Statistical Mechanics
New submissions
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New submissions for Fri, 19 Apr 24
- [1] arXiv:2404.11768 [pdf, ps, other]
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Title: Tensor-Networks-based Learning of Probabilistic Cellular Automata DynamicsComments: 9 pages, 7 figuresSubjects: Statistical Mechanics (cond-mat.stat-mech); Machine Learning (cs.LG); Quantum Physics (quant-ph)
Algorithms developed to solve many-body quantum problems, like tensor networks, can turn into powerful quantum-inspired tools to tackle problems in the classical domain. In this work, we focus on matrix product operators, a prominent numerical technique to study many-body quantum systems, especially in one dimension. It has been previously shown that such a tool can be used for classification, learning of deterministic sequence-to-sequence processes and of generic quantum processes. We further develop a matrix product operator algorithm to learn probabilistic sequence-to-sequence processes and apply this algorithm to probabilistic cellular automata. This new approach can accurately learn probabilistic cellular automata processes in different conditions, even when the process is a probabilistic mixture of different chaotic rules. In addition, we find that the ability to learn these dynamics is a function of the bit-wise difference between the rules and whether one is much more likely than the other.
- [2] arXiv:2404.12106 [pdf, other]
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Title: Landau-Lifschitz magnets: exact thermodynamics and transportComments: 4 pages, 2 figuresSubjects: Statistical Mechanics (cond-mat.stat-mech); Exactly Solvable and Integrable Systems (nlin.SI)
The classical Landau--Lifshitz equation -- the simplest model of a ferromagnet -- provides an archetypal example for studying transport phenomena. In one-spatial dimension, integrability enables the classification of the spectrum of linear and nonlinear modes. An exact characterization of finite-temperature thermodynamics and transport has nonetheless remained elusive. We present an exact description of thermodynamic equilibrium states in terms of interacting modes. This is achieved by retrieving the classical Landau--Lifschitz model through the semiclassical limit of the integrable quantum spin-$S$ anisotropic Heisenberg chain at the level of the thermodynamic Bethe ansatz description. In the axial regime, the mode spectrum comprises solitons with unconventional statistics, whereas in the planar regime we additionally find two special types of modes of radiative and solitonic type. The obtained framework paves the way for analytical study of unconventional transport properties: as an example we study the finite-temperature spin Drude weight, finding excellent agreement with Monte Carlo simulations.
- [3] arXiv:2404.12159 [pdf, other]
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Title: Localization in boundary-driven lattice modelsComments: 31 pagesSubjects: Statistical Mechanics (cond-mat.stat-mech)
Several systems may display an equilibrium condensation transition, where a finite fraction of a conserved quantity is spatially localized. The presence of two conservation laws may induce the emergence of such transition in an out-of-equilibrium setup, where boundaries are attached to two different and subcritical heat baths. We study this phenomenon in a class of stochastic lattice models, where the local energy is a general convex function of the local mass, mass and energy being both globally conserved in the isolated system. We obtain exact results for the nonequilibrium steady state (spatial profiles, mass and energy currents, Onsager coefficients) and we highlight important differences between equilibrium and out-of-equilibrium condensation.
Cross-lists for Fri, 19 Apr 24
- [4] arXiv:2404.10074 (cross-list from cond-mat.str-el) [pdf, other]
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Title: Nano-welding of quantum spin-$1/2$ chains at minimal dissipationComments: 13 pages, 6 figuresSubjects: Strongly Correlated Electrons (cond-mat.str-el); Statistical Mechanics (cond-mat.stat-mech); Quantum Physics (quant-ph)
We consider the optimal control of switching on a coupling term between two quantum many-body systems. Specifically, we (i) quantify the energetic cost of establishing a weak junction between two quantum spin-$1/2$ chains in finite time $\tau$ and (ii) identify the energetically optimal protocol to realize it. For linear driving protocols, we find that for long times the excess (irreversible) work scales as $\tau^{-\eta}$, where $\eta=1, 2$ or a nonuniversal number depending on the phase of the chains. Interestingly, increasing a $J_z$ anisotropy in the chains suppresses the excess work thus promoting quasi-adiabaticity. The general optimal control problem is solved, employing a Chebyshev ansatz. We find that the optimal control protocol is intimately sensitive to the chain phases.
