress the aoi polygon. additionally, we utilize the dynamic features from human mobility, nearby pois, and logistics addresses for aoi reliability evaluation via a cascaded network module. the experimental results reveal that our algorithm achieves a significant improvement on intersection over union ( iou ) metric, surpassing previous methods by a large margin.
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arxiv:2401.06550
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a recent paper by v. v. demjanov in physics letters a reported a formula that relates the magnitude of michelson interferometer fringe shifts to refractive index and absolute velocity. we show here that relativistic corrections to the sellmeier equation allow an alternative derivation of the formula.
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arxiv:1003.2035
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airline crew pairing optimization ( cpo ) aims at generating a set of legal flight sequences ( crew pairings ), to cover an airline ' s flight schedule, at minimum cost. it is usually performed using column generation ( cg ), a mathematical programming technique for guided search - space exploration. cg exploits the interdependencies between the current and the preceding cg - iteration for generating new variables ( pairings ) during the optimization - search. however, with the unprecedented scale and complexity of the emergent flight networks, it has become imperative to learn higher - order interdependencies among the flight - connection graphs, and utilize those to enhance the efficacy of the cpo. in first of its kind and what marks a significant departure from the state - of - the - art, this paper proposes a novel adaptation of the variational graph auto - encoder for learning plausible combinatorial patterns among the flight - connection data obtained through the search - space exploration by an airline crew pairing optimizer, aircrop ( developed by the authors and validated by the research consortium ' s industrial sponsor, ge aviation ). the resulting flight - connection predictions are combined on - the - fly using a novel heuristic to generate new pairings for the optimizer. the utility of the proposed approach is demonstrated on large - scale ( over 4200 flights ), real - world, complex flight - networks of us - based airlines, characterized by multiple hub - and - spoke subnetworks and several crew bases.
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arxiv:2004.13714
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we study the class of 3 - dimensional nonlinear 2 - hessian equations mentioned in the text. we perform preliminary group classification on 2 - hessian equation. in fact, we find additional equivalence transformation on the space ( x, y, z, u, f ), with the aid of a method, then we take their projections on the space ( x, y, z, f ), so we prove an optimal system of one - dimensional lie sub algebras of this equation is generated by a1 to a12, which introduced in theorem 2, ultimately, a number of new interesting nonlinear invariant models are obtained which have non - trivial in variance algebras. the result of these works is a wide class of equations which summarized in table. so at the end of this work, some exact solutions of 2 - hessian equation are presented. the paper is one of the few applications of an algebraic approach to the group classification using lie method.
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arxiv:1902.02702
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the dynamics of red blood cells ( rbcs ) in oscillatory shear flow was studied using differential equations of three variables : a shape parameter, the inclination angle $ \ theta $, and phase angle $ \ phi $ of the membrane rotation. in steady shear flow, three types of dynamics occur depending on the shear rate and viscosity ratio. i ) tank - treading ( tt ) : $ \ phi $ rotates while the shape and $ \ theta $ oscillate. ii ) tumbling ( tb ) : $ \ theta $ rotates while the shape and $ \ phi $ oscillate. iii ) intermediate motion : both $ \ phi $ and $ \ theta $ rotate synchronously or intermittently. in oscillatory shear flow, rbcs show various dynamics based on these three motions. for a low shear frequency with zero mean shear rate, a limit - cycle oscillation occurs, based on the tt or tb rotation at a high or low shear amplitude, respectively. this tt - based oscillation well explains recent experiments. in the middle shear amplitude, rbcs show an intermittent or synchronized oscillation. as shear frequency increases, the vesicle oscillation becomes delayed with respect to the shear oscillation. at a high frequency, multiple limit - cycle oscillations coexist. for a high mean shear rate with small shear oscillation, the shape and $ \ theta $ oscillate in the tt motion but only one attractor exists even at high shear frequencies. the measurement of these oscillatory modes is a promising tool for quantifying the viscoelasticity of rbcs and synthetic capsules.
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arxiv:0903.0038
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we construct axisymmetric mass models for dwarf spheroidal ( dsph ) galaxies in the milky way to obtain plausible limits on the non - spherical structure of their dark halos. this is motivated by the fact that the observed luminous parts of the dsphs are actually non - spherical and cold dark matter ( cdm ) models predict non - spherical virialized dark halos. our models consider velocity anisotropy of stars $ \ bar { v ^ 2 _ r } / \ bar { v ^ 2 _ { \ phi } } $, which can vary with the adopted cylindrical coordinates under the assumption $ \ bar { v ^ 2 _ z } = \ bar { v ^ 2 _ r } $ for simplicity, and also include an inclination of the system as a fitting parameter to explain the observed line - of - sight velocity dispersion profile. applying these models to six of the bright dsphs in the milky way, we find that the best - fitting cases for most of the dsphs yield oblate and flattened dark halos, irrespective of assumed density profiles in their central parts. we also find that the total mass of the dsphs enclosed within a spheroid with major - axis length of 300 pc varies from $ 10 ^ 6m _ { \ odot } $ to $ 10 ^ 7m _ { \ odot } $, contrary to the conclusion from spherical models. this suggests the importance of considering shapes of dark halos in mass models of the dsphs. it is also found that dark halos of the galactic dsphs may be more flattened than n - body predictions, thereby implying our yet incomplete understanding of baryonic and / or non - baryonic dark matter physics in dwarf galaxy scales.
