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Related papers: Quantum thermalization and the route to ergodicity

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The eigenstate thermalization hypothesis (ETH) insists that for nonintegrable systems each energy eigenstate accurately gives microcanonical expectation values for a class of observables. As a mechanism for ETH to hold, we show that the…

Statistical Mechanics · Physics 2018-05-15 Takaaki Monnai

We study the validity of the eigenstate thermalization hypothesis (ETH) and its role for the occurrence of initial-state independent (ISI) equilibration in closed quantum many-body systems. Using the concept of dynamical typicality, we…

Quantum Physics · Physics 2015-06-19 Abdellah Khodja , Robin Steinigeweg , Jochen Gemmer

The Eigenstate Thermalization Hypothesis (ETH) provides a sufficient condition for thermalization of isolated quantum systems. While the standard ETH is formulated in the absence of degeneracy, physical systems often possess symmetries that…

High Energy Physics - Theory · Physics 2026-05-27 Soma Onoda , Osamu Fukushima , Ryusuke Hamazaki , Okuto Morikawa

Currently there are two main approaches to describe how quantum statistical physics emerges from an isolated quantum many-body system in a pure state: Canonical Typicality (CT) and Eigenstate Thermalization Hypothesis (ETH). These two…

Statistical Mechanics · Physics 2018-01-31 Anatoly Dymarsky , Hong Liu

We study aspects of chaos and thermodynamics at strong coupling in a scalar model using LCT numerical methods. We find that our eigenstate spectrum satisfies Wigner-Dyson statistics and that the coefficients describing eigenstates in our…

High Energy Physics - Theory · Physics 2023-02-22 Luca V. Delacretaz , A. Liam Fitzpatrick , Emanuel Katz , Matthew T. Walters

We study the Eigenstate Thermalization Hypothesis (ETH) in chaotic conformal field theories (CFTs) of arbitrary dimensions. Assuming local ETH, we compute the reduced density matrix of a ball-shaped subsystem of finite size in the infinite…

High Energy Physics - Theory · Physics 2018-06-14 Nima Lashkari , Anatoly Dymarsky , Hong Liu

We study thermalization in many-body quantum systems locally coupled to an external bath. It is shown that quantum chaotic systems do thermalize, that is, they exhibit relaxation to an invariant ergodic state which, in the bulk, is well…

Quantum Physics · Physics 2010-05-31 Marko Znidaric , Tomaz Prosen , Giuliano Benenti , Giulio Casati , Davide Rossini

Fading ergodicity provides a theoretical framework for understanding deviations from the eigenstate thermalization hypothesis (ETH) near ergodicity-breaking transitions. In this work, we demonstrate that the breakdown of the ETH at the…

Statistical Mechanics · Physics 2025-02-17 Rafał Świętek , Patrycja Łydżba , Lev Vidmar

Complexity of dynamics is at the core of quantum many-body chaos and exhibits a hierarchical feature: higher-order complexity implies more chaotic dynamics. Conventional ergodicity in thermalization processes is a manifestation of the…

Statistical Mechanics · Physics 2020-05-06 Kazuya Kaneko , Eiki Iyoda , Takahiro Sagawa

Eigenstate thermalization hypothesis (ETH) is discussed. We show that one common formulation of ETH does not necessarily imply thermalization of an observable of isolated many body quantum system. To get thermalization one has to postulate…

Statistical Mechanics · Physics 2020-02-06 Oleg Inozemcev , Igor Volovich

Understanding how out-of-equilibrium states thermalize under quantum unitary dynamics is an important problem in many-body physics. In this work, we propose a statistical ansatz for the matrix elements of non-equilibrium initial states in…

Statistical Mechanics · Physics 2025-04-30 Laura Foini , Anatoly Dymarsky , Silvia Pappalardi

We investigate the eigenstate thermalization hypothesis (ETH) in integrable models, focusing on the spin-1/2 isotropic Heisenberg (XXX) chain. We provide numerical evidence that ETH holds for typical eigenstates (weak ETH scenario).…

Strongly Correlated Electrons · Physics 2015-04-22 Vincenzo Alba

Having analytical instances of the Eigenstate Thermalization Hypothesis (ETH) is of obvious interest, both for fundamental and applied reasons. This is generically a hard task, due to the belief that non-linear interactions are basic…

Quantum Physics · Physics 2016-08-01 Javier M. Magan

Isolated quantum system in a pure state may be perceived as thermal if only substantially small fraction of all degrees of freedom is probed. We propose that in a chaotic quantum many-body system all states with sufficiently small energy…

Statistical Mechanics · Physics 2019-01-09 Anatoly Dymarsky , Hong Liu

It is commonly believed that quantum isolated systems satisfying the eigenstate thermalization hypothesis (ETH) are diffusive. We show that this assumption is too restrictive, since there are systems that are asymptotically in a thermal…

Statistical Mechanics · Physics 2016-10-25 David J. Luitz , Yevgeny Bar Lev

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

The Eigenstate Thermalization Hypothesis(ETH) is a standard tool to understand the thermalization properties of an isolated quantum system. Its generalization to higher order correlations of matrix elements of local operators, dubbed the…

Statistical Mechanics · Physics 2025-10-08 Tanay Pathak

Ergodicity has been one of the fundamental concepts underpinning our understanding of thermalization in isolated systems since the first developments in classical statistical mechanics. Recently, a similar notion has been introduced for…

Quantum Physics · Physics 2025-08-20 Leonard Logaric , John Goold , Shane Dooley

We use field-theoretic methods to explore the statistics of eigenfunctions of the Floquet operator for a large family of Floquet random quantum circuits. The correlation function of the quasienergy eigenstates is calculated and shown to…

Quantum Physics · Physics 2022-10-14 Yunxiang Liao , Victor Galitski

The Eigenstate Thermalization Hypothesis (ETH) was developed as a framework for understanding how the principles of statistical mechanics emerge in the long-time limit of isolated quantum many-body systems. Since then, ETH has shifted the…

Statistical Mechanics · Physics 2025-12-01 Elisa Vallini , Laura Foini , Silvia Pappalardi