- [5] arXiv:2404.11360 (cross-list from quant-ph) [pdf, other]
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Title: Open-system eigenstate thermalization in a noninteracting integrable modelComments: 13 pages, 12 figuresSubjects: Quantum Physics (quant-ph); Statistical Mechanics (cond-mat.stat-mech)
We study thermalization in isolated quantum systems from an open quantum systems perspective. We argue that for a small system connected to a macroscopic bath, the system observables are thermal if the combined system-bath configuration is in an eigenstate of its Hamiltonian, even for fully integrable models (unless thermalization is suppressed by localization due to strong coupling). We illustrate our claim for a single fermionic level coupled to a noninteracting fermionic bath. We further show that upon quenching the system Hamiltonian, the system occupancy relaxes to the thermal value corresponding to the new Hamiltonian. Finally, we demonstrate that system thermalization also arises for a system coupled to a bath initialized in a typical eigenstate of its Hamiltonian. Our findings show that chaos and nonintegrability are not the sole drivers of thermalization and complementary approaches are needed to offer a more comprehensive understanding of how statistical mechanics emerges.
- [6] arXiv:2404.11649 (cross-list from cond-mat.dis-nn) [pdf, other]
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Title: Stark Many-Body Localisation Under Periodic DrivingSubjects: Disordered Systems and Neural Networks (cond-mat.dis-nn); Statistical Mechanics (cond-mat.stat-mech)
We study stability of localisation under periodic driving in many-body Stark systems. We find that localisation is stable except near special resonant frequencies, where resonances cause delocalisation. We provide approximate analytical arguments and numerical evidence in support of these results. This shows that disorder-free broken ergodicity is stable to driving, opening up the way to studying nonequilibrium driven physics in a novel setting.
- [7] arXiv:2404.11674 (cross-list from hep-lat) [pdf, other]
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Title: Practical applications of machine-learned flows on gauge fieldsAuthors: Ryan Abbott, Michael S. Albergo, Denis Boyda, Daniel C. Hackett, Gurtej Kanwar, Fernando Romero-López, Phiala E. Shanahan, Julian M. UrbanComments: 9 pages, 5 figures, proceedings of the 40th International Symposium on Lattice Field Theory (Lattice 2023)Subjects: High Energy Physics - Lattice (hep-lat); Statistical Mechanics (cond-mat.stat-mech); Machine Learning (cs.LG)
Normalizing flows are machine-learned maps between different lattice theories which can be used as components in exact sampling and inference schemes. Ongoing work yields increasingly expressive flows on gauge fields, but it remains an open question how flows can improve lattice QCD at state-of-the-art scales. We discuss and demonstrate two applications of flows in replica exchange (parallel tempering) sampling, aimed at improving topological mixing, which are viable with iterative improvements upon presently available flows.
- [8] arXiv:2404.11701 (cross-list from cond-mat.dis-nn) [pdf, ps, other]
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Title: Axial, Planar-Diagonal, Body-Diagonal Fields on the Cubic-Spin Spin Glass in d=3: A Plethora of Ordered Phases under Finite FieldsComments: 7 pages, 4 figures, 12 phase diagrams, 1 tableSubjects: Disordered Systems and Neural Networks (cond-mat.dis-nn); Statistical Mechanics (cond-mat.stat-mech)
A nematic phase, previously seen in the d=3 classical Heisenberg spin-glass system, occurs in the n-component cubic-spin spin-glass system, between the low-temperature spin-glass phase and the high-temperature disordered phase, for number of spin components n>=3, in spatial dimension d=3, thus constituting a liquid-crystal phase in a dirty (quenched-disordered) magnet. Furthermore, under application of a variety of uniform magnetic fields, a veritable plethora of phases are found. Under uniform magnetic fields, 15 different phases and two spin-glass phase diagram topologies, qualitatively different from the conventional spin-glass phase diagram topology, are seen. The chaotic rescaling behaviors and their Lyapunov exponents are calculated in each of these spin-glass phase diagram topologies. These results are obtained from renormalization-group calculations that are exact on the hierarchical lattice and, equivalently, approximate on the hypercubic spatial lattice. Axial, planar-diagonal, or body-diagonal finite-strength uniform fields are applied to n=2 and 3 component cubic-spin spin-glass systems in d=3.