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arxiv:1206.3888
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be explained by the conversion of c $ _ 2 $ h to other species ( e. g. co ) when the clump temperature rises, especially after the ignition of a hot molecular core in the clump. the decrease of $ [ { \ rm hn ^ { 13 } c } ] / [ { \ rm h ^ { 13 } cn } ] $ as the clump evolves is also likely to reflect the increase in the clump temperature, which leads to an enhanced formation of hcn and its $ ^ { 13 } $ c isotopologue.
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arxiv:2005.08250
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the notion of strong nonlocality, which refers to local irreducibility of a set of orthogonal multipartite quantum states across each bipartition of the subsystems, was put forward by halder et al. in [ phys. rev. lett. 122, 040403 ( 2019 ) ]. here, we show the existence of three orthogonal quantum states in ( c ^ 2 ) ^ { \ otimes n } that cannot be perfectly distinguished locally across any bipartition of the subsystems. specifically, all these three states are genuinely entangled, among which two are the n - qubit ghz pairs. since any three locally indistinguishable states are always locally irreducible, the three n - partite orthogonal states we present are strongly nonlocal. thus, the caridnality of strongly nonlocal sets here is dramatically smaller than all known ones.
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arxiv:2403.10969
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we show that given a graph g we can cmso - transduce its modular decomposition, its split decomposition and its bi - join decomposition. this improves results by courcelle [ logical methods in computer science, 2006 ] who gave such transductions using order - invariant mso, a strictly more expressive logic than cmso. our methods more generally yield cmso [ 2 ] - transductions of the canonical decomposition of weakly - partitive set systems and weakly - bipartitive systems of bipartitions.
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arxiv:2412.04970
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let $ \ mathcal { h } _ 2 $ be the lie algebra of polynomial hamiltonian vector fields on the symplectic plane. let $ x $ be the moduli space of stable higgs bundles of fixed relatively prime rank and degree, or more generally the moduli space of stable parabolic higgs bundles of arbitrary rank and degree for a generic stability condition. let $ h ^ * ( x ) $ be the cohomology with rational coefficients. using the operations of cup - product by tautological classes and hecke correspondences we construct an action of $ \ mathcal { h } _ 2 $ on $ h ^ * ( x ) [ x, y ] $, where $ x $ and $ y $ are formal variables. we show that the perverse filtration on $ h ^ * ( x ) $ coincides with the filtration canonically associated to $ \ mathfrak { sl } _ 2 \ subset \ mathcal { h } _ 2 $ and deduce the $ p = w $ conjecture of de cataldo - hausel - migliorini.
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arxiv:2209.05429
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we present setexpander, a corpus - based system for expanding a seed set of terms into amore complete set of terms that belong to the same semantic class. setexpander implements an iterative end - to - end workflow. it enables users to easily select a seed set of terms, expand it, view the expanded set, validate it, re - expand the validated set and store it, thus simplifying the extraction of domain - specific fine - grained semantic classes. setexpander has been used successfully in real - life use cases including integration into an automated recruitment system and an issues and defects resolution system. a video demo of setexpander is available at https : / / drive. google. com / open? id = 1e545bb87autsch36djnjhmq3hwfsd1rv ( some images were blurred for privacy reasons )
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arxiv:1808.08953
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constructing matrix product operators ( mpo ) is at the core of the modern density matrix renormalization group ( dmrg ) and its time dependent formulation. for dmrg to be conveniently used in different problems described by different hamiltonians, in this work we propose a new generic algorithm to construct the mpo of an arbitrary operator with a sum - of - products form based on the bipartite graph theory. we show that the method has the following advantages : ( i ) it is automatic in that only the definition of the operator is required ; ( ii ) it is symbolic thus free of any numerical error ; ( iii ) the complementary operator technique can be fully employed so that the resulting mpo is globally optimal for any given order of degrees of freedom ; ( iv ) the symmetry of the system could be fully employed to reduce the dimension of mpo. to demonstrate the effectiveness of the new algorithm, the mpos of hamiltonians ranging from the prototypical spin - boson model and holstein model to the more complicated ab initio electronic hamiltonian and the anharmonic vibrational hamiltonian with sextic force field are constructed. it is found that for the former three cases, our automatic algorithm can reproduce exactly the same mpos as the optimally hand - crafted ones already known in the literature.
