text
stringlengths 1
3.65k
| source
stringlengths 15
79
|
|---|---|
in this paper we survey the notion and basic results on multivariate hasse - - schmidt derivations over arbitrary commutative algebras and we associate to such an object a family of classical derivations. we study the behavior of these derivations under the action of substitution maps and we prove that, in characteristic $ 0 $, the original multivariate hasse - - schmidt derivation can be recovered from the associated family of classical derivations. our constructions generalize a previous one by m. mirzavaziri in the case of a base field of characteristic $ 0 $.
|
arxiv:1810.08075
|
the recent technological advances in controlling and manipulating fluids have enabled the experimental realization of acoustic analogues of gravitational black holes. a flowing fluid provides an effective curved spacetime on which sound waves can propagate, allowing the simulation of gravitational geometries and related phenomena. the last decade has witnessed a variety of hydrodynamic experiments testing disparate aspects of black hole physics culminating in the recent experimental evidence of hawking radiation and penrose superradiance. in this perspective, we discuss the potential use of analogue hydrodynamic systems beyond classical general relativity towards the exploration of quantum gravitational effects. these include possible insights into the information - loss paradox, black hole physics with planck - scale quantum corrections, emergent gravity scenarios and the regularization of curvature singularities. we aim at bridging the gap between the non - overlapping communities of experimentalists working with classical and quantum fluids and quantum - gravity theorists, illustrating the opportunities made possible by the latest experimental and theoretical developments in these important areas of research
|
arxiv:2402.16136
|
we study the inverse problem of tuning interaction parameters between charged colloidal particles interacting with a hard - core repulsive yukawa potential, so that they assemble into specified crystal structures. here, we target the body - centered - cubic ( bcc ) structure which is only stable in a small region in the phase diagram of charged colloids and is, therefore, challenging to find. in order to achieve this goal, we use the statistical fluctuations in the bond orientational order parameters to tune the interaction parameters for the bcc structure, while initializing the system in the fluid phase, using the statistical physics - inspired inverse design ( sp - id ) algorithm [ 1 ]. we also find that this optimization algorithm correctly senses the fluid - solid phase boundaries for charged colloids. finally, we repeat the procedure employing the covariance matrix adaptation - evolution strategy ( cma - es ), a cutting edge optimization technique, and compare the relative efficacy of the two methods.
|
arxiv:1905.11061
|
in this paper, we mainly consider the speed selection problem for the classical lotka - volterra competition system. for the first time, we propose a sufficient and necessary condition for this long - standing problem from a new point of view. moreover, our results can also reveal the essence of the linearly selected problem for the monostable dynamical system from the observation of the decay rate of the minimal traveling wave solution.
|
arxiv:2207.03371
|
in a real hilbert space $ \ mathcal { h } $. given any function $ f $ convex differentiable whose solution set $ \ argmin _ { \ mathcal { h } } \, f $ is nonempty, by considering the proximal algorithm $ x _ { k + 1 } = \ text { prox } _ { \ b _ k f } ( d x _ k ) $, where $ 0 < d < 1 $ and $ ( \ b _ k ) $ is nondecreasing function, and by assuming some assumptions on $ ( \ b _ k ) $, we will show that the value of the objective function in the sequence generated by our algorithm converges in order $ \ mathcal { o } \ left ( \ frac { 1 } { \ beta _ k } \ right ) $ to the global minimum of the objective function, and that the generated sequence converges strongly to the minimum norm element of $ \ argmin _ { \ mathcal { h } } \, f $, we also obtain a convergence rate of gradient toward zero. afterward, we extend these results to non - smooth convex functions with extended real values.
|
arxiv:2309.13200
|
current absolute branching fractions of $ \ lambda _ c ^ + $ and $ d _ s ^ + $ mesons are limiting the determination of important measurements. they have only been measured at $ e ^ + e ^ - $ colliders. here techniques for measuring them at hadron colliders are discussed. the precision determination of $ \ lambda _ c ^ + \ to p k ^ - \ pi ^ + $ seems possible with current data, however the corresponding determination of $ d _ s ^ + \ to k ^ + k ^ - \ pi ^ + $ will require more integrated luminosity.
|
arxiv:1901.01593
|
we establish a general relation between the statistics of the local green ' s function for systems with chaotic wave scattering and a uniform energy loss ( absorption ) and its two - point correlation function for the same system without absorption. within the random matrix approach this kind of a fluctuation dissipation relation allows us to derive the explicit analytical expression for the joint distribution function of the real and imaginary parts of the local green function for all symmetry classes as well as at an arbitrary degree of the time - reversal symmetry breaking in the system. the outstanding problem of the orthogonal symmetry is further reduced to simple quadratures. the results can be applied, in particular, to the experimentally accessible impedance and reflection in a microwave cavity attached to a single - mode antenna.
|
arxiv:cond-mat/0502359
|
the atmospheres within our solar system can be categorized into four distinct climate regimes : " terrestrial ", " jovian ", " condensable ", and " exosphere ". beyond the three terrestrial planets ( excluding mercury ) and the four giant planets, collisional atmospheres are also found on smaller celestial bodies such as jupiter ' s moon io, saturn ' s moon titan, neptune ' s moon triton, and pluto. this article reviews the key characteristics of these atmospheres and the underlying physical and chemical processes that govern them. i focus on their thermal structures, chemical constituents, wind patterns, and the origins and losses of the atmospheres, and highlight the critical roles of surface ices and liquids, atmospheric hazes, and the space environments of their host planets in shaping these atmospheres. i dedicated this article to prof. zuo xiao ( 1936 - 2024 ) at peking university.
|
arxiv:2410.04595
|
high energy cosmic neutrino observations provide a sensitive test of lorentz invariance violation, which may be a consequence of quantum gravity theories. we consider a class of non - renormalizable, lorentz invariance violating operators that arise in an effective field theory description of lorentz invariance violation in the neutrino sector inspired by planck - scale physics and quantum gravity models. we assume a conservative generic scenario for the redshift distribution of extragalactic neutrino sources and employ monte carlo techniques to describe superluminal neutrino propagation, treating kinematically allowed energy losses of superluminal neutrinos caused by both vacuum pair emission and neutrino splitting. we consider efts with both non - renormalizable cpt - odd and non - renormalizable cpt - even operator dominance. we then compare the spectra derived using our monte carlo calculations in both cases with the spectrum observed by icecube in order to determine the implications of our results regarding planck - scale physics. we find that if the drop off in the neutrino flux above ~ 2 pev is caused by planck scale physics, rather than by a limiting energy in the source emission, a potentially significant pileup effect would be produced just below the drop off energy in the case of cpt - even operator dominance. however, such a clear drop off effect would not be observed if the cpt - odd, cpt - violating term dominates.
|
arxiv:1411.5889
|
this paper builds upon j. nilsson ' s classification of rank one $ \ mathcal { u } ( \ mathfrak { h } ) $ - free modules by extending the analysis to modules without rank restrictions, focusing on the category $ \ mathfrak { a } $ of $ \ mathcal { u } ( \ mathfrak { h } ) $ - finite $ \ mathfrak { g } $ - modules. a deeper investigation of the weighting functor $ \ mathcal { w } $ and its left derived functors, $ \ mathcal { w } _ * $, led to the proof that simple $ \ mathcal { u } ( \ mathfrak { h } ) $ - finite modules of infinite dimension are $ \ mathcal { u } ( \ mathfrak { h } ) $ - torsion free. furthermore, it is shown that these modules are $ \ mathcal { u } ( \ mathfrak { h } ) $ - free if they possess non - integral or singular central characters. it is concluded that the existence of $ \ mathcal { u } ( \ mathfrak { h } ) $ - torsion - free $ \ mathfrak { g } $ - modules is restricted to lie algebras of types a and c. the concept of an almost - coherent family, which generalizes o. mathieu ' s definition of coherent families, is introduced. it is proved that $ \ mathcal { w } ( m ) $, for a $ \ mathcal { u } ( \ mathfrak { h } ) $ - torsion - free module $ m $, falls within this class of weight modules. furthermore, a notion of almost - equivalence is defined to establish a connection between irreducible semi - simple almost - coherent families and o. mathieu ' s original classification. progress is also made in classifying simple modules within the category $ \ mathfrak { a } ^ { \ text { irr } } $, which consists of $ \ mathcal { u } ( \ mathfrak { h } ) $ - finite modules $ m $ with the property that $ \ mathcal { w } ( m ) $ is an irreducible almost - coherent family. a complete classification is achieved for type c, with partial classification for type a. finally, a conjecture is presented asserting that all simple $ \ mathfrak { sl } ( n + 1 ) $ - modules in $ \ mathfrak { a
|
arxiv:2411.18390
|
in type iib superstring compactifications, incorporating log - loop corrections and higher - derivative $ { ( \ alpha ^ \ prime ) } ^ 3 $ - corrections can stabilize the overall volume of the compact internal space at exponentially large values. this mechanism forms the basis of the perturbative large volume scenario ( lvs ). in this report, we briefly review two inflationary models realized within the perturbative lvs framework. the first one is the volume modulus inflation ( also known as inflection point inflation ) and the second one is popularly known as fibre inflation. using an explict calabi - yau orientifold, some concrete global embeddings of both models are also discussed.
|
arxiv:2505.01246
|
the construction of optimal template banks for matched - filtering searches is an example of the sphere covering problem. for parameter spaces with constant - coefficient metrics a ( near - ) optimal template bank is achieved by the a _ n * lattice, which is the best lattice - covering in dimensions n < = 5, and is close to the best covering known for dimensions n < = 16. generally this provides a substantially more efficient covering than the simpler hyper - cubic lattice. we present an algorithm for generating lattice template banks for constant - coefficient metrics and we illustrate its implementation by generating a _ n * template banks in n = 2, 3, 4 dimensions.
|
arxiv:0707.0428
|
in this paper, we dive into the reliability concerns of integrated gradients ( ig ), a prevalent feature attribution method for black - box deep learning models. we particularly address two predominant challenges associated with ig : the generation of noisy feature visualizations for vision models and the vulnerability to adversarial attributional attacks. our approach involves an adaptation of path - based feature attribution, aligning the path of attribution more closely to the intrinsic geometry of the data manifold. our experiments utilise deep generative models applied to several real - world image datasets. they demonstrate that ig along the geodesics conforms to the curved geometry of the riemannian data manifold, generating more perceptually intuitive explanations and, subsequently, substantially increasing robustness to targeted attributional attacks.
