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Related papers: Thermalization without chaos in harmonic systems

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In this paper, we numerically investigate whether quantum thermalization occurs during the time evolution induced by a non-local Hamiltonian whose spectra exhibit integrability. This non-local and integrable Hamiltonian is constructed by…

High Energy Physics - Theory · Physics 2025-08-28 Masataka Matsumoto , Shuta Nakajima , Masahiro Nozaki , Ryosuke Yoshii

In this paper, thermal transport in bond-disordered harmonic chains is revisited in detail using a nonequilibrium Green's function formalism. For strong bond disorder, thermal conductivity is independent of the system size. However, kinetic…

Statistical Mechanics · Physics 2021-10-25 Kiminori Hattori , Shohei Kumatoriya

Eigenstate thermalization has been numerically shown to occur for few-body observables in a wide range of nonintegrable models. For intensive sums of few-body observables, a weaker version of eigenstate thermalization known as weak…

Statistical Mechanics · Physics 2025-05-13 Patrycja Łydżba , Rafał Świętek , Marcin Mierzejewski , Marcos Rigol , Lev Vidmar

In classical statistical mechanics there is a clear correlation between relaxation to equilibrium and chaos. In contrast, for isolated quantum systems this relation is -- to say the least -- fuzzy. In this work we try to unveil the…

Quantum Physics · Physics 2015-01-26 Ignacio García-Mata , Augusto J. Roncaglia , Diego A. Wisniacki

The strong eigenstate thermalization hypothesis (ETH) provides a sufficient condition for thermalization and equilibration. Although it is expected to be hold in a wide class of highly chaotic theories, there are only a few analytic…

High Energy Physics - Theory · Physics 2026-01-19 Taishi Kawamoto

We consider isolated many-body quantum systems which do not thermalize, i.e., expectation values approach an (approximately) steady longtime limit which disagrees with the microcanonical prediction of equilibrium statistical mechanics. A…

Statistical Mechanics · Physics 2017-05-22 Ben N. Balz , Peter Reimann

We investigate the onset of thermalization and quantum chaos in finite one-dimensional gapped systems of hard-core bosons. Integrability in these systems is broken by next-nearest-neighbor repulsive interactions, which also generate a…

Statistical Mechanics · Physics 2010-07-12 Marcos Rigol , Lea F. Santos

It is usually expected and observed that non-integrable isolated quantum systems thermalize. However, for some non-integrable spin chain models, in a numerical study, initial states with oscillations that persisted for some time were found…

Quantum Physics · Physics 2024-09-10 Luis Fernando dos Prazeres , Thiago R. de Oliveira

It is "conventional wisdom" that the uncertainty of local temperature measurements on equilibrium systems diverges exponentially fast as their temperature $T$ drops to zero. In contrast, some exactly solvable models showcase a more benign…

Quantum Physics · Physics 2018-07-04 Karen V. Hovhannisyan , Luis A. Correa

Two identical finite quantum systems prepared initially at different temperatures, isolated from the environment, and subsequently brought into contact are demonstrated to relax towards Gibbs-like quasi-equilibrium states with a common…

Statistical Mechanics · Physics 2011-01-10 Alexey V. Ponomarev , Sergey Denisov , Peter Hänggi

We analyze the symmetries in an open quantum system composed by three coupled and detuned harmonic oscillators in the presence of a common heat bath. It is shown analytically how to engineer the couplings and frequencies of the system so as…

Quantum Physics · Physics 2015-05-19 Gonzalo Manzano , Fernando Galve , Roberta Zambrini

We propose a new mathematical tool for the study of transport properties of models for lattice vibrations in crystalline solids. By replication of dynamical degrees of freedom, we aim at a new dynamical system where the "local" dynamics can…

Mathematical Physics · Physics 2015-06-17 Jani Lukkarinen

We consider a particle in the approximation of a harmonic oscillator, coupled linearly to a field modeling an environment. The field is described by an infinite set of harmonic oscillators, and the system (particle--field) is considered in…

We study quantum quenches between integrable and nonintegrable hard-core boson models in the thermodynamic limit with numerical linked cluster expansions. We show that while quenches in which the initial state is a thermal equilibrium state…

Statistical Mechanics · Physics 2016-03-11 Marcos Rigol

An isolated quantum system is said to thermalize if ${\rm Tr} (A \rho(t)) \to {\rm Tr} (A \rho_{\rm eq})$ for time $t \to \infty$. Here $\rho(t)$ is the time-dependent density matrix of the system, $\rho_{\rm eq}$ is the time-independent…

Quantum Physics · Physics 2024-04-22 Hans A. Weidenmüller

We present a large-scale simulation of the three-dimensional and mean-field spin glasses down to a very low but finite temperature. We extrapolate pertinent observables, e.g., the disorder-averaged central weight to zero temperature,…

Disordered Systems and Neural Networks · Physics 2025-05-13 Wenlong Wang

In this paper we study the thermal equilibration of small bipartite Bose-Hubbard systems, both quantum mechanically and in mean-field approximation. In particular we consider small systems composed of a single-mode "thermometer" coupled to…

Quantum Physics · Physics 2019-06-26 Ralf Bürkle , James R. Anglin

We prove that spin chains weakly coupled to a large heat bath thermalize rapidly at any temperature for finite-range, translation-invariant commuting Hamiltonians, reaching equilibrium in a time which scales logarithmically with the system…

Quantum Physics · Physics 2023-05-12 Ivan Bardet , Ángela Capel , Li Gao , Angelo Lucia , David Pérez-García , Cambyse Rouzé

We study numerically the thermalisation and temporal evolution of the reduced density matrix for a two-site subsystem of a fermionic Hubbard model prepared far from equilibrium at a definite energy. Even for very small systems near quantum…

Quantum Physics · Physics 2011-01-24 S. Genway , A. F. Ho , D. K. K. Lee

We provide an overview of our numerical and analytical studies of isolated interacting quantum systems that are quenched out of equilibrium instantaneously. We describe the relaxation process to a new equilibrium and obtain lower bounds for…

Statistical Mechanics · Physics 2016-04-04 E. J. Torres-Herrera , Davida Kollmar , Lea F. Santos