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arxiv:2006.02056
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we use multi - fiber spectroscopy of 12 nearby, poor groups of galaxies to address whether the groups are bound systems or chance projections of galaxies along the line - of - sight, why the members of each group have not already merged to form a single galaxy, despite the groups ' high galaxy densities, short crossing times, and likely environments for galaxy - galaxy mergers, and how galaxies might evolve in these groups, where the collisional effects of the intra - group gas and the tidal influences of the global potential are weaker than in rich clusters. we conclude the following. ( 1 ) the nine groups with diffuse x - ray emission ( cf. paper ii ) are bound systems with at least 20 - 50 group members. ( 2 ) galaxies in each x - ray - detected group have not all merged together, because a significant fraction of the group mass lies outside of the galaxies and in a common halo. ( 3 ) unlike cd galaxies in some rich clusters, the giant, brightest elliptical in each x - ray group lies in the center of the group potential, suggesting that such galaxies may form first in poor groups. ( 4 ) in some groups, the fraction and recent star formation histories of the early types are consistent with those in rich clusters, suggesting that the effects of cluster environment on these galaxies are relatively unimportant at the current epoch. ( abridged )
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arxiv:astro-ph/9708132
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this paper proposes a group membership verification protocol preventing the curious but honest server from reconstructing the enrolled signatures and inferring the identity of querying clients. the protocol quantizes the signatures into discrete embeddings, making reconstruction difficult. it also aggregates multiple embeddings into representative values, impeding identification. theoretical and experimental results show the trade - off between the security and the error rates.
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arxiv:1812.03943
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in the paper two combinations of correlators are defined in order to investigate the evolution of possible $ \ mathcal { p / cp } $ invariance violation in strong interactions with initial energy for heavy ion collisions. these combinations correspond to absolute and relative asymmetry of distribution of electrically charge particles with respect to the reaction plane in heavy ion collisions. energy dependence of the parameters was derived from data of star and alice experiments. significant decreasing both absolute and relative asymmetry is observed at energies $ \ sqrt { s _ { nn } } < 20 $ gev. this feature agrees qualitatively with other results of stage - i beam energy scan program in star experiment. general behavior of dependence of absolute asymmetry on initial energy agree reasonably with behavior of similar dependence of chern - - simons diffusion rate calculated at different values of external abelian magnetic field. the observed behavior of understudying parameters vs energy can be considered as indication on possible transition to predominance of hadronic states over quark - gluon degrees of freedom in the mixed phase created in heavy ion collisions at intermediate energies.
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arxiv:1301.0880
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one application of the cosmological gravitational lensing in general relativity is the measurement of the hubble constant h _ 0 using the time delay delta t between multiple images of lensed quasars. this method has already been applied, obtaining a value of h _ 0 compatible with that obtained from the sne 1a, but non compatible with that obtained studying the anisotropies of the cmb. this difference could be a statistical fluctuation or an indication of new physics beyond the standard model of cosmology, so it desirable to improve the precision of the measurements. at the current technological capabilities it is possible to obtain h _ 0 to a percent level uncertainty, so a more accurate theoretical model could be necessary in order to increase the precision about the determination of h _ 0. the actual formula which relates delta t with h _ 0 is approximated ; in this paper we expose a proposal to go beyond the previous analysis and, within the context of a new model, we obtain a more precise formula than that present in the literature.
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arxiv:1709.09055
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in this study, we investigated the influence of the topological defects space - time with a spiral dislocation on a spin - zero boson field by using the duffin - kemmer - petiau ( dkp ) equation. to be more specific, we solved the generalized spin - zero dkp equation in the presence of a spiral dislocation exactly. we derived the wave function and corresponding energy eigenvalues for two cases, in the absence and presence of a static potential by using analytical methods. we numerically demonstrated the effect of the spiral dislocation on the solutions.
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arxiv:2106.05791
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we introduce the notion of symplectic microfolds and symplectic micromorphisms between them. they form a monoidal category, which is a version of the " category " of symplectic manifolds and canonical relations obtained by localizing them around lagrangian submanifolds in the spirit of milnor ' s microbundles.
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arxiv:0905.3574
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we prove the existence of primitive curves and positivity of intersections of $ j $ - complex curves for lipschitz - continuous almost complex structures. these results are deduced from the comparison theorem for $ j $ - holomorphic maps in lipschitz structures, previously known for $ j $ of class $ c ^ { 1, lip } $. we also give the optimal regularity of curves in lipschitz structures. it occurs to be $ c ^ { 1, lnlip } $, i. e. the first derivatives of a $ j $ - complex curve for lipschitz $ j $ are log - lipschitz - continuous. a simple example that nothing better can be achieved is given. further we prove the genus formula for $ j $ - complex curves and determine their principal puisieux exponents ( all this for lipschitz - continuous $ j $ - s ).
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arxiv:0707.0771
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in this paper we propose an approach which demonstrates the dependence of quarkoni production on the multiplicity of the accompanying hadrons. our approach is based on the three gluons fusion mechanism, without assuming the multiplicity dependence of the saturation scale. we show, that we describe the experimental data, which has a dependence that is much steeper than the multiplicity of the hadrons.