|
arxiv:2405.09800
|
tracking and identifying athletes on the pitch holds a central role in collecting essential insights from the game, such as estimating the total distance covered by players or understanding team tactics. this tracking and identification process is crucial for reconstructing the game state, defined by the athletes ' positions and identities on a 2d top - view of the pitch, ( i. e. a minimap ). however, reconstructing the game state from videos captured by a single camera is challenging. it requires understanding the position of the athletes and the viewpoint of the camera to localize and identify players within the field. in this work, we formalize the task of game state reconstruction and introduce soccernet - gsr, a novel game state reconstruction dataset focusing on football videos. soccernet - gsr is composed of 200 video sequences of 30 seconds, annotated with 9. 37 million line points for pitch localization and camera calibration, as well as over 2. 36 million athlete positions on the pitch with their respective role, team, and jersey number. furthermore, we introduce gs - hota, a novel metric to evaluate game state reconstruction methods. finally, we propose and release an end - to - end baseline for game state reconstruction, bootstrapping the research on this task. our experiments show that gsr is a challenging novel task, which opens the field for future research. our dataset and codebase are publicly available at https : / / github. com / soccernet / sn - gamestate.
|
arxiv:2404.11335
|
in this paper we describe a deep learning system that has been designed and built for the wassa 2017 emotion intensity shared task. we introduce a representation learning approach based on inner attention on top of an rnn. results show that our model offers good capabilities and is able to successfully identify emotion - bearing words to predict intensity without leveraging on lexicons, obtaining the 13th place among 22 shared task competitors.
|
arxiv:1708.05521
|
we construct smooth symplectic resolutions of the quotient of r ^ 2 under some infinite discrete sub - group of gl _ 2 ( r ) preserving a log - symplectic structure. this extends from algebraic geometry to smooth real differential geometry the du val symplectic resolution of c ^ 2 / g, with g \ subset sl _ 2 ( c ) a finite group. the first of these infinite groups is g = z, identified to triangular matrices with spectrum { 1 }. smooth functions on the quotient r ^ 2 / g come with a natural poisson bracket, and r ^ 2 / gis for an arbitrary k \ geq 1 set - isomorphic to the real du val singular variety a _ { 2k } = { ( x, y, z ) \ in r ^ 3, x ^ 2 + y ^ 2 = z ^ { 2k } }. we show that each one of the usual minimal resolutions of these du val varieties are symplectic resolutions of r ^ 2 / g. the same holds for g ' = z \ rtimes z / 2z ( identified to triangular matrices with spectrum { \ pm 1 } ), with the upper half of d _ { 2k + 1 } playing the role of a _ { 2k }.
|
arxiv:2104.01348
|
context. the prototypical low - mass young stellar object, t tauri, is a well - studied multiple system with at least three components. aims. we aim to explore the t tau system with the highest spatial resolution, study the time evolution of the known components, and re - determine the orbital parameters of the stars. methods. near - infrared classical imaging and integral field spectrograph observations were obtained during the science verification of sphere, the new high - contrast imaging facility at the vlt. the obtained fwhm of the primary star varies between 0. 050 " and 0. 059 ", making these the highest spatial resolution near - infrared images of the t tauri system obtained to date. results. our near - infrared images confirm the presence of extended emission south of t tau sa, reported in the literature. new narrow - band images show, for the first time, that this feature shows strong emission in both the br - { \ gamma } and h2 1 - 0 s ( 1 ) lines. broadband imaging at 2. 27 { \ mu } m shows that t tau sa is 0. 92 mag brighter than t tau sb, which is in contrast to observations from jan. 2014 ( when t tau sa was fainter than sb ), and demonstrates that t tau sa has entered a new period of high variability. the newly obtained astrometric positions of t tau sa and sb agree with orbital fits from previous works. the orbit of t tau s ( the center of gravity of sa and sb ) around t tau n is poorly constrained by the available observations and can be fit with a range of orbits ranging from a nearly circular orbit with a period of 475 years to highly eccentric orbits with periods up to 2. 7 * 10 ^ 4 years. we also detected a feature south of t tau n, at a distance of $ 144 \ pm 3 $ mas, which shows the properties of a new companion.
|
arxiv:1505.05722
|
we theoretically propose a scheme to synthesize photonic non - abelian electric field and spin - orbit coupling ( soc ) in the synthetic frequency dimension based on a polarization - multiplexed time - modulated ring resonator. inside the ring resonator, the cascade of polarization - dependent phase modulation, polarization rotation, and phase retardation enables a photonic realization of minimal soc composed of equal rashba and dresselhaus terms. the synthetic bands and associated spin textures can be effectively probed by the continuous - wave polarization - and time - resolved band structure measurements. meanwhile, the pulse dynamics in the frequency dimension can be manipulated by both synthetic abelian and non - abelian electric fields, leading to bloch oscillation, zitterbewegung, and their interplay dynamics. our proposed setup can be realized with free - space optics, fibers, and integrated photonics, and provides pseudospin control knobs for large - scale synthetic lattices based on frequency combs.
|
arxiv:2412.01841
|
skyrmions are localized, topologically non - trivial spin structures which have raised high hopes for future spintronic applications. a key issue is skyrmion stability with respect to annihilation into the ferromagnetic state. energy barriers for this collapse have been calculated taking only nearest neighbor exchange interactions into account. here, we demonstrate that exchange interactions beyond nearest neighbors can be essential to describe stability of skyrmionic spin structures. we focus on the prototypical film system pd / fe / ir ( 111 ) and demonstrate that an effective nearest - neighbor exchange or micromagnetic model can only account for equilibrium properties such as the skyrmion profile or the zero temperature phase diagram. however, energy barriers and critical fields of skyrmion collapse as well as skyrmion lifetimes are drastically underestimated since the energy of the transition state cannot be accurately described. antiskyrmions are not even metastable. our work shows that frustration of exchange interactions is a route towards enhanced skyrmion stability even in systems with a ferromagnetic ground state.
|
arxiv:1705.08122
|
flexible pcb quench antennas have been very useful in providing high - quality high - resolution data in low temperature superconducting magnet tests. similar multi - sensor arrays have been employed recently to cover a high temperature superconductor magnet tested at fnal. in the present work, data taking conditions and magnet features to support the analysis framework are discussed. then observations made during complete magnet powering cycles are described and analysis of quench antenna data are presented. based on results, improvements to instrumentation and data taking are debated. views on the future of flexible quench antenna sensors for hts magnet diagnostics and operational support are shared.
|
arxiv:2502.03176
|
we consider generating post - hoc explanations of clusters generated from various datasets using auxiliary information which was not used by clustering algorithms. following terminology used in previous work, we refer to the auxiliary information as tags. our focus is on two forms of explanations, namely disjunctive form ( where the explanation for a cluster consists of a set of tags ) and a two - clause conjunctive normal form ( cnf ) explanation ( where the explanation consists of two sets of tags, combined through the and operator ). we use integer linear programming ( ilp ) as well as heuristic methods to generate these explanations. we experiment with a variety of datasets and discuss the insights obtained from our explanations. we also present experimental results regarding the scalability of our explanation methods.
|
arxiv:2504.20846
|
we report on ' slow ' pulsing dynamics in a silica resonator - based laser system : by nesting a high - q rod - resonator inside an amplifying fiber cavity, we demonstrate that trains of microsecond pulses can be generated with repetition rates in the hundreds of kilohertz. we show that such pulses are produced with a period equivalent to several hundreds of laser cavity roundtrips via the interaction between the gain dynamics in the fiber cavity and the thermo - optical effects in the high - q resonator. experiments reveal that the pulsing properties can be controlled by adjusting the amplifying fiber cavity parameters. our results, confirmed by numerical simulations, provide useful insights on the dynamical onset of complex self - organization phenomena in resonator - based laser systems where thermo - optical effects play an active role. in addition, we show how the thermal state of the resonator can be probed and even modified by an external, counter - propagating optical field, thus hinting towards novel approaches for all - optical control and sensing applications.
|
arxiv:1903.09095
|
game theory on graphs is a basic tool in computer science. in this paper, we propose a new game - theoretic framework for studying the privacy protection of a user who interactively uses a software service. our framework is based on the idea that an objective of a user using software services should not be known to an adversary because the objective is often closely related to personal information of the user. we propose two new notions, o - indistinguishable strategy ( o - is ) and objective - indistinguishability equilibrium ( oie ). for a given game and a subset o of winning objectives ( or objectives in short ), a strategy of a player is o - indistinguishable if an adversary cannot shrink o by excluding any objective from o as an impossible objective. a strategy profile, which is a tuple of strategies of all players, is an oie if the profile is locally maximal in the sense that no player can expand her set of objectives indistinguishable from her real objective from the viewpoint of an adversary. we show that for a given multiplayer game with muller objectives, both of the existence of an o - is and that of oie are decidable.
|
arxiv:2307.00334
|
the problem of how staple yarns transmit tension is addressed within abstract models in which the amontons - coulomb friction laws yield a linear programming ( lp ) problem for the tensions in the fiber elements. we find there is a percolation transition such that above the percolation threshold the transmitted tension is in principle unbounded, we determine that the mean slack in the lp constraints is a suitable order parameter to characterize this supercritical state. we argue the mechanism is generic, and in practical terms corresponds to a switch from a ductile to a brittle failure mode accompanied by a significant increase in mechanical strength.
|
arxiv:1804.07606
|
we develop a method for transmission stabilization and robust dynamic switching for colliding optical soliton sequences in broadband waveguide systems with nonlinear gain and loss. the method is based on employing hybrid waveguides, consisting of spans with linear gain and cubic loss, and spans with linear loss, cubic gain, and quintic loss. we show that amplitude dynamics is described by a hybrid lotka - volterra ( lv ) model, and use the model to determine the physical parameter values required for enhanced transmission stabilization and switching. numerical simulations with the coupled nonlinear schr \ " odinger equations confirm the predictions of the lv model, and show stable transmission over distances larger by an order of magnitude compared with uniform waveguides with linear gain and cubic loss. moreover, multiple on - off and off - on dynamic switching events are demonstrated over a wide range of soliton amplitudes, showing the superiority of hybrid waveguides compared with static switching in uniform waveguides, considered in earlier studies.