- [9] arXiv:2404.11985 (cross-list from quant-ph) [pdf, other]
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Title: On the generic increase of observational entropy in isolated systemsComments: 6+5 pages, no figuresSubjects: Quantum Physics (quant-ph); Statistical Mechanics (cond-mat.stat-mech)
Observational entropy - a quantity that unifies Boltzmann's entropy, Gibbs' entropy, von Neumann's macroscopic entropy, and the diagonal entropy - has recently been argued to play a key role in a modern formulation of statistical mechanics. Here, relying on algebraic techniques taken from Petz's theory of statistical sufficiency and on a Levy-type concentration bound, we prove rigorous theorems showing how the observational entropy of a system undergoing a unitary evolution chosen at random tends to increase with overwhelming probability and to reach its maximum very quickly. More precisely, we show that for any observation that is sufficiently coarse with respect to the size of the system, regardless of the initial state of the system (be it pure or mixed), random evolution renders its state practically indistinguishable from the microcanonical distribution with a probability approaching one as the size of the system grows. The same conclusion holds not only for random evolutions sampled according to the unitarily invariant Haar distribution, but also for approximate 2-designs, which are thought to provide a more physically reasonable way to model random evolutions.
- [10] arXiv:2404.12100 (cross-list from quant-ph) [pdf, other]
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Title: Generic free fermions with nearest neighbour interactionsComments: 7 pages, 3 figuresSubjects: Quantum Physics (quant-ph); Quantum Gases (cond-mat.quant-gas); Statistical Mechanics (cond-mat.stat-mech)
Generic free fermions are free fermions with a single particle spectrum that satisfies the $q$ no resonance condition, i.e., where equal sums of single-particle energies are unique. This property guaranties that they have no degeneracies and gives them relaxation properties more similar to those of generic systems. In this article we provide a minimal example of a generic free fermionic model with nearest neighbour interactions -- a tight-binding model with complex hopping. Using some standard results from number theory we prove that this model fulfils the $q$ no resonance condition when the number of lattice sites is prime. Whenever this is not the case one can recover the $q$ no resonance condition by adding hopping terms between sites corresponding to the divisors of the number of sites. We further discuss its many-body spectral statistics and show that local probes -- like the ratio of consecutive level spacings -- look very similar to what is expected for the Poisson statistics. We however demonstrate that free fermion models can never have Poisson statistics with an analysis of the moments of the spectral form factor.
- [11] arXiv:2404.12118 (cross-list from quant-ph) [pdf, other]
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Title: Quantum thermodynamics of the spin-boson model using the principle of minimal dissipationSubjects: Quantum Physics (quant-ph); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Statistical Mechanics (cond-mat.stat-mech)
A recently developed approach to the thermodynamics of open quantum systems, on the basis of the principle of minimal dissipation, is applied to the spin-boson model. Employing a numerically exact quantum dynamical treatment based on the hierarchical equations of motion (HEOM) method, we investigate the influence of the environment on quantities such as work, heat and entropy production in a range of parameters which go beyond the weak-coupling limit and include both the non-adiabatic and the adiabatic regimes. The results reveal significant differences to the weak-coupling forms of work, heat and entropy production, which are analyzed in some detail.
- [12] arXiv:2404.12156 (cross-list from physics.hist-ph) [pdf, other]
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Title: The birth of StatPhys: The 1949 Florence conference at the juncture of post-WWII reconstruction of national and international physicsComments: 40 pagesSubjects: History and Philosophy of Physics (physics.hist-ph); Statistical Mechanics (cond-mat.stat-mech)
In spring 1949 about 70 physicists from eight countries met in Florence to discuss recent trends in statistical mechanics. This scientific gathering, co-organized by the Commission on Thermodynamics and Statistical Mechanics of the International Union of Pure and Applied Physics (IUPAP) and the Italian Physical Society (SIF), initiated a tradition of IUPAP-sponsored international conferences on statistical mechanics that lasts to this day. In 1977, when this conference series took the name of StatPhys, the foundational role of the Florence conference was recognized by retrospectively naming it StatPhys1. This paper examines the dual scientific and social significance of the conference, situating it in the broader contexts of the post-World War II reconstruction in Italian physics and of the revitalization of the international science organization. Through an analysis of IUPAP archives and Italian records, we illustrate how the event's success hinged on the aligned objectives of its organizers. Internationally, it was instrumental in defining the scientific and organizational foundations for the activities of IUPAP commissions during a critical phase of IUPAP's history, when the Union was resurging on the international stage post-interwar period inactivity. Nationally, the conference served as a cornerstone in SIF's strategy to re-establish Italian physics' international stature and to aid the domestic revitalization of physics through the internationalization of its activities, notably of its flagship journal, \textit{Il Nuovo Cimento}. This analysis not only sheds light on the conference's impact but also informs recent discussions in the history of science about the multiple roles of international scientific conferences.