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arxiv:2008.10911
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simple and efficient algorithm based on heuristic search by shotgun hill climbing to construct binary sequences with small peak sidelobe levels ( psl ) is suggested. the algorithm is applied for generation of binary sequences of lengths between 106 and 300. improvements are obtained in almost half of the considered lengths while for the rest of the lengths, binary sequences with the same psl values as reported in the state - of - the - art publications are found.
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arxiv:2003.07057
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we present an algorithm that computes approximate pure nash equilibria in a broad class of constraint satisfaction games that generalize the well - known cut and party affiliation games. our results improve previous ones by bhalgat et al. ~ ( ec 10 ) in terms of the obtained approximation guarantee. more importantly, our algorithm identifies a polynomially - long sequence of improvement moves from any initial state to an approximate equilibrium in these games. the existence of such short sequences is an interesting structural property which, to the best of our knowledge, was not known before. our techniques adapt and extend our previous work for congestion games ( focs 11 ) but the current analysis is considerably simpler.
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arxiv:1402.3450
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active collision avoidance system plays a crucial role in ensuring the lateral safety of autonomous vehicles, and it is primarily related to path planning and tracking control algorithms. in particular, the direct yaw - moment control ( dyc ) system can significantly improve the lateral stability of a vehicle in environments with sudden changes in road conditions. in order to apply the dyc algorithm, it is very important to accurately consider the properties of tire forces with complex nonlinearity for control to ensure the lateral stability of the vehicle. in this study, longitudinal and lateral tire forces for safety path tracking were simultaneously estimated using a long short - term memory ( lstm ) neural network based estimator. furthermore, to improve path tracking performance in case of sudden changes in road conditions, a system has been developed by combining 4 - wheel independent steering ( 4wis ) model predictive control ( mpc ) and 4 - wheel independent drive ( 4wid ) direct yaw - moment control ( dyc ). the estimation performance of the extended kalman filter ( ekf ), which are commonly used for tire force estimation, was compared. in addition, the estimated longitudinal and lateral tire forces of each wheel were applied to the proposed system, and system verification was performed through simulation using a vehicle dynamics simulator. consequently, the proposed method, the integrated path tracking algorithm with dyc and mpc using the lstm based estimator, was validated to significantly improve the vehicle stability in suddenly changing road conditions.
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arxiv:2312.07826
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we analyze spin dependent parton distributions consistent with the most recent measurements of the spin dependent deep inelastic scattering structure functions and obtained in the framework of the spin dilution model. predictions for the doubly polarised proton - proton drell - yan asymmetry, for the high $ p _ { t } $ photon production mechanism and $ j / \ psi $ excitation are calculated using these distributions and are shown to be particularly adequate to unveil the polarisation of partons in the proton.
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arxiv:hep-ph/9408363
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5g new radio paves the way for introducing novel multi - service radio resource management solutions tailored for enhanced mobile broadband and ultra - reliable low latency communication service classes. multi - channel access is a family of such multi - service solutions that enable a user equipment to aggregate radio resources from multiple sources. the objective is multi - fold ; throughput enhancement through access to a larger bandwidth, reliability improvement by increasing the diversity order and / or coordinated transmission / reception, as well as flexibility and load balancing improvement by decoupling the downlink and the uplink access points. this paper presents several multi - channel access solutions for 5g new radio multi - service scenarios. in particular, throughput enhancement and latency reduction concepts like multi - connectivity, carrier aggregation, downlink - uplink decoupled access and coordinated multi - point connectivity are discussed. moreover, novel design solutions exploiting these concepts are proposed. numerical evaluation of the introduced solutions indicates significant performance gains over state - of - the - art schemes ; for example, our proposed component carrier selection mechanism leads to a median throughput gain of up to 100 % by means of an implicit load balance. therefore, the proposed multi - channel access solutions have the potential to be key multi - service enablers for 5g new radio.
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arxiv:1902.01948
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here we present the two - photon and two - gluon decay widths of the s - wave ( $ \ eta _ { q \ in c, b } $ ) and p - wave ( $ \ chi _ { q \ in c, bj } $ ) charmonium and bottonium states and the radiative transition decay widths of $ c \ bar c $, $ b \ bar b $ and $ c \ bar b $ systems based on coulomb plus power form of the inter - quark potential ( $ cpp _ \ nu $ ) with exponent $ \ nu $. the schr $ \ ddot { o } $ dinger equation is solved numerically for different choices of the exponent $ \ nu $. we employ the masses of different states and their radial wave functions obtained from the study to compute the two - photon and two - gluon decay widths and the e1 and m1 radiative transitions. it is found that the quarkonia mass spectra and the e1 transition can be described by the same interquark model potential of the $ cpp _ \ nu $ with $ \ nu = 1. 0 $ for $ c \ bar c $ and $ \ nu = 0. 7 $ for $ b \ bar b $ systems, while the m1 transition ( at which the spin of the system changes ) and the decay rates in the annihilation channel of quarkonia are better estimated by a shallow potential with $ \ nu < 1. 0 $.