|
arxiv:1405.7071
|
simulations of field theories on noisy quantum computers must contend with errors introduced by that noise. for gauge theories, a large class of errors violate gauge symmetry, and thus may result in unphysical processes occurring in the simulation. we present a method, applicable to non - abelian gauge theories, for suppressing coherent gauge drift errors through the repeated application of pseudorandom gauge transformation. in cases where the dominant errors are gauge - violating, we expect this method to be a practical way to improve the accuracy of nisq - era simulations.
|
arxiv:2005.12688
|
in this brief, we consider the constrained optimization problem underpinning model predictive control ( mpc ). we show that this problem can be decomposed into an unconstrained optimization problem with the same cost function as the original problem and a constrained optimization problem with a modified cost function and dynamics that have been precompensated according to the solution of the unconstrained problem. in the case of linear systems subject to a quadratic cost, the unconstrained problem has the familiar lqr solution and the constrained problem reduces to a minimum - norm projection. this implies that solving linear mpc problems is equivalent to precompensating a system using lqr and applying mpc to penalize only the control input. we propose to call this a constraint - separation principle and discuss the utility of both constraint separation and general decomposition in the design of mpc schemes and the development of numerical solvers for mpc problems.
|
arxiv:2005.01296
|
chandran et al. ( siam j. comput. ' 14 ) formally introduced the cryptographic task of position verification, where they also showed that it cannot be achieved by classical protocols. in this work, we initiate the study of position verification protocols with classical verifiers. we identify that proofs of quantumness ( and thus computational assumptions ) are necessary for such position verification protocols. for the other direction, we adapt the proof of quantumness protocol by brakerski et al. ( focs ' 18 ) to instantiate such a position verification protocol. as a result, we achieve classically verifiable position verification assuming the quantum hardness of learning with errors. along the way, we develop the notion of 1 - of - 2 non - local soundness for a natural non - local game for 1 - of - 2 puzzles, first introduced by radian and sattath ( aft ' 19 ), which can be viewed as a computational unclonability property. we show that 1 - of - 2 non - local soundness follows from the standard 2 - of - 2 soundness ( and therefore the adaptive hardcore bit property ), which could be of independent interest.
|
arxiv:2109.07517
|
we present an absolute $ ^ 3 $ he polarimetry method based on thermal neutron transmission for a double - chambered cell. this method utilizes the fact that a $ ^ 3 $ he nucleus has a large absorption cross section and a spin dependence for thermal neutrons. the cell had a pumping chamber and a target chamber. polarized $ ^ 3 $ he gas was produced in the pumping chamber by seop and then diffused into the target chamber. the $ ^ 3 $ he polarization in the target chamber was determined by comparing the neutron transmissions with the polarized and unpolarized targets. the measurement was performed at the riken accelerator - driven compact neutron source. the $ ^ 3 $ he polarization in the target chamber was determined with a statistical error of 1. 8 % and systematic uncertainty of 0. 6 %. this method can be used to obtain high - precision data of spin observables in few - nucleon scattering for the investigation of nuclear forces.
|
arxiv:2209.12484
|
we have fabricated a high - quality monolayer wse2 film on bilayer graphene by epitaxial growth, and revealed the electronic states by spin - and angle - resolved photoemission spectroscopy. we observed a direct energy gap at the brillounin - zone corner in contrast to the indirect nature of gap in bulk wse2, which is attributed to the lack of interlayer interaction and the breaking of space - inversion symmetry in monolayer film. a giant spin splitting of ~ 0. 5 ev, which is the largest among known monolayer transition - metal dichalcogenides, is observed in the energy band around the zone corner. the present results suggest a high potential applicability of wse2 to develop advanced devices based with the coupling of spin - and valley - degrees of freedom.
|
arxiv:1508.01249
|
the identification of an unknown quantum gate is a significant issue in quantum technology. in this paper, we propose a quantum gate identification method within the framework of quantum process tomography. in this method, a series of pure states are inputted to the gate and then a fast state tomography on the output states is performed and the data are used to reconstruct the quantum gate. our algorithm has computational complexity $ o ( d ^ 3 ) $ with the system dimension $ d $. the algorithm is compared with maximum likelihood estimation method for the running time, which shows the efficiency advantage of our method. an error upper bound is established for the identification algorithm and the robustness of the algorithm against the purity of input states is also tested. we perform quantum optical experiment on single - qubit hadamard gate to verify the effectiveness of the identification algorithm.
|
arxiv:1707.06039
|
a direct search for the standard model higgs boson, h, produced in association with a vector boson, v ( w or z ), and decaying to a charm quark pair is presented. the search uses a data set of proton - proton collisions corresponding to an integrated luminosity of 35. 9 fb $ ^ { - 1 } $, collected by the cms experiment at the lhc in 2016, at a centre - of - mass energy of 13 tev. the search is carried out in mutually exclusive channels targeting specific decays of the vector bosons : w $ \ to $ $ \ ell \ nu $, z $ \ to $ $ \ ell \ ell $, and z $ \ to $ $ \ nu \ nu $, where $ \ ell $ is an electron or a muon. to fully exploit the topology of the h boson decay, two strategies are followed. in the first one, targeting lower vector boson transverse momentum, the h boson candidate is reconstructed via two resolved jets arising from the two charm quarks from the h boson decay. a second strategy identifies the case where the two charm quark jets from the h boson decay merge to form a single jet, which generally only occurs when the vector boson has higher transverse momentum. both strategies make use of novel methods for charm jet identification, while jet substructure techniques are also exploited to suppress the background in the merged - jet topology. the two analyses are combined to yield a 95 % confidence level observed ( expected ) upper limit on the cross section $ \ sigma $ ( h ) $ \ mathcal { b } $ ( h $ \ to $ $ \ mathrm { c \ bar { c } } $ ) of 4. 5 ( 2. 4 $ ^ { + 1. 0 } _ { - 0. 7 } $ ) pb, corresponding to 70 ( 37 ) times the standard model prediction.
|
arxiv:1912.01662
|
bm orionis, eclipsing binary system that located in the center of orion nebula cluster posses several enigmatic problems. its intrinsic nature and nebular environment make it harder to measure the physical parameters of the system, but it is believed as algol type binary where secondary component is pre - main sequence star with larger radius. to assure this, several stellar models ( $ m _ 1 = 5. 9 $ { m _ { \ odot } } and $ m _ 2 = 2. 0 $ { m _ { \ odot } } ) are created and simulated using mesa. models with rigid rotation of $ \ omega = 10 ^ { - 5 } $ rad / s exhibit considerable similar properties during pre - main sequence stage, but 2. 0 { \ msun } at assumed age of $ \ sim10 ^ 6 $ is $ 6. 46 $ times dimmer than observed secondary star. there must be an external mechanism to fill this luminosity gap. then, simulated post - main sequence binary evolution of bm ori that involves mass transfer shows that primary star will reach helium sequence with the mass of $ \ sim0. 8 $ { \ msun } before second stage mass transfer.
|
arxiv:1312.2737
|
we present a formalism for calculating the probability distribution of the most massive primordial black holes ( pbhs ) expected within an observational volume. we show how current observational upper bounds on the fraction of pbhs in dark matter translate to constraints on extreme masses of primordial black holes. we demonstrate the power of our formalism via a case study, and argue that our formalism can be used to produce extreme - value distributions for a wide range of pbh formation theories.
|
arxiv:1910.12311
|
we investigate the possible effects of the supernova ejecta hitting the companion star in iptf 13bvn, focusing on the observable features when it becomes visible. iptf 13bvn is a type ib supernova that may become the first case that its progenitor is identified as a binary by near future observations. according to calculations by bersten et al. ( 2014 ), the progenitor should have a mass $ \ approx3. 5m _ \ odot $ to reproduce the supernova light curve, and such compact stars could only be produced via binary evolution. this is one of the reasons that we expect the progenitor to be a binary, but it should be confirmed by observing the remaining companion after the supernova. their evolutionary calculations suggest that the companion star will be an overluminous ob star at the moment of supernova. with a combination of hydrodynamical and evolutionary simulations, we find that the secondary star will be heated by the supernova ejecta and expand to have larger luminosities and lower surface effective temperatures. the star will look rather like a red super giant, and this should be taken into account when searching for the companion star in the supernova ejecta in future observations.
|
arxiv:1504.01845
|
we investigate the geometric picture of the level surfaces of quantum entanglement and geometric measure of quantum discord ( gmqd ) of a class of x - states, respectively. this pictorial approach provides us a direct understanding of the structure of entanglement and gmqd. the dynamic evolution of gmqd under two typical kinds of quantum decoherence channels is also investigated. it is shown that there exists a class of initial states for which the gmqd is not destroyed by decoherence in a finite time interval. furthermore, we establish a factorization law between the initial and final gmqd, which allows us to infer the evolution of entanglement under the influences of the environment.
|
arxiv:1112.4318
|
variational inference with a factorized gaussian posterior estimate is a widely used approach for learning parameters and hidden variables. empirically, a regularizing effect can be observed that is poorly understood. in this work, we show how mean field inference improves generalization by limiting mutual information between learned parameters and the data through noise. we quantify a maximum capacity when the posterior variance is either fixed or learned and connect it to generalization error, even when the kl - divergence in the objective is rescaled. our experiments demonstrate that bounding information between parameters and data effectively regularizes neural networks on both supervised and unsupervised tasks.
|
arxiv:1902.04340
|
this report presents a framework called segment and track anything ( samtrack ) that allows users to precisely and effectively segment and track any object in a video. additionally, sam - track employs multimodal interaction methods that enable users to select multiple objects in videos for tracking, corresponding to their specific requirements. these interaction methods comprise click, stroke, and text, each possessing unique benefits and capable of being employed in combination. as a result, sam - track can be used across an array of fields, ranging from drone technology, autonomous driving, medical imaging, augmented reality, to biological analysis. sam - track amalgamates segment anything model ( sam ), an interactive key - frame segmentation model, with our proposed aot - based tracking model ( deaot ), which secured 1st place in four tracks of the vot 2022 challenge, to facilitate object tracking in video. in addition, sam - track incorporates grounding - dino, which enables the framework to support text - based interaction. we have demonstrated the remarkable capabilities of sam - track on davis - 2016 val ( 92. 0 % ), davis - 2017 test ( 79. 2 % ) and its practicability in diverse applications. the project page is available at : https : / / github. com / z - x - yang / segment - and - track - anything.
