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Related papers: Chaos and thermalization in small quantum systems

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In classical systems, chaos is clearly defined via the behavior of trajectories. In quantum systems with a classical analogue one finds that the transition from regular to chaotic dynamics is signified by a change in the spectral…

Statistical Mechanics · Physics 2026-03-24 Fotis I. Giasemis

We study the non-equiliribium dynamics of atom-molecule Bose gases in a double-well potential. In this system, the internal atom-molecule tunneling has significant influence on the dynamics. We investigate the periodicity of dynamics by…

Quantum Gases · Physics 2015-05-28 Atsushi Motohashi

Thermalization of isolated quantum systems has been studied intensively in recent years and significant progresses have been achieved. Here, we study thermalization of small quantum systems that interact with large chaotic environments…

Statistical Mechanics · Physics 2019-06-05 Jiaozi Wang , Wen-ge Wang , Jiao Wang

The eigenstate thermalization hypothesis (ETH) and the theory of linear response (LRT) are celebrated cornerstones of our understanding of the physics of many-body quantum systems out of equilibrium. While the ETH provides a generic…

Statistical Mechanics · Physics 2019-05-29 Jonas Richter , Jochen Gemmer , Robin Steinigeweg

Despite the unitary evolution of closed quantum systems, long-time expectation of local observables are well described by thermal ensembles, providing the foundation of quantum statistical mechanics. A promising route to understanding this…

Quantum Physics · Physics 2026-02-03 Yuke Zhang , Pengfei Zhang

We consider a quantum system A U B made up of degrees of freedom that can be partitioned into spatially disjoint regions A and B. When the full system is in a pure state in which regions A and B are entangled, the quantum mechanics of…

Statistical Mechanics · Physics 2014-11-27 Vedika Khemani , Anushya Chandran , Hyungwon Kim , S. L. Sondhi

A profound quest of statistical mechanics is the origin of irreversibility - the arrow of time. New stimulants have been provided, thanks to unprecedented degree of control reached in experiments with isolated quantum systems and rapid…

Quantum Physics · Physics 2016-06-28 Chushun Tian , Kun Yang , Jiao Wang

Boltzmann's ergodic hypothesis furnishes a possible explanation for the emergence of statistical mechanics in the framework of classical physics. In quantum mechanics, the Eigenstate Thermalization Hypothesis (ETH) is instead generally…

Statistical Mechanics · Physics 2019-04-08 Lorenzo Campos Venuti , Lawrence Liu

Exactly solvable models that exhibit quantum signatures of classical chaos are both rare as well as important - more so in view of the fact that the mechanisms for ergodic behavior and thermalization in isolated quantum systems and its…

Quantum Physics · Physics 2019-06-26 Shruti Dogra , Vaibhav Madhok , Arul Lakshminarayan

We derive the Eigenstate Thermalization Hypothesis (ETH) from a random matrix Hamiltonian by extending the model introduced by J. M. Deutsch [Phys. Rev. A 43, 2046 (1991)]. We approximate the coupling between a subsystem and a many-body…

Statistical Mechanics · Physics 2018-09-26 Charlie Nation , Diego Porras

One of the fundamental problems of quantum statistical physics is how an ideally isolated quantum system can ever reach thermal equilibrium behavior despite the unitary time evolution of quantum-mechanical systems. Here, we study, via…

Quantum Physics · Physics 2025-06-24 Marvin Lenk , Sayak Biswas , Anna Posazhennikova , Johann Kroha

In their seminal work, Fermi, Pasta, Ulam and Tsingou explored the connection between statistical mechanics and dynamical properties, such as chaos and ergodicity. Even today, seventy years later, the topic is not fully understood: while…

Statistical Mechanics · Physics 2026-04-01 Marco Baldovin , Marco Cattaneo , Dario Lucente , Paolo Muratore-Ginanneschi , Angelo Vulpiani

Equilibrium properties of many-body systems with a large number of degrees of freedom are generally expected to be described by statistical mechanics. Such expectations are closely tied to the observation of thermalization, as manifested…

Quantum Gases · Physics 2025-08-08 Yulong Qiao , Frank Großmann , Peter Schlagheck , Gabriel M. Lando

A quantum dynamical model of two interacting spins, with chaotic and regular components, is investigated using a finite two-particles symmetrized basis. Chaotic eigenstates give rise to an equilibrium occupation number distribution in close…

chao-dyn · Physics 2019-08-17 F. Borgonovi , I. Guarneri , F. M. Izrailev , G. Casati

The grand canonical ensemble lies at the core of quantum and classical statistical mechanics. A small system thermalizes to this ensemble while exchanging heat and particles with a bath. A quantum system may exchange quantities represented…

Quantum Physics · Physics 2016-07-25 Nicole Yunger Halpern , Philippe Faist , Jonathan Oppenheim , Andreas Winter

According to the eigenstate thermalization hypothesis (ETH), the eigenstate-to-eigenstate fluctuations of expectation values of local observables should decrease with increasing system size. In approaching the thermodynamic limit - the…

Statistical Mechanics · Physics 2021-04-14 Goran Nakerst , Masudul Haque

Eigenstate thermalization hypothesis (ETH) represents a breakthrough in many-body physics since it allows to link thermalization of physical observables with the applicability of random matrix theory (RMT). Recent years were also extremely…

Statistical Mechanics · Physics 2024-08-06 Maksymilian Kliczkowski , Rafał Świętek , Miroslav Hopjan , Lev Vidmar

In this paper, we investigate the distinctions between realistic quantum chaotic systems and random models from the perspective of observable properties, particularly focusing on the eigenstate thermalization hypothesis (ETH). Through…

Chaotic Dynamics · Physics 2025-04-11 Xiao Wang , Jiaozi Wang , Wen-ge Wang

The Eigenstate Thermalization Hypothesis (ETH) explains emergence of the thermodynamic equilibrium by assuming a particular structure of observable's matrix elements in the energy eigenbasis. Schematically, it postulates that off-diagonal…

Statistical Mechanics · Physics 2022-05-11 Jiaozi Wang , Mats H. Lamann , Jonas Richter , Robin Steinigeweg , Anatoly Dymarsky , Jochen Gemmer

Statistical mechanics is founded on the assumption that all accessible configurations of a system are equally likely. This requires dynamics that explore all states over time, known as ergodic dynamics. In isolated quantum systems, however,…