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arxiv:1001.0848
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the role of the low lying nucleon resonances beyond the $ \ delta ( 1232 ) $ in the reaction $ pp \ to pp \ pi ^ 0 $ near threshold is shown to be numerically significant by a calculation, which takes into account the pion re - scattering contribution described by chiral perturbation theory and the short - range mechanisms that are implied by the nucleon - nucleon interaction model. the intermediate n ( 1440 ) ( p $ _ { 11 } $ ) resonance is excited by the short - range exchange mechanisms, while the n ( 1535 ) ( $ s _ { 11 } $ ) and n ( 1520 ) ( $ d _ { 13 } $ ) resonances are excited by $ \ eta $ and $ \ rho $ meson exchange, respectively. the $ p _ { 11 } $ increases the calculated cross section, whereas the $ s _ { 11 } $ and $ d _ { 13 } $ resonances decrease it. the calculation takes full account of the initial and final state interactions.
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arxiv:nucl-th/9902066
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cutting planes are a crucial component of state - of - the - art mixed - integer programming solvers, with the choice of which subset of cuts to add being vital for solver performance. we propose new distance - based measures to qualify the value of a cut by quantifying the extent to which it separates relevant parts of the relaxed feasible set. for this purpose, we use the analytic centers of the relaxation polytope or of its optimal face, as well as alternative optimal solutions of the linear programming relaxation. we assess the impact of the choice of distance measure on root node performance and throughout the whole branch - and - bound tree, comparing our measures against those prevalent in the literature. finally, by a multi - output regression, we predict the relative performance of each measure, using static features readily available before the separation process. our results indicate that analytic center - based methods help to significantly reduce the number of branch - and - bound nodes needed to explore the search space and that our multiregression approach can further improve on any individual method.
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arxiv:2212.07231
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in these notes we define and study the shahidi local coefficients matrix associated with a genuine principal series representation i ( { \ sigma } ) of an n - fold cover of p - adic sl ( 2, f ) and an additive character { \ psi }. the conjugacy class of this matrix is an invariant of the inducing representation { \ sigma } and { \ psi } and its entries are linear combinations of tate or tate type { \ gamma } - factors. we relate these entries to functional equations associated with linear maps defined on the dual of the space of schwartz functions. as an application we give new formulas for the plancherel measure and use these to relate principal series representations of different coverings of sl ( 2, f ). while we do not assume that the residual characteristic of f is relatively prime to n we do assume that n is not divisible by 4.
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arxiv:1609.08122
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federated learning enables edge devices to collaboratively train a global model while maintaining data privacy by keeping data localized. however, the non - iid nature of data distribution across devices often hinders model convergence and reduces performance. in this paper, we propose a novel plugin for federated optimization techniques that approximates non - iid data distributions to iid through generative ai - enhanced data augmentation and balanced sampling strategy. key idea is to synthesize additional data for underrepresented classes on each edge device, leveraging generative ai to create a more balanced dataset across the fl network. additionally, a balanced sampling approach at the central server selectively includes only the most iid - like devices, accelerating convergence while maximizing the global model ' s performance. experimental results validate that our approach significantly improves convergence speed and robustness against data imbalance, establishing a flexible, privacy - preserving fl plugin that is applicable even in data - scarce environments.
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arxiv:2410.23824
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the screening of magnetic z ( n ) - monopoles and the associated screening length in su ( n ) gauge theories are analyzed theoretically, and computed numerically in the 3d su ( 2 ) theory. the nature of the screening excitations as well as their mass have so far remained inconclusive in the literature. here we show that the screening mass is identical to the lowest j ^ { pc } _ r = 0 ^ { + + } _ + excitation of the yang - mills hamiltonian with one compact direction with period 1 / t, the subscript r referring to parity in this direction. we extend the continuum formulation to one on the lattice, and determine the transfer matrix governing the decay of the spatial monopole correlator at any finite lattice spacing. our numerical results for su ( 2 ) for the screening mass in the dimensionally reduced ( high temperature ) theory are compatible with the 0 ^ { + + } glueball mass in 3d su ( 2 ).
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arxiv:hep-ph/0510140
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air pollution ( ap ) poses a great threat to human health, and people are paying more attention than ever to its prediction. accurate prediction of ap helps people to plan for their outdoor activities and aids protecting human health. in this paper, long - short term memory ( lstm ) recurrent neural networks ( rnns ) have been used to predict the future concentration of air pollutants ( aps ) in macau. additionally, meteorological data and data on the concentration of aps have been utilized. moreover, in macau, some air quality monitoring stations ( aqmss ) have less observed data in quantity, and, at the same time, some aqmss recorded less observed data of certain types of aps. therefore, the transfer learning and pre - trained neural networks have been employed to assist aqmss with less observed data to build a neural network with high prediction accuracy. the experimental sample covers a period longer than 12 - year and includes daily measurements from several aps as well as other more classical meteorological values. records from five stations, four out of them are aqmss and the remaining one is an automatic weather station, have been prepared from the aforesaid period and eventually underwent to computational intelligence techniques to build and extract a prediction knowledge - based system. as shown by experimentation, lstm rnns initialized with transfer learning methods have higher prediction accuracy ; it incurred shorter training time than randomly initialized recurrent neural networks.
