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Related papers: Quantum thermalization and average entropy of a su…

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Thermalization of isolated many-body systems is demonstrated by generalizing an approach originally due to von Neumann: For arbitrary initial states with a macroscopically well-defined energy, quantum mechanical expectation values become…

Statistical Mechanics · Physics 2015-07-02 Peter Reimann

Conventional wisdom holds that the von Neumann entropy corresponds to thermodynamic entropy, but Hemmo and Shenker (2006) have recently argued against this view by attacking von Neumann (1955) and his argument. I argue that Hemmo and…