|
arxiv:2305.06558
|
in the chirally - invariant context of the $ u _ { em } ( 1 ) $ gauge interaction and four - fermion interactions for ordinary and mirror fermions, the schwinger - dyson equation for the fermion self - energy function is studied on a lattice. we find that a sensible infrared limit can be defined on a critical surface, which is consistent with the critical line found in the continuum theory.
|
arxiv:hep-lat/9402015
|
3d point cloud semantic and instance segmentation is crucial and fundamental for 3d scene understanding. due to the complex structure, point sets are distributed off balance and diversely, which appears as both category imbalance and pattern imbalance. as a result, deep networks can easily forget the non - dominant cases during the learning process, resulting in unsatisfactory performance. although re - weighting can reduce the influence of the well - classified examples, they cannot handle the non - dominant patterns during the dynamic training. in this paper, we propose a memory - augmented network to learn and memorize the representative prototypes that cover diverse samples universally. specifically, a memory module is introduced to alleviate the forgetting issue by recording the patterns seen in mini - batch training. the learned memory items consistently reflect the interpretable and meaningful information for both dominant and non - dominant categories and cases. the distorted observations and rare cases can thus be augmented by retrieving the stored prototypes, leading to better performances and generalization. exhaustive experiments on the benchmarks, i. e. s3dis and scannetv2, reflect the superiority of our method on both effectiveness and efficiency. not only the overall accuracy but also nondominant classes have improved substantially.
|
arxiv:2001.01349
|
massive multiple input multiple output ( m - mimo ) technology plays a pivotal role in fifth - generation ( 5g ) and beyond communication systems, offering a wide range of benefits, from increased spectral efficiency ( se ) to enhanced energy efficiency and higher reliability. however, these advantages are contingent upon precise channel state information ( csi ) availability at the base station ( bs ). ensuring precise csi is challenging due to the constrained size of the coherence interval and the resulting limitations on pilot sequence length. therefore, reusing pilot sequences in adjacent cells introduces pilot contamination, hindering se enhancement. this paper reviews recent advancements and addresses research challenges in mitigating pilot contamination and improving channel estimation, categorizing the existing research into three broader categories : pilot assignment schemes, advanced signal processing methods, and advanced channel estimation techniques. salient representative pilot mitigation / assignment techniques are analyzed and compared in each category. lastly, possible future research directions are discussed.
|
arxiv:2404.19238
|
light propagation through an ensemble of ultra - cold rydberg atoms in electromagnetically induced transparency ( eit ) configuration is studied. in strongly interacting rydberg eit media, non - linear optical effects lead to a non - trivial dependence of the degree of probe beam attenuation on the medium density and on its initial intensity. we develop a monte carlo rate equation model that self - consistently includes the effect of the probe beam attenuation to investigate the steady state of the rydberg medium driven by two laser fields. we compare our results to recent experimental data and to results of other state - of - the - art models for light propagation in rydberg eit - media. we find that for low probe field intensities, our results match the experimental data best if a density - dependent dephasing rate is included in the model. at higher probe intensities, our model deviates from other theoretical approaches, as it predicts a spectral asymmetry together with line broadening. these are likely due to off - resonant excitation channels, which however have not been observed in recent experiments. atomic motion and coupling to additional rydberg levels are discussed as possible origins for these deviations.
|
arxiv:1305.1458
|
we express one - loop string amplitudes involving both open and closed strings as sum over pure open string amplitudes. these findings generalize the analogous tree - level result to higher loops and extend the tree - level observation that in gravitational amplitudes a graviton can be traded for two gluons. our results are derived from analytic continuation of closed string world - sheet coordinates on the cylinder resulting in pairs of real open string coordinates located at the two cylinder boundaries subject to a one - loop kernel. the latter depends on the loop momentum flowing between the two cylinder boundaries and relates to intersection theory for twisted cycles. finally, contact is made with one - loop open string monodromy relations. the latter contain a boundary term, which is related to non - physical contours on the cylinder. a physical interpretation of the latter in terms of a closed string insertion is given.
|
arxiv:2105.06888
|
we discuss the relation between the highest energy cosmic rays ( uhecr ) and uhe neutrinos. the neutrinos produced in the sources of optically thin astrophysical sources have been linked to the uhecr emissivity of the universe. the fluxes of cosmogenic neutrinos, generated in propagation by uhecr, also reflect the acceleration of these particles, the maximum acceleration energy, and the cosmological evolution of their sources.
|
arxiv:0711.1872
|
classification systems are normally trained by minimizing the cross - entropy between system outputs and reference labels, which makes the kullback - leibler divergence a natural choice for measuring how closely the system can follow the data. precision and recall provide another perspective for measuring the performance of a classification system. non - binary references can arise from various sources, and it is often beneficial to use the soft labels for training instead of the binarized data. however, the existing definitions for precision and recall require binary reference labels, and binarizing the data can cause erroneous interpretations. we present a novel method to calculate precision, recall and f - score without quantizing the data. the proposed metrics extend the well established metrics as the definitions coincide when used with binary labels. to understand the behavior of the metrics we show simple example cases and an evaluation of different sound event detection models trained on real data with soft labels.
|
arxiv:2309.13938
|
a key goal in developing molecular microrobots that mimic real - world animal dynamic behavior is to understand better the self - continuous progressive motion resulting from collective molecular transformation. this study reports, for the first time, the experimental realization of directional swimming of a microcrystal that exhibits self - continuous reciprocating motion in a two - dimensional water tank. although the reciprocal flip motion of the crystals was like that of a fish wagging its tail fin, many of the crystals swam in the opposite direction to which a fish would swim. here we explore the directionality generation mechanism and physical features of the swimming behavior by constructing a mathematical model for the crystalline flapper. the results show that a tiny crystal with a less - deformable part in its flip fin exhibits a pull - type stroke swimming, while a crystal with a fin that uniformly deforms exhibits push - type kicking motion.
|
arxiv:2108.13667
|
hateful rhetoric is plaguing online discourse, fostering extreme societal movements and possibly giving rise to real - world violence. a potential solution to this growing global problem is citizen - generated counter speech where citizens actively engage in hate - filled conversations to attempt to restore civil non - polarized discourse. however, its actual effectiveness in curbing the spread of hatred is unknown and hard to quantify. one major obstacle to researching this question is a lack of large labeled data sets for training automated classifiers to identify counter speech. here we made use of a unique situation in germany where self - labeling groups engaged in organized online hate and counter speech. we used an ensemble learning algorithm which pairs a variety of paragraph embeddings with regularized logistic regression functions to classify both hate and counter speech in a corpus of millions of relevant tweets from these two groups. our pipeline achieved macro f1 scores on out of sample balanced test sets ranging from 0. 76 to 0. 97 - - - accuracy in line and even exceeding the state of the art. on thousands of tweets, we used crowdsourcing to verify that the judgments made by the classifier are in close alignment with human judgment. we then used the classifier to discover hate and counter speech in more than 135, 000 fully - resolved twitter conversations occurring from 2013 to 2018 and study their frequency and interaction. altogether, our results highlight the potential of automated methods to evaluate the impact of coordinated counter speech in stabilizing conversations on social media.
|
arxiv:2006.01974
|
the recent trend in 2d multiple object tracking ( mot ) is jointly solving detection and tracking, where object detection and appearance feature ( or motion ) are learned simultaneously. despite competitive performance, in crowded scenes, joint detection and tracking usually fail to find accurate object associations due to missed or false detections. in this paper, we jointly model counting, detection and re - identification in an end - to - end framework, named countingmot, tailored for crowded scenes. by imposing mutual object - count constraints between detection and counting, the countingmot tries to find a balance between object detection and crowd density map estimation, which can help it to recover missed detections or reject false detections. our approach is an attempt to bridge the gap of object detection, counting, and re - identification. this is in contrast to prior mot methods that either ignore the crowd density and thus are prone to failure in crowded scenes, or depend on local correlations to build a graphical relationship for matching targets. the proposed mot tracker can perform online and real - time tracking, and achieves the state - of - the - art results on public benchmarks mot16 ( mota of 79. 7 ), mot17 ( mota of 81. 3 % ) and mot20 ( mota of 78. 9 % ).
|
arxiv:2212.05861
|
fixed point iterations are known to generate chaos, for some values in their parameter range. it is an established fact that turing machines are fixed point iterations. however, as these machines operate in integer space, the standard notions of a chaotic system is not readily applicable for them. changing the state space of turing machines from integer to rational space, the condition for chaotic dynamics can be suitably established, as presented in the current paper. further it is deduced that, given random input, computation performed by a universal turing machine would be ' almost surely ' chaotic.
|
arxiv:1111.4949
|
given a biquandle $ ( x, s ) $, a function $ \ tau $ with certain compatibility and a pair of { \ em non commutative cocyles } $ f, h : x \ times x \ to g $ with values in a non necessarily commutative group $ g $, we give an invariant for singular knots / links. given $ ( x, s, \ tau ) $, we also define a universal group $ u _ { nc } ^ { fh } ( x ) $ and universal functions governing all 2 - cocycles in $ x $, and exhibit examples of computations. when the target group is abelian, a notion of { \ em abelian cocycle pair } is given and the " state sum " is defined for singular knots / links. computations generalizing linking number for singular knots are given. as for virtual knots, a " self - linking number " may be defined for singular knots
|
arxiv:1910.04042
|
the importance of incorporating flavor constraints, when providing bounds on new physics is stressed. as is well known it is very difficult for models of new physics to have scales lighter than about 10 tev once flavor constraints are built in. although, in the conventional sense, this higher scale means more tuning, it may well make the underlying theory simpler as illustrated with one example. direct production of new particles heavier than about 5 tev becomes very difficult at lhc though indirect signals such as deviations in the higgs to gamma gamma branching ratio may still be possible. also of course precision studies at low energy facilities can be useful for detecting new phenomena. for direct production of new particles over 5 - 10 tev a new high energy collider perhaps at 100 tev is highly desirable. indeed, a very strong physics case can be made for such a machine. it can be used to significantly improve many bounds as well as allow a multitude of direct searches in many channels without relying on specific models. naturalness can be tested by another factor of about 50 past lhc to o ( $ 10 ^ { - 4 } $ ), a valuable achievement in itself.