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arxiv:2502.01654
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usually a name of the category is inherited from the name of objects. however more relevant for a category of objects and morphisms is an algebra of morphisms. therefore we prefer to say a category of graphs if every morphism is a graph. in a monoidal category every morphism can be seen as a graph, and a partial algebra of morphisms possesses a structure of an operad, operad of graphs. we consider a monoidal category of operad of graphs with underlying graphical calculus. if, in particular, there is a single generating objects, then each morphism is a bi - arity graph. the graphical calculus, multi - grafting of morphisms, is developed ab ovo. we interpret algebraic logic and predicate calculus within a monoidal category of operad of graphs, and this leads to the graphical logic. a logic based on a braided monoidal category is said to be the braided logic. we consider a braided monoidal category generated by one object. we are demonstrating how the braided logic is related to implicative algebra and to the heyting algebra ( in contrary to the boolean algebra ) and therefore must be more related to the quasigroups then to the lattices. some applications to classical logic, to modal logic and to lukasiewicz three - valued logic are considered.
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arxiv:1103.5111
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when a heisenberg honeycomb ferromagnet is irradiated by high frequency circularly polarized light, the underlying uncharged magnons acquire a time dependent aharonov casher phase, which makes it a floquet topological magnon insulator. in this context, we investigate the many body interaction effects of floquet magnons in laser irradiated heisenberg honeycomb ferromagnets with ocontaining dzyaloshinskii moriya interaction under the application of circularly polarized off resonant light. we demonstrate that the quantum ferromagnet systems periodically laser driven exhibits temperature driven topological phase transitions due to floquet magnon magnon interactions. the thermal hall effect of floquet magnons serves as a prominent signature for detecting these many body effects near the critical point, enabling experimental investigation into this phenomenon. our study complements the lack of previous theoretical works that the topological phase transition of the floquet magnon under the linear spin wave approximation is only tunable by the light field. our study presents a novel approach for constructing floquet topological phases in periodically driven quantum magnet systems that goes beyond the limitations of the linear spin wave theory. we provide numerical results based on the well known van der waals quantum magnet crx3 ( x = f, cl, br, and i ), calling for experimental implementation.
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arxiv:2312.06929
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lopes ( lofar prototype station ) is an array of dipole antennas used for detection of radio emission from air showers. it is co - located and triggered by the kascade ( karlsruhe shower core and array detector ) experiment, which also provides informations about air shower properties. even though neither lopes nor kascade are completely optimized for the detection of highly inclined events, a significant number of showers with zenith angle larger than 50 $ ^ o $ have been detected in the radio domain, and many with very high field strengths. investigation of inclined showers can give deeper insight into the nature of primary particles that initiate showers and also into the possibility that some of detected showers are triggered by neutrinos. in this paper, we show the example of such an event and present some of the characteristics of highly inclined showers detected by lopes.
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arxiv:astro-ph/0604273
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unpolarized cross sections and double - helicity asymmetries of single - inclusive positive and negative charged hadrons at midrapidity from p + p collisions at sqrt ( s ) = 62. 4 gev are presented. the phenix measurements for 1. 0 < p _ t < 4. 5 gev / c are consistent with perturbative qcd calculations at next - to - leading order in the strong coupling constant, alpha _ s. resummed pqcd calculations including terms with next - to - leading - log accuracy, yielding reduced theoretical uncertainties, also agree with the data. the double - helicity asymmetry, sensitive at leading order to the gluon polarization in a momentum - fraction range of 0. 05 ~ < x _ gluon ~ < 0. 2, is consistent with recent global parameterizations disfavoring large gluon polarization.
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arxiv:1202.4020
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decentralized monitoring ( dm ) refers to a monitoring technique, where each component must infer, based on a set of partial observations if the global property is satisfied. our work is inspired by the theoretical results presented by baurer and falcone at fm 2012, where the authors introduced an algorithm for distributing and monitoring ltl formulae, such that satisfaction or violation of specifications can be detected by local monitors alone. however, their work is based on the main assumption that neither the computation nor communication take time, hence it does not take into account how to set a sampling time among the components such that their local traces are consistent. in this work we provide a timed model in uppaal and we show a case study on a networked embedded systems board.
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arxiv:1308.5337
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we study the effect of nonlocality on the collapse properties of a self - focusing nonlinear schr \ " odinger system related to bose - einstein condensation problems. using a combination of moment techniques, time dependent variational methods and numerical simulations we present evidences in support of the hypothesis that nonlocal attractively interacting condensates cannot collapse when the dominant interaction term is due to finite range interactions. instead there apppear oscillations of the wave packet with a localized component whose size is of the order of the range of interactions. we discuss the implications of the results to collapse phenomena in negative scattering length bose - einstein condensates.