- [13] arXiv:2404.12346 (cross-list from quant-ph) [pdf, other]
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Title: Quantum thermophoresisComments: 5 pages, 2 figuresSubjects: Quantum Physics (quant-ph); Statistical Mechanics (cond-mat.stat-mech)
Thermophoresis is the migration of a particle due to a thermal gradient. Here, we theoretically uncover the quantum version of thermophoresis. As a proof of principle, we analytically find a thermophoretic force on a trapped quantum particle having three energy levels in $\Lambda$ configuration. We then consider a model of N sites, each coupled to its first neighbors and subjected to a local bath at a certain temperature, so as to show numerically how quantum thermophoresis behaves with increasing delocalization of the quantum particle. We discuss how negative thermophoresis and the Dufour effect appear in the quantum regime.
- [14] arXiv:2404.12360 (cross-list from quant-ph) [pdf, other]
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Title: False vacuum decay and nucleation dynamics in neutral atom systemsAuthors: Siva Darbha, Milan Kornjača, Fangli Liu, Jan Balewski, Mark R. Hirsbrunner, Pedro Lopes, Sheng-Tao Wang, Roel Van Beeumen, Daan Camps, Katherine KlymkoComments: 14 pages, 8 figuresSubjects: Quantum Physics (quant-ph); Quantum Gases (cond-mat.quant-gas); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics - Theory (hep-th); Atomic Physics (physics.atom-ph)
False vacuum decay and nucleation offer the opportunity to study non-equilibrium dynamical phenomena in quantum many-body systems with confinement. Recent work has examined false vacuum decay in 1D ferromagnetic Ising spins and superfluids. In this paper, we study false vacuum nucleation dynamics in 1D antiferromagnetic neutral atom chains with Rydberg interactions, using both numerical simulations and analytic modeling. We apply a staggered local detuning field to generate the false and true vacuum states. Our efforts focus on two dynamical regimes: decay and annealing. In the first, we corroborate the phenomenological decay rate scaling and determine the associated parameter range for the decay process; in the second, we uncover and elucidate a procedure to anneal the false vacuum from the initial to the final system, with intermediate nucleation events. We further propose experimental protocols to prepare the required states and perform quenches on near-term neutral atom quantum simulators, examining the experimental feasibility of our proposed setup and parameter regime.
- [15] arXiv:2404.12371 (cross-list from quant-ph) [pdf, other]
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Title: Long-lived oscillations of false and true vacuum states in neutral atom systemsAuthors: Siva Darbha, Milan Kornjača, Fangli Liu, Jan Balewski, Mark R. Hirsbrunner, Pedro Lopes, Sheng-Tao Wang, Roel Van Beeumen, Katherine Klymko, Daan CampsComments: 14 pages, 5 figuresSubjects: Quantum Physics (quant-ph); Quantum Gases (cond-mat.quant-gas); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics - Theory (hep-th); Atomic Physics (physics.atom-ph)
Metastable false vacuum states arise in a range of quantum systems and can be observed in various dynamical scenarios, including decay, bubble nucleation, and long-lived oscillations. False vacuum phenomenology has been examined in quantum many-body systems, notably in 1D ferromagnetic Ising spin systems and superfluids. In this paper, we study long-lived oscillations of false and true vacuum states in 1D antiferromagnetic neutral atom chains with long-range Rydberg interactions. We use a staggered local detuning field to achieve confinement. Using theoretical and numerical models, we identify novel spectral signatures of quasiparticle oscillations distinct to antiferromagnetic neutral atom systems and interpret them using a classical energy model of deconfinement from Rydberg tails. Finally, we evaluate the experimental accessibility of our proposed setup on current neutral-atom platforms and discuss experimental feasibility and constraints.