|
arxiv:1511.09090
|
matrix factorization methods are extensively employed to understand complex data. in this paper, we introduce the cross - product penalized component analysis ( xcan ), a sparse matrix factorization based on the optimization of a loss function that allows a trade - off between variance maximization and structural preservation. the approach is based on previous developments, notably ( i ) the sparse principal component analysis ( spca ) framework based on the lasso, ( ii ) extensions of spca to constrain both modes of the factorization, like co - clustering or the penalized matrix decomposition ( pmd ), and ( iii ) the group - wise principal component analysis ( gpca ) method. the result is a flexible modeling approach that can be used for data exploration in a large variety of problems. we demonstrate its use with applications from different disciplines.
|
arxiv:1907.00032
|
plasmonic nanostructures provide local field enhancement to be used as efficiency - boosting tools in fluorescence - based applications. for photostable quantum dots ( qds ) to have enhanced emission, their size and exact location in the proximity of plasmonic nanostructure become key parameters while constructing light emitting devices. however, plasmonic nanostructures mostly suffer from non - radiative energy transfer at close proximity, which hinders the ultimate performance of fluorophores. in this work, we provided critical interparticle distances through finite difference time domain ( fdtd ) simulations, where the radiative decay rate is equalized to the non - radiative counterpart for light emitting qd - based technologies. to show the promises of the qd placement at a critical distance, we demonstrate an optical switch for the fluorescence efficiency of a cdse / zns core - shell qd ( csqd ) by optically exciting the silver nanoparticle ( agnp ) placed at a critical distance. while the provided single particle spectroscopy allows for the observation of heterogeneity in csqd - agnp coupling that is often masked in ensemble measurements, our benchmark study serves as a base reference for the development of qd - based light emitting technologies by resolving the optically switchable active tuning of radiative decay rates.
|
arxiv:2504.11541
|
generative conversational interfaces powered by large language models ( llms ) typically stream output token - by - token at a rate determined by computational budget, often neglecting actual human reading speeds and the cognitive load associated with the content. this mismatch frequently leads to inefficient use of computational resources. for example, in cloud - based services, streaming content faster than users can read appears unnecessary, resulting in wasted computational resources and potential delays for other users, particularly during peak usage periods. to address this issue, we propose an adaptive streaming method that dynamically adjusts the pacing of llm streaming output in real - time based on inferred cognitive load. our approach estimates the cognitive load associated with streaming content and strategically slows down the stream during complex or information - rich segments, thereby freeing computational resources for other users. our statistical analysis of computational savings, combined with crowdsourced user studies, provides insights into the trade - offs between service efficiency and user satisfaction, demonstrating that our method can significantly reduce computational consumption up to 16. 8 \ %. this context - aware computational resource management strategy presents a practical framework for enhancing system efficiency in cloud - based conversational ai interfaces without compromising user experience.
|
arxiv:2504.17999
|
we analyze the quantum dynamics of a scalar field in a spacetime incorporating dual topological defects, specifically a cosmic string and a global monopole. utilizing a generalized metric that encapsulates the combined geometric effects of both defects, we solve the klein - - gordon equation through separation of variables and examine the role of external potentials, with a focus on the generalized cornell potential. a comparative analysis against the pure coulomb potential is conducted to elucidate the modifications induced by the additional linear term. the presence of topological defects deforms the radial components of the wave equation, leading to energy spectrum shifts in bound states and alterations in scattering phase shifts. the results obtained provide a deeper theoretical foundation for understanding the behavior of spin - 0 particles in nontrivial spacetime geometries, particularly in the presence of distinct potential interactions.
|
arxiv:2504.07191
|
solving np - hard constrained combinatorial optimization problems using quantum algorithms remains a challenging yet promising avenue toward quantum advantage. variational quantum algorithms ( vqas ), such as the variational quantum eigensolver ( vqe ), typically require constrained problems to be reformulated as unconstrained ones using penalty methods. a common approach introduces slack variables and quadratic penalties in the qubo formulation to handle inequality constraints. however, this leads to increased qubit requirements and often distorts the optimization landscape, making it harder to find high - quality feasible solutions. to address these issues, we explore a slack - free formulation that directly encodes inequality constraints using custom penalty functions, specifically the exponential function and the heaviside step function. these step - like penalties suppress infeasible solutions without introducing additional qubits or requiring finely tuned weights. inspired by recent developments in quantum annealing and threshold - based constraint handling in gate - based algorithms, we implement and evaluate our approach on the multiple knapsack problem ( mkp ). experimental results show that the step - based formulation significantly improves feasibility and optimality rates compared to unbalanced penalization, while reducing overall qubit overhead.
|
arxiv:2504.12611
|
the dynamic magnetic behaviors of the spin - 1 blume - capel ising bilayer system ( bcis ) are studied in an oscillating external magnetic field on a two - layer square lattice by utilizing the mean field theory based on glauber - type stochastic dynamics ( dmft ). the dynamic equations describing the time - dependencies of the average magnetizations are obtained with the master equation. the dynamic phases in this system are found by solving these dynamic equations. the temperature dependence of the dynamic order parameters is examined to characterize the nature ( continuous or discontinuous ) of the phase transitions and to obtain the dynamic phase transition points ( dpt ). the dynamic phase diagrams are shown for ferromagnetic / ferromagnetic, antiferromagnetic / antiferromagnetic, antiferromagnetic / antiferromagnetic interactions in the plane of the reduced temperature versus magnetic field amplitude and they display dynamic tricritical and reentrant behavior as well as the dynamic triple point.
|
arxiv:1411.7146
|
we investigate f ( t ) cosmology in both the background, as well as in the perturbation level, and we present the general formalism for reconstructing the equivalent one - parameter family of f ( t ) models for any given dynamical dark energy scenario. despite the completely indistinguishable background behavior, the perturbations break this degeneracy and the growth histories of all these models differ from one another. as an application we reconstruct the f ( t ) equivalent for quintessence, and we show that the deviation of the matter overdensity evolution is strong for small scales and weak for large scales, while it is negligible for large redshifts.
|
arxiv:1010.2215
|
we derive a new constraint on the expansion history of the universe by applying the cosmic chronometers method, studying the age evolution of high - redshift galaxies with a full - spectral - fitting approach. we select a sample of 39 massive ( $ log ( m / m _ \ odot ) > 10. 8 $ ) and passive ( $ log ( ssfr / yr ^ { - 1 } ) < - 11 $ ) galaxies from the data release 4 of the vandels survey at $ 1 < z < 1. 5 $, combining different selection criteria to minimize the potential contamination by star - forming outliers. we perform full - spectral - fitting jointly on spectra and photometry of our sources with the code bagpipes, without any cosmological assumption on the age of the population. the derived physical properties of the selected galaxies are characteristic of a passive population, with short star formation timescales ( $ < \ tau > = 0. 28 \ pm0. 02 $ gyr ), low dust extinction ( $ < a _ { v, dust } > = 0. 43 \ pm0. 02 $ mag ), and sub - solar metallicities ( $ < z / z _ { \ odot } > = 0. 44 \ pm0. 01 $ ). the ages show a decreasing trend with redshift compatible with a standard cosmological model, even if no cosmological constraint is assumed in the fit, and a clear mass - downsizing pattern. testing the impact of the star formation history on the results, we find only a maximum 2 \ % fluctuation in age and metallicity. by fitting the median age - redshift relation with a flat $ \ lambda $ cdm model and assuming a gaussian prior on $ \ omega _ { m, 0 } = 0. 3 \ pm0. 02 $ from late - universe probes, we obtain $ h _ 0 = 67 _ { - 15 } ^ { + 14 } \ : km \ : s ^ { - 1 } \ : mpc ^ { - 1 } $. in the end, we derive a new estimate of the hubble parameter with the cosmic chronometers method, $ h ( z = 1. 26 ) = 135 \ pm65 \ : km \ : s ^ { - 1 } \ : mpc ^ { - 1 } $ including statistical and systematic errors. while the error budget is currently dominated by the scarcity of the sample, this work proves the
|
arxiv:2305.16387
|
we present time - series linear - polarization observations of the bright o4 supergiant $ \ zeta $ puppis. the star is found to show polarization variation on timescales of around an hour and longer. many of the observations were obtained contemporaneously with transiting exoplanet survey satellite ( tess ) photometry. we find that the polarization varies on similar timescales to those seen in the tess light - curve. the previously reported 1. 78 - day photometric periodicity is seen in both the tess and polarization data. the amplitude ratio of photometry to polarization is ~ 9 for the periodic component and the polarization variation is oriented along position angle ~ 70 deg - 160 deg. higher - frequency stochastic variability is also seen in both datasets with an amplitude ratio of ~ 19 and no preferred direction. we model the polarization expected for a rotating star with bright photospheric spots and find that models that fit the photometric variation produce too little polarization variation to explain the observations. we suggest that the variable polarization is more likely the result of scattering from the wind, with corotating interaction regions producing the periodic variation and a clumpy outflow producing the stochastic component. the h $ \ alpha $ emission line strength was seen to increase by 10 % in 2021 with subsequent observations showing a return to the pre - 2018 level.
|
arxiv:2402.13383
|
i construct a quantum field theory model with discrete scale invariance at tree level. the model has some unusual mathematical properties ( such as the appearance of $ q $ - hypergeometric series ) and may possibly have some interesting physical properties as well. in this note, i explore some possible physics that could be regarded as a violation of standard effective field theory ideas.
|
arxiv:1606.03405
|
let $ m _ { \ beta } $ denote the moduli space of stable one - dimensional sheaves on a del pezzo surface $ s $, supported on curves of class $ \ beta $ with euler characteristic one. we show that the divisibility property of the poincar \ ' e polynomial of $ m _ { \ beta } $, proposed by choi - van garrel - katz - takahashi follows from bousseau ' s conjectural refined sheaves / gromov - witten correspondence. since this correspondence is known for $ s = \ mathbb { p } ^ 2 $, our result proves choi - van garrel - katz - takahashi ' s conjecture in this case. for $ s = \ mathbb { p } ^ 2 $, our proof also introduces a novel approach to computing the poincar \ ' e polynomials using gromov - witten invariants of local $ \ mathbb { p } ^ 2 $ and a local elliptic curve. specifically, we compute the poincar \ ' e polynomials of $ m _ { d } $ with degrees $ d \ leq 16 $ and derive a closed formula for the leading betti numbers $ b _ i ( m _ d ) $ with $ d \ geq 6 $ and $ i \ leq 4d - 22 $. we also propose a conjectural formula for the leading betti numbers $ b _ i ( m _ d ) $ with $ d \ geq 4 $ and $ i \ leq 6d - 20 $. in the appendix ( by m. moreira ), a more general conjecture concerning the higher range betti numbers of $ m _ { d } $ is presented, along with another conjecture that involves refinements from the perverse / chern filtration.