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arxiv:cond-mat/9912301
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we study a generalized two - species model on a ring. the original model [ 1 ] describes ordinary particles hopping exclusively in one direction in the presence of an impurity. the impurity hops with a rate different from that of ordinary particles and can be overtaken by them. here we let the ordinary particles hop also backward with the rate q. using matrix product ansatz ( mpa ), we obtain the relevant quadratic algebra. a finite dimensional representation of this algebra enables us to compute the stationary bulk density of the ordinary particles, as well as the speed of impurity on a set of special surfaces of the parameter space. we will obtain the phase structure of this model in the accessible region and show how the phase structure of the original model is modified. in the infinite - volume limit this model presents a shock in one of its phases.
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arxiv:cond-mat/9908327
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since the development of lasers, we have continuously sought to advance techniques and theory to obtain beams with a high degree of coherence, as natural light sources provide incoherent light. however, there are applications where it is advantageous to use partially coherent ( pc ) beams in a controlled manner, such as in propagation through turbulent media. to generate a pc beam in the laboratory or in simulations, specific theories and methods are required. in this article, we provide an introduction to pc beam theory, describing how to generate them through modal decompositions and a step - by - step guide for simulating and analyzing beam generation inspired by experiments. to illustrate the methods, we present gaussian schell - model beams as an example.
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arxiv:2403.09306
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understanding and recognizing emotions are important and challenging issues in the metaverse era. understanding, identifying, and predicting fear, which is one of the fundamental human emotions, in virtual reality ( vr ) environments plays an essential role in immersive game development, scene development, and next - generation virtual human - computer interaction applications. in this article, we used vr horror games as a medium to analyze fear emotions by collecting multi - modal data ( posture, audio, and physiological signals ) from 23 players. we used an lstm - based model to predict fear with accuracies of 65. 31 % and 90. 47 % under 6 - level classification ( no fear and five different levels of fear ) and 2 - level classification ( no fear and fear ), respectively. we constructed a multi - modal natural behavior dataset of immersive human fear responses ( vrmn - bd ) and compared it with existing relevant advanced datasets. the results show that our dataset has fewer limitations in terms of collection method, data scale and audience scope. we are unique and advanced in targeting multi - modal datasets of fear and behavior in vr stand - up interactive environments. moreover, we discussed the implications of this work for communities and applications. the dataset and pre - trained model are available at https : / / github. com / kindopstar / vrmn - bd.
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arxiv:2401.12133
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we propose to measure the coherent elastic neutrino nucleus scattering ( ce $ \ nu $ ns ) using a dual - phase liquid argon time projection chamber ( tpc ) with 200kg fiducial mass. the detector is expected to be adjacent to the juno - tao experiment and to be about 35m from a reactor core with 4. 6gw thermal power at taishan. the antineutrino flux is approximately 6 $ \ times10 ^ { 12 } $ cm $ ^ { - 1 } $ s $ ^ { - 1 } $ at this location, leading to more than 11, 000 coherent scattering events per day in the fiducial mass. however, the nuclear recoil energies concentrate in the sub - kev region, corresponding to less than ten ionisation electrons in the liquid argon. the detection of several ionisation electrons can be achieved in the dual - phase tpc due to the large amplification in the gas region. with a feasible detection threshold of four ionisation electrons, the signal rate is 955 per day. the detector is designed to be shielded well from cosmogenic backgrounds and ambient radioactivities to reach a 16 % background - to - signal ratio in the energy region of interest. with the large ce $ \ nu $ ns sample, the expected sensitivity of measuring the weak mixing angle $ \ sin ^ { 2 } \ theta _ { w } $, and of limiting the neutrino magnetic moment are discussed. in addition, a synergy between the reactor antineutrino ce $ \ nu $ ns experiment and the dark matter experiment is foreseen.
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arxiv:2012.00966
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the frequency - dependent conductivity $ \ sigma _ { xx } ( \ omega ) $ of 2d electrons subjected to a transverse magnetic field and smooth disorder is calculated. the interplay of landau quantization and disorder scattering gives rise to an oscillatory structure that survives in the high - temperature limit. the relation to recent experiments on photoconductivity by zudov { \ it et al. } and mani { \ it et al. } is discussed.
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arxiv:cond-mat/0304529
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we construct moduli spaces of representations of quivers over arbitrary schemes and show how moduli spaces of pointed curves of genus zero like the grothendieck - knudsen moduli spaces $ \ overline { m } _ { 0, n } $ and the losev - manin moduli spaces $ \ overline { l } _ n $ can be interpreted as inverse limits of moduli spaces of representations of certain bipartite quivers. we also investigate the case of more general hassett moduli spaces $ \ overline { m } _ { 0, a } $ of weighted pointed stable curves of genus zero.
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arxiv:1512.07785
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here we present the results of full experimental characterization of broadband cloaking of a finite - sized metallic cylinder at x - band. the cloaking effect is characterized by measuring the bistatic scattering patterns of uncloaked and cloaked objects in free space and then comparing these with each other. the results of the measurements demonstrate a broadband cloaking effect and are in good agreement with numerical predictions.