Replacements for Fri, 19 Apr 24
- [16] arXiv:2303.17016 (replaced) [pdf, ps, other]
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Title: Fluctuation theorem for time-averaged workAuthors: Pierre NazéComments: 4 pages, 1 figureSubjects: Statistical Mechanics (cond-mat.stat-mech)
- [17] arXiv:2307.12960 (replaced) [pdf, other]
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Title: Role of interactions in non-equilibrium transformationsComments: 9 pages, 8 figures, Published versionJournal-ref: Phys. Rev. E 109, 044136 (2024)Subjects: Statistical Mechanics (cond-mat.stat-mech)
- [18] arXiv:2401.07274 (replaced) [pdf, other]
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Title: Corner transfer matrix renormalization group approach in the zoo of Archimedean latticesComments: 29 pages, 47 figures, final versionJournal-ref: Physical Review E 109, 045305 (2024)Subjects: Statistical Mechanics (cond-mat.stat-mech)
- [19] arXiv:2402.09936 (replaced) [pdf, other]
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Title: Conformally invariant free parafermionic quantum chains with multispin interactionsComments: 16 pages, 12 figuresJournal-ref: Phys. Rev. E, vol 109, 044138 (2024)Subjects: Statistical Mechanics (cond-mat.stat-mech)
- [20] arXiv:2402.18985 (replaced) [pdf, other]
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Title: Blume-Capel model analysis with microcanonical population annealing methodComments: 9 pages, 12 figuresSubjects: Statistical Mechanics (cond-mat.stat-mech)
- [21] arXiv:2404.04005 (replaced) [pdf, other]
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Title: The statistical mechanics and machine learning of the $α$-Rényi ensembleSubjects: Statistical Mechanics (cond-mat.stat-mech)
- [22] arXiv:2307.05995 (replaced) [pdf, ps, other]
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Title: Canonical partition function and distance dependent correlation functions of a quasi-one-dimensional system of hard disksComments: published in Journal of Molecular Liquids. arXiv admin note: substantial text overlap with arXiv:2206.05980Journal-ref: Journal of Molecular Liquids, Volume 387, 122572 (2023) and Journal of Molecular Liquids, Volume 393, 123639 (2024)Subjects: Disordered Systems and Neural Networks (cond-mat.dis-nn); Statistical Mechanics (cond-mat.stat-mech)
- [23] arXiv:2309.00455 (replaced) [pdf, other]
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Title: Ordering kinetics and steady states of XY-model with ferromagnetic and nematic interactionComments: 16 pages, 12 figuresJournal-ref: Journal of Physics: Condensed Matter; 36 (2024) 285101Subjects: Soft Condensed Matter (cond-mat.soft); Statistical Mechanics (cond-mat.stat-mech)
- [24] arXiv:2311.03939 (replaced) [pdf, other]
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Title: Computation of the Distribution of the Absorption Time of the Drifted Diffusion with Stochastic Resetting and Mixed Boundary ConditionsAuthors: Riccardo Turin, Juan Magalang, Javier Aguilar, Laetitia Colombani, Daniel Sanchez-Taltavull, Riccardo GattoSubjects: Computational Physics (physics.comp-ph); Statistical Mechanics (cond-mat.stat-mech); Probability (math.PR)
- [25] arXiv:2311.09292 (replaced) [pdf, other]
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Title: Full range spectral correlations and their spectral form factors in chaotic and integrable modelsComments: 19+6 pages, 13+10 figures. v2: new section II + new figuresSubjects: Quantum Physics (quant-ph); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics - Theory (hep-th); Mathematical Physics (math-ph); Chaotic Dynamics (nlin.CD)
- [26] arXiv:2401.16260 (replaced) [pdf, other]
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Title: Kinetic theory of motility induced phase separation for active Brownian particlesSubjects: Soft Condensed Matter (cond-mat.soft); Statistical Mechanics (cond-mat.stat-mech)
- [27] arXiv:2403.18523 (replaced) [pdf, other]
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Title: Exact Solution of Bipartite Fluctuations in One-Dimensional FermionsComments: 17 pages, 6 figuresSubjects: Quantum Gases (cond-mat.quant-gas); Statistical Mechanics (cond-mat.stat-mech); Quantum Physics (quant-ph)
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