|
arxiv:2501.05622
|
reversible cellular automata ( rca ) are a physics - like model of computation consisting of an array of identical cells, evolving in discrete time steps by iterating a global evolution g. further, g is required to be shift - invariant ( it acts the same everywhere ), causal ( information cannot be transmitted faster than some fixed number of cells per time step ), and reversible ( it has an inverse which verifies the same requirements ). an important, though only recently studied special case is that of time - symmetric cellular automata ( tsca ), for which g and its inverse are related via a local operation. in this note we revisit the question of the block representation of rca, i. e. we provide a very simple proof of the existence of a reversible circuit description implementing g. this operational, bottom - up description of g turns out to be time - symmetric, suggesting interesting connections with tsca. indeed we prove, using a similar technique, that a wide class of them admit an exact block representation ( ebr ), i. e. one which does not increase the state space.
|
arxiv:1201.5529
|
we numerically simulate, in both the forced and decay regimes, a fourth - order nonlinear diffusion equation derived from the kinetic equation of gravitational wave turbulence in the limit of strongly local quartic interactions. when a forcing is applied to an intermediate wavenumber $ k _ i $, we observe a dual cascade of energy and wave action. in the stationary state, the associated flux ratio is proportional to $ k _ i $, and the kolmogorov - zakharov spectra are recovered. in decaying turbulence, the study reveals that the wave action spectrum can extend to wavenumbers greater than the initial excitation $ k _ i $ with constant negative flux, while the energy flux is positive with a power law dependence in $ k $. this leads to an unexpected result : a single inertial range with a kolmogorov - zakharov wave action spectrum extending progressively to wavenumbers larger than $ k _ i $. we also observe a wave action decay in time in $ t ^ { - 1 / 3 } $ while the front of the energy spectrum progresses according to a $ t ^ { 1 / 3 } $ law. these properties can be understood with simple theoretical arguments.
|
arxiv:2501.17023
|
this paper proposes a non - parallel many - to - many voice conversion ( vc ) method using a variant of the conditional variational autoencoder ( vae ) called an auxiliary classifier vae ( acvae ). the proposed method has three key features. first, it adopts fully convolutional architectures to construct the encoder and decoder networks so that the networks can learn conversion rules that capture time dependencies in the acoustic feature sequences of source and target speech. second, it uses an information - theoretic regularization for the model training to ensure that the information in the attribute class label will not be lost in the conversion process. with regular cvaes, the encoder and decoder are free to ignore the attribute class label input. this can be problematic since in such a situation, the attribute class label will have little effect on controlling the voice characteristics of input speech at test time. such situations can be avoided by introducing an auxiliary classifier and training the encoder and decoder so that the attribute classes of the decoder outputs are correctly predicted by the classifier. third, it avoids producing buzzy - sounding speech at test time by simply transplanting the spectral details of the input speech into its converted version. subjective evaluation experiments revealed that this simple method worked reasonably well in a non - parallel many - to - many speaker identity conversion task.
|
arxiv:1808.05092
|
artefacts compromise clinical decision - making in the use of medical time series. pulsatile waveforms offer probabilities for accurate artefact detection, yet most approaches rely on supervised manners and overlook patient - level distribution shifts. to address these issues, we introduce a generalised label - free framework, genclean, for real - time artefact cleaning and leverage an in - house dataset of 180, 000 ten - second arterial blood pressure ( abp ) samples for training. we first investigate patient - level generalisation, demonstrating robust performances under both intra - and inter - patient distribution shifts. we further validate its effectiveness through challenging cross - disease cohort experiments on the mimic - iii database. additionally, we extend our method to photoplethysmography ( ppg ), highlighting its applicability to diverse medical pulsatile signals. finally, its integration into icm +, a clinical research monitoring software, confirms the real - time feasibility of our framework, emphasising its practical utility in continuous physiological monitoring. this work provides a foundational step toward precision medicine in improving the reliability of high - resolution medical time series analysis
|
arxiv:2504.21209
|
convolutional pose machine is a popular neural network architecture for articulated pose estimation. in this work we explore its empirical receptive field and realize, that it can be enhanced with integration of a global context. to do so u - shaped context module is proposed and compared with the pyramid pooling and atrous spatial pyramid pooling modules, which are often used in semantic segmentation domain. the proposed neural network achieves state - of - the - art accuracy with 87. 9 % pckh for single - person pose estimation on the look into person dataset. a smaller version of this network runs more than 160 frames per second while being just 2. 9 % less accurate. generalization of the proposed approach is tested on the mpii benchmark and shown, that it faster than hourglass - based networks, while provides similar accuracy. the code is available at https : / / github. com / opencv / openvino _ training _ extensions / tree / develop / pytorch _ toolkit / human _ pose _ estimation.
|
arxiv:1906.04104
|
three - coupled chains of quarter - filled hubbard model with dimerization have been studied for periodic boundary conditions. by use of a renormalization group method, it is found that the interchain hopping is renormalized to zero leading to confinement when charge gap becomes larger than the effective interchain hopping energy. such a result of confinement is compared with that of two - coupled chains.
|
arxiv:cond-mat/0005138
|
in the rapidly evolving landscape of artificial intelligence, multi - modal large language models are emerging as a significant area of interest. these models, which combine various forms of data input, are becoming increasingly popular. however, understanding their internal mechanisms remains a complex task. numerous advancements have been made in the field of explainability tools and mechanisms, yet there is still much to explore. in this work, we present a novel interactive application aimed towards understanding the internal mechanisms of large vision - language models. our interface is designed to enhance the interpretability of the image patches, which are instrumental in generating an answer, and assess the efficacy of the language model in grounding its output in the image. with our application, a user can systematically investigate the model and uncover system limitations, paving the way for enhancements in system capabilities. finally, we present a case study of how our application can aid in understanding failure mechanisms in a popular large multi - modal model : llava.
|
arxiv:2404.03118
|
divergence - free lie algebras ( also known as the special lie algebras of cartan type ) are lie algebras of volume - preserving transformation groups. they are simple in generic case. dokovic and zhao found a certain graded generalization of them. in this paper, we classify all the irreducible and indecomposable multiplicity - free modules of the simple generalized divergence - free lie algebras.
|
arxiv:1012.3626
|
this paper is devoted to investigate $ f ( r ) $ gravity using noether symmetry approach. for this purpose, we consider friedmann robertson - walker ( frw ) universe and spherically symmetric spacetimes. the noether symmetry generators are evaluated for some specific choice of $ f ( r ) $ models in the presence of gauge term. further, we calculate the corresponding conserved quantities in each case. moreover, the importance and stability criteria of these models are discussed.
|
arxiv:1207.1008
|
red supergiants ( rsgs ) are cool and evolved massive stars exhibiting enhanced mass loss compared to their main sequence phase, affecting their evolution and fate. however, the theory of the wind - driving mechanism is not well - established and the metallicity dependence has not been determined. we aim to uniformly measure the mass - loss rates of large samples of rsgs in different galaxies with $ - 0. 7 \ lesssim [ z ] \ lesssim0 $ to investigate whether there is a potential correlation with metallicity. we collected photometry from the ultraviolet to the mid - infrared for all our rsg candidates to construct their spectral energy distribution ( sed ). our final sample includes 893 rsg candidates in the small magellanic cloud ( smc ), 396 in ngc 6822, 527 in the milky way, 1425 in m31, and 1854 in m33. each sed was modelled using the radiative transfer code dusty under the same assumptions to derive the mass - loss rate. the mass - loss rates range from approximately $ 10 ^ { - 9 } \ m _ { \ odot } $ yr $ ^ { - 1 } $ to $ 10 ^ { - 5 } \ m _ { \ odot } $ yr $ ^ { - 1 } $ with an average value of $ 1. 5 \ times10 ^ { - 7 } \ m _ { \ odot } $ yr $ ^ { - 1 } $. we provided a new mass - loss rate relation as a function of luminosity and effective temperature for both the smc and milky way and compared our mass - loss rates with those derived in the large magellanic cloud ( lmc ). the turning point in the mass - loss rate vs. luminosity relation differs by around 0. 2 dex between the lmc and smc. the mass - loss rates of the galactic rsgs at $ \ log ( l / l _ \ odot ) < 4. 5 $ were systematically lower than those determined in the other galaxies, possibly due to uncertainties in the interstellar extinction. we found 30 - 40 % of the rsgs not to have any dust. the results for m31 and m33 are inconclusive because of source blending at distances above 0. 5 mpc given the resolution of spitzer. overall, we found similar mass - loss rates among the galaxies, indicating no strong correlation with metallicity.
|
arxiv:2503.05876
|
recall that a triangular hopf algebra a is said to have the chevalley property if the tensor product of any two simple a - modules is semisimple, or, equivalently, if the radical of a is a hopf ideal. there are two reasons to study this class of triangular hopf algebras : first, it contains all known examples of finite - dimensional triangular hopf algebras ; second, it can be, in a sense, " completely understood ". namely, it was shown in our previous work with andruskiewitsch that any finite - dimensional triangular hopf algebra with the chevalley property is obtained by twisting of a finite - dimensional triangular hopf algebra with r - matrix of rank at most 2 which, in turn, is obtained by " modifying " the group algebra of a finite supergroup. this provides a classification of such hopf algebras. the goal of this paper is to make this classification more effective and explicit, i. e. to parameterize isomorphism classes of finite - dimensional triangular hopf algebras with the chevalley property by group - theoretical objects, similarly to how it was done in our previous work in the semisimple case. this is achieved in theorem 2. 2, where these classes are put in bijection with certain septuples of data. in the semisimple case, the septuples reduce to the quadruples, and we recover the result of our previous paper. in the minimal triangular pointed case, we recover a classification theorem from a previous paper of the second author.