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arxiv:1109.6150
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we provide in this paper a concrete method for training a quantum neural network to maximize the relevant information about a property that is transmitted through the network. this is significant because it gives an operationally well founded quantity to optimize when training autoencoders for problems where the inputs and outputs are fully quantum. we provide a rigorous algorithm for computing the value of the quantum information bottleneck quantity within error $ \ epsilon $ that requires $ o ( \ log ^ 2 ( 1 / \ epsilon ) + 1 / \ delta ^ 2 ) $ queries to a purification of the input density operator if its spectrum is supported on $ \ { 0 \ } ~ \ bigcup ~ [ \ delta, 1 - \ delta ] $ for $ \ delta > 0 $ and the kernels of the relevant density matrices are disjoint. we further provide algorithms for estimating the derivatives of the qib function, showing that quantum neural networks can be trained efficiently using the qib quantity given that the number of gradient steps required is polynomial.
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arxiv:2212.02600
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optical phonons serve as the fast and efficient carriers of energy across periodic polymers due to their delocalization, large group velocity because of covalent bonding and large energy quantum compared to that for acoustic phonons, as it was observed in a number of recent measurements in different oligomers. however, this transport is dramatically sensitive to anharmonic interactions, including the unavoidable interaction with acoustic phonons responsible for the transport decoherence, suppressing ballistic transport at long distances. here we show that this decoherence is substantially suppressed if the group velocity of optical phonons is less than the sound velocity of acoustic phonons ; otherwise ballistic transport is substantially suppressed by a cherenkov ' s like emission of acoustic phonons. this conclusion is justified considering energy and momentum conservation during phonon absorption or emission and supported by the numerical evaluation of lifetimes of the optical phonons. it is also consistent with the recent experimental investigations of ballistic optical phonon transport in oligomers with minor exception of relatively short oligophenylenes.
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arxiv:2305.08972
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we present a unifying theory for the observed complex structures of the sp - bonded elements under pressure based on nearly free electron picture ( nfe ). in the intermediate pressure regime the dominant contribution to crystal structure arises from fermi - surface brillouin zone ( fsbz ) interactions - structures which allow this are favoured. this simple theory explains the observed crystal structures, transport properties, the evolution of internal and unit cell parameters with pressure. we illustrate it with experimental data for these elements and ab initio calculation for li.
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arxiv:cond-mat/0310380
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we introduce and analyze a class of galerkin - collocation discretization schemes in time for the wave equation. its conceptual basis is the establishment of a direct connection between the galerkin method for the time discretization and the classical collocation methods, with the perspective of achieving the accuracy of the former with reduced computational costs provided by the latter in terms of less complex linear algebraic systems. continuously differentiable in time discrete solutions are obtained by the application of a special quadrature rule involving derivatives. optimal order error estimates are proved for fully discrete approximations based on the galerkin - collocation approach. further, the concept of galerkin - collocation approximation is extended to twice continuously differentiable in time discrete solutions. a direct connection between the two families by a computationally cheap post - processing is presented. the error estimates are illustrated by numerical experiments.
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arxiv:1908.08238
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we exploit the unique characteristics of a sample of open clusters ( ocs ) and field stars for which high - precision 7li abundances and stellar parameters are homogeneously derived by the gaia - eso survey ( ges ). we derive possibly undepleted 7li abundances for 26 ocs and star forming regions with ages from young to old spanning a large range of galactocentric distances, which allows us to reconstruct the local late galactic evolution of lithium as well as its current abundance gradient along the disc. field stars are added to look further back in time and to constrain 7li evolution in other galactic components. the data are then compared to theoretical tracks from chemical evolution models that implement different 7li forges. we find that the upper envelope of the 7li abundances measured in field stars of nearly solar metallicities traces very well the level of lithium enrichment attained by the ism as inferred from observations of cluster stars. we confirm previous findings that the abundance of 7li in the solar neighbourhood does not decrease at supersolar metallicity. the comparison of the data with the chemical evolution model predictions favours a scenario in which the majority of the 7li abundance in meteorites comes from novae. current data also seem to suggest that the nova rate flattens out at later times. this requirement might have implications for the masses of the white dwarf nova progenitors and deserves further investigation. neutrino - induced reactions taking place in core - collapse supernovae also produce some fresh lithium. this likely makes a negligible contribution to the meteoritic abundance, but could be responsible for a mild increase of the 7li abundance in the ism of low - metallicity systems that would counterbalance the astration processes.
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arxiv:2106.11614
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this paper studies a scheduling problem in a parallel machine setting, where each machine must adhere to a predetermined fixed order for processing the jobs. given $ n $ jobs, each with processing times and deadlines, we aim to minimize the number of machines while ensuring deadlines are met and the fixed order is maintained. we show that the first - fit algorithm solves the problem optimally with unit processing times and is a 2 - approximation in the following four cases : ( 1 ) the order aligns with non - increasing slacks, ( 2 ) the order aligns with non - decreasing slacks, ( 3 ) the order aligns with non - increasing deadlines, and ( 4 ) the optimal solution uses at most 3 machines. for the general problem we provide an $ o ( \ log n ) $ - approximation.
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arxiv:2412.10760
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