|
arxiv:math/0101049
|
we modify a stellar structure code to estimate the effect upon the main sequence of the accretion of weakly interacting dark matter onto stars and its subsequent annihilation. the effect upon the stars depends upon whether the energy generation rate from dark matter annihilation is large enough to shut off the nuclear burning in the star. main sequence wimp burners look much like protostars moving on the hayashi track, although they are in principle completely stable. we make some brief comments about where such stars could be found, how they might be observed and more detailed simulations which are currently in progress. finally we comment on whether or not it is possible to link the paradoxically young ob stars found at the galactic centre with wimp burners.
|
arxiv:0710.3396
|
january 2021 report in melbourne ' s herald sun noted an increased number of reports for dumped rubbish. = = europe = = = = = denmark = = = = = = = government - led initiatives = = = = in 2002, mindlab an innovation public sector service design group was established by the danish ministries of business and growth, employment, and children and education. mindlab was one of the world ' s first public sector design innovation labs and their work inspired the proliferation of similar labs and user - centered design methodologies deployed in many countries worldwide. the design methods used at mindlab are typically an iterative approach of rapid prototyping and testing to evolve not just their government projects, but also government organizational structure using ethnographic - inspired user research, creative ideation processes, and visualization and modeling of service prototypes. in denmark, design within the public sector has been applied to a variety of projects including rethinking copenhagen ' s waste management, improving social interactions between convicts and guards in danish prisons, transforming services in odense for mentally disabled adults and more. = = = estonia = = = = = = = government - led initiatives = = = = the process of digitalization in estonia began in 2002, when local and central governments began building an infrastructure that allowed autonomous and interconnected data. that same year in 2002, estonia launched a national id system that was fully digitalized and paired with digital signatures. the national id system allowed estonians to pay taxes online, vote online, do online banking, access their health care records, as well as process 99 % of estonian public services online 24 hours a day, seven days. estonia is well known internationally for its e - voting system. internet voting ( where citizens vote remotely with their own equipment ) was piloted in estonia in 2005 and has been in use since then. as of 2016, estonia ' s internet voting system has been implemented in three local elections, two european parliament elections, and three parliamentary elections. in 2007, estonia faced a politically motivated, large cyber attack which damaged most of the country ' s digital infrastructure, and as a result became the home of nato cyber defense centre of excellence. the national security response was updated and approved in 2010 in response to the cyber attacks, and recognizes the growing threat of cyber crime in estonia. in 2014, estonia launched the e - residency, which allowed users to create and manage a location independent business online from anywhere in the world. that was followed by an immigration visa for digital nomads, which was a novel way of approaching immigration policy
|
https://en.wikipedia.org/wiki/Civic_technology
|
localization and mapping are key capabilities for self - driving vehicles. in this paper, we build on kimera and extend it to use multiple cameras as well as external ( eg wheel ) odometry sensors, to obtain accurate and robust odometry estimates in real - world problems. additionally, we propose an effective scheme for closing loops that circumvents the drawbacks of common alternatives based on the perspective - n - point method and also works with a single monocular camera. finally, we develop a method for dense 3d mapping of the free space that combines a segmentation network for free - space detection with a homography - based dense mapping technique. we test our system on photo - realistic simulations and on several real datasets collected on a car prototype developed by the ford motor company, spanning both indoor and outdoor parking scenarios. our multi - camera system is shown to outperform state - of - the art open - source visual - inertial - slam pipelines ( vins - fusion, orb - slam3 ), and exhibits an average trajectory error under 1 % of the trajectory length across more than 8km of distance traveled ( combined across all datasets ). a video showcasing the system is available at : youtu. be / h8cpzdpxoi8.
|
arxiv:2304.13182
|
in this work, we explore a change of paradigm to build precomputed radiance transfer ( prt ) methods in a data - driven way. this paradigm shift allows us to alleviate the difficulties of building traditional prt methods such as defining a reconstruction basis, coding a dedicated path tracer to compute a transfer function, etc. our objective is to pave the way for machine learned methods by providing a simple baseline algorithm. more specifically, we demonstrate real - time rendering of indirect illumination in hair and surfaces from a few measurements of direct lighting. we build our baseline from pairs of direct and indirect illumination renderings using only standard tools such as singular value decomposition ( svd ) to extract both the reconstruction basis and transfer function.
|
arxiv:2206.13112
|
quantum information technologies provide promising applications in communication and computation, while machine learning has become a powerful technique for extracting meaningful structures in ' big data '. a crossover between quantum information and machine learning represents a new interdisciplinary area stimulating progresses in both fields. traditionally, a quantum state is characterized by quantum state tomography, which is a resource - consuming process when scaled up. here we experimentally demonstrate a machine - learning approach to construct a quantum - state classifier for identifying the separability of quantum states. we show that it is possible to experimentally train an artificial neural network to efficiently learn and classify quantum states, without the need of obtaining the full information of the states. we also show how adding a hidden layer of neurons to the neural network can significantly boost the performance of the state classifier. these results shed new light on how classification of quantum states can be achieved with limited resources, and represent a step towards machine - learning - based applications in quantum information processing.
|
arxiv:1712.00456
|
we discuss the first results from two successful simulations of galaxy formation within a cosmological volume. with over 2000 large objects forming in each we have sufficient numbers to reliably produce both galaxy correlation and luminosity functions. we find that the observed galaxy counts are well fitted by these models and that the galaxies display an almost un - evolving correlation function back to a redshift of 3 which closely resembles the featureless observed form and amplitude.
|
arxiv:astro-ph/9906032
|
from the quark confinement idea, we conjecture that the quarks compose colorless particles ( uud and udd - the lee particles ) and then the lee particles construct a body center cubic lattice in the vacuum. in terms of the energy band theory, from the symmetries of the body center cubic periodic field, we deduce the baryon spectrum ( with a united mass formula ) using only 2 flavored quarks u and d. we also predict some new baryons : $ \ lambda ^ { 0 } $ ( 2559 ), $ \ lambda _ { c } ^ { + } $ ( 6659 ), $ \ lambda _ { b } ^ { 0 } $ ( 10159 ).... the experiments to find the long lifetime baryon $ \ lambda ^ { 0 } $ ( 2559 ) should be done first.
|
arxiv:hep-ph/0012239
|
this paper investigates how secure information sharing with external vendors can be achieved in an industrial internet of things ( iiot ). it also identifies necessary security requirements for secure information sharing based on identified security challenges stated by the industry. the paper then proposes a roadmap for improving security in iiot which investigates both short - term and long - term solutions for protecting iiot devices. the short - term solution is mainly based on integrating existing good practices. the paper also outlines a long term solution for protecting iiot devices with fine - grained access control for sharing data between external entities that would support cloud - based data storage.
|
arxiv:1601.04301
|
we consider equally - weighted cantor measures $ \ mu _ { q, b } $ arising from iterated function systems of the form $ { b ^ { - 1 } ( x + i ) } $, $ i = 0, 1,..., q - 1 $, where $ q < b $. we classify the $ ( q, b ) $ so that they have infinitely many mutually orthogonal exponentials in $ l ^ 2 ( \ mu _ { q, b } ) $. in particular, if $ q $ divides $ b $, the measures have a complete orthogonal exponential system and hence spectral measures. we then characterize all the maximal orthogonal sets $ \ lambda $ when $ q $ divides $ b $ via a maximal mapping on the $ q - $ adic tree in which all elements in $ \ lambda $ are represented uniquely in finite $ b - $ adic expansions and we can separate the maximal orthogonal sets into two types : regular and irregular sets. for a regular maximal orthogonal set, we show that its completeness in $ l ^ 2 ( \ mu _ { q, b } ) $ is crucially determined by the certain growth rate of non - zero digits in the tail of the $ b - $ adic expansions of the elements. furthermore, we exhibit complete orthogonal exponentials with zero beurling dimensions. these examples show that the technical condition in theorem 3. 5 of \ cite { [ dhsw ] } cannot be removed. for an irregular maximal orthogonal set, we show that under some condition, its completeness is equivalent to that of the corresponding regularized mapping.
|
arxiv:1209.4386
|
an approach to use the method of laplace transform for the perturbative solution of the schr \ " { o } dinger equation at any order of the perturbation for a system of $ n $ qubits coupled to a cavity with $ n $ photons is suggested. we investigate the dynamics of a system of $ n $ superconducting qubits coupled to a common resonator with time - dependent coupling. to account for the contribution of the dynamical lamb effect to the probability of excitation of the qubit, we consider counter - rotating terms in the qubit - photon interaction hamiltonian. as an example, we illustrate the method for the case of two qubits coupled to a common cavity. the perturbative solutions for the probability of excitation of the qubit show excellent agreement with the numerical calculations.
|
arxiv:1809.02881
|
exotic spin - multipolar ordering in spin transition metal insulators has so far eluded unambiguous experimental observation. a less studied, but perhaps more feasible fingerprint of multipole character emerges in the excitation spectrum in the form of quadrupolar transitions. such multipolar excitations are desirable as they can be manipulated with the use of light or electric field and can be captured by means of conventional experimental techniques. here we study single crystals of multiferroic sr $ _ 2 $ coge $ _ 2 $ o $ _ 7 $, and show that due to its nearly isotropic nature a purely quadrupolar bimagnon mode appears in the electron spin resonance ( esr ) spectra. this non - magnetic spin - excitation couples to the electric field of the light and becomes observable for a specific experimental configuration, in full agreement with a theoretical analysis of the selection rules.
|
arxiv:1702.04158
|
we discuss the lagrangian - eulerian framework for hydrodynamic models and provide a proof of lipschitz dependence of solutions on initial data in path space. the paper presents a corrected version of the result in \ cite { c1 }.
|
arxiv:1812.00039
|
estimating the direction of arrival ( doa ) of sources is an important problem in aerospace and vehicular communication, localization and radar. in this paper, we consider a challenging multi - source doa estimation task, where the receiving antenna array is composed of non - coherent sub - arrays, i. e., sub - arrays that observe different unknown phase shifts at every snapshot ( e. g., due to waiving the demanding synchronization of local oscillators across the entire array ). we formulate this problem as the reconstruction of joint sparse and low - rank matrices, and solve the problem ' s convex relaxation. to scale the optimization complexity with the number of snapshots better than general - purpose solvers, we design an optimization scheme, based on integrating the alternating direction method of multipliers and the accelerated proximal gradient techniques, that exploits the structure of the problem. while the doas can be estimated from the solution of the aforementioned convex problem, we further show how an improvement is obtained if, instead, one estimates from this solution only the sub - arrays ' phase shifts. this is done using another, computationally - light, convex relaxation that is practically tight. using the estimated phase shifts, " phase - corrected " observations are created and a final plain ( " coherent " ) doa estimation method can be applied. numerical experiments show the performance advantages of the proposed strategies over existing methods.
|
arxiv:2202.07781
|
the ability to partially oxidize methane at low temperatures and pressures would have important environmental and economic applications. although methane oxidation on gold nanoparticles has been observed experimentally, our density functional theory ( dft ) calculations indicate neither ch4, ch3, nor h adsorb on a neutral gold nanoparticle. however, by positively charging gold nanoparticles, e. g. through charge transfer to the tio2 substrate, ch4 binding increases while o2 binding remains relatively unchanged. we demonstrate that ch4 adsorption is via bonding with the metal s levels. this holds from small gold clusters ( au2 ) to large gold nanoparticles ( au201 ), and for all fcc transition metal dimers. these results provide the chemical understanding necessary to tune the catalytic activity of metal nanoparticles for the partial oxidation of methane under delicate conditions.
|
arxiv:1308.5266
|
we measured temperatures, gravities, and masses for a large sample of blue horizontal branch stars in omega centauri, comparing the results with theoretical expectations for canonical and he - enriched stars, and with previous measurements in three other clusters. the measured gravities of omega cen stars are systematically lower than canonical models, in agreement with expectations for he - enriched stars, and contrary to that observed in the comparison clusters. however, the derived masses are unrealistically too low as well. this cannot be explained by low gravities alone, nor by any of the other parameters entering in the calculation. we find that the same stars are not brighter than their analogs in the other clusters, contrary to the expectations of the he - enrichment scenario. the interpretation of the results is thus not straightforward, but they reveal an intrinsic, physical difference between hb stars in omega cen and in the three comparison clusters.
|
arxiv:1107.5601
|
two - dimensional ( 2d ) semiconductors have demonstrated great potential for next - generation electronics and optoelectronics. however, the current 2d semiconductors suffer from intrinsically low carrier mobility at room temperature, which significantly limits its applications. here we discover a variety of new 2d semiconductors with mobility one order of magnitude higher than the current ones. the discovery is made by developing effective descriptors for high - throughput computationally screening of the 2d materials database, followed by using state - of - the - art first principles method to accurately calculate the mobility. further analyses attribute their exceptional mobilities to small effective mass, high sound velocity, high optical phonon frequency, small ratio of born charge vs. polarizability, and / or weak electron - phonon coupling. our work opens up new materials to realize high device performance and / or exotic physics that are difficult to achieve previously, and improves the understanding of the carrier transport mechanism.
|
arxiv:2208.10663
|
many types of pairwise interaction take the form of a fixed set of nodes with edges that appear and disappear over time. in the case of discrete - time evolution, the resulting evolving network may be represented by a time - ordered sequence of adjacency matrices. we consider here the issue of representing the system as a single, higher dimensional block matrix, built from the individual time - slices. we focus on the task of computing network centrality measures. from a modeling perspective, we show that there is a suitable block formulation that allows us to recover dynamic centrality measures respecting time ' s arrow. from a computational perspective, we show that the new block formulation leads to the design of more effective numerical algorithms.
|
arxiv:1511.07305
|
in a recent paper, hod proved that spherically symmetric dirichlet reflecting compact stars cannot support static nonminimally coupled scalar fields. in the present paper, we study the validity of no hair theorems for compact stars with neumann surface boundary conditions. we find that neumann compact stars cannot support static massive scalar field hairs with a generic dimensionless nonminimal coupling parameter.
|
arxiv:1903.01713
|
we revisit sidewise dispersion relations as a method to relate the nucleon off - shell form factor to observable quantities, namely the meson - nucleon scattering phase shifts. it is shown how for meson - nucleon scattering a redefinition of the intermediate fields leaves the scattering amplitude invariant, but changes the behavior of the off - shell form factor as expressed through dispersion relations, thus showing representation dependence. we also employ a coupled - channel unitary model to test the validity of approximations concerning the influence of inelastic channels in the sidewise dispersion relation method.
|
arxiv:nucl-th/9603031
|
we establish convergence of spectra of neumann laplacian in a thin neighborhood of a branching 2d structure in 3d to the spectrum of an appropriately defined operator on the structure itself. this operator is a 2d analog of the well known by now quantum graphs. as in the latter case, such considerations are triggered by various physics and engineering applications.
|
arxiv:1908.06222
|
simultaneous strong coherent pumping of the two transitions of a v - level atom with very differentdecay rates has been predicted to create almost perfect inversion on the narrower transition. usingthe example of the blue and red transitions in strontium we show that for suitable operatingconditions the corresponding resonant gain can be used to continuously operate a laser on thenarrow transition. in particular, for a strong detuning of the pump field with respect to the narrowtransition, coherent laser emission occurs close to the bare atomic transition frequency exhibitingonly a negligible contribution from coherent pump light scattered into the lasing mode. calculations of the cavity output spectrum show that the resulting laser linewidth can get muchsmaller than the bandwidth of the pump light and even the natural linewidth of the narrow atomictransition. its frequency is closely tied to the atomic transition frequency for properly chosen atomnumbers. simulations including atomic motionshow doppler cooling on the strong transitionwith minor motion heating on the lasing transition, so that continuous laser operation in thepresence of a magneto - optical trap should be possible with current experimental technology.
|
arxiv:2007.12522
|
in two articles by barthel, brasselet, fieseler and kaup, and, bressler and lunts, a combinatorial theory of intersection cohomology and perverse sheaves has been developed on fans. in the first one, one tried to present everything on an elementary level, using only some commutative algebra and no derived categories. there remained two major gaps : first of all the hard lefschetz theorem was only conjectured and secondly the intersection product seemed to depend on some non - canonical choices. meanwhile the hard lefschetz theorem has been proved by karu. the proof relies heavily on the intersection product, since what finally has to be shown are the hodge - riemann relations. in fact here again choices enter : the intersection product is induced from the intersection product on some simplicial subdivision via a direct embedding of the corresponding intersection cohomology sheaves, a fact, which makes the argumentation quite involved. in a recent paper by bressler and lunts, one shows by a detailed analysis that eventually all possible choices do not affect the definition of the pairing. our goal here is the same, but we shall try to follow the spirit of the first cited paper avoiding the formalism of derived categories. for perverse sheaves we define their dual sheaf and check that the intersection cohomology sheaf is self - dual in a natural way.
|
arxiv:math/0306344
|
in this paper the experimental demonstration of a silicon - on - insulator reflective arrayed waveguide grating ( r - awg ) is reported. the device employs one sagnac loop mirror per arm in the array, built with a 1x2 input / outputs, 50 : 50 splitting ratio, multimode interference coupler, for total reflection. the spectral responses obtained are compared to those of regular awgs fabricated in the same die.
|
arxiv:1403.7706
|
we review important ideas on nuclear and quark matter description on the basis of high - temperature field theory concepts, like resummation, dimensional reduction, interaction scale separation and spectral function modification in media. statistical and thermodynamical concepts are spotted in the light of these methods concentrating on the - partially still open - problems of the hadronization process.
|
arxiv:1610.09973
|
there are various quantum chemical approaches for an ab initio description of transfer integrals within the framework of marcus theory in the context of electron transfer reactions. in our article we aim to calculate transfer integrals in redox - active single molecule junctions, where we focus on the coherent tunneling limit with the metal leads taking the position of donor and acceptor and the molecule acting as a transport mediating bridge. this setup allows us to derive a conductance, which can be directly compared with recent results from a non - equilibrium green ' s function approach. compared with purely molecular systems we face additional challenges due to the metallic nature of the leads, which rules out some of the common techniques, and due to their periodicity, which requires { \ bf k } space integration. we present three different methods, all based on density functional theory, for calculating the transfer integral under these constraints, which we benchmark on molecular test systems from the relevant literature. we also discuss manybody effects and apply all three techniques to a junction with a ruthenium complex in different oxidation states.
|
arxiv:1312.5607
|
we explore the thermodynamics and the underlying kinetics of the van der waals type phase transition of reissner - nordstr \ " { o } m anti - de sitter ( rnads ) black holes based on the free energy landscape. we show that the thermodynamic stabilities of the three branches of the rnads black holes are determined by the underlying free energy landscape topography. we suggest that the large ( small ) rnads black hole can have the probability to switch to the small ( large ) black hole due to the thermal fluctuation. such a state switching process under the thermal fluctuation is taken as a stochastic process and the associated kinetics can be described by the probabilistic fokker - planck equation. we obtained the time dependent solutions for the probabilistic evolution by numerically solving fokker - planck equation with the reflecting boundary conditions. we also investigated the first passage process which describes how fast a system undergoes a stochastic process for the first time. the distributions of the first passage time switching from small ( large ) to large ( small ) black hole and the corresponding mean first passage time as well as its fluctuations at different temperatures are studied in detail. we conclude that the mean first passage time and its fluctuations are related to the free energy landscape topography through barrier heights and temperatures.
|
arxiv:2008.00495
|
it is well known that many open - released foundational diffusion models have difficulty in generating images that substantially depart from average brightness, despite such images being present in the training data. this is due to an inconsistency : while denoising starts from pure gaussian noise during inference, the training noise schedule retains residual data even in the final timestep distribution, due to difficulties in numerical conditioning in mainstream formulation, leading to unintended bias during inference. to mitigate this issue, certain $ \ epsilon $ - prediction models are combined with an ad - hoc offset - noise methodology. in parallel, some contemporary models have adopted zero - terminal snr noise schedules together with $ \ mathbf { v } $ - prediction, which necessitate major alterations to pre - trained models. however, such changes risk destabilizing a large multitude of community - driven applications anchored on these pre - trained models. in light of this, our investigation revisits the fundamental causes, leading to our proposal of an innovative and principled remedy, called one more step ( oms ). by integrating a compact network and incorporating an additional simple yet effective step during inference, oms elevates image fidelity and harmonizes the dichotomy between training and inference, while preserving original model parameters. once trained, various pre - trained diffusion models with the same latent domain can share the same oms module.
|
arxiv:2311.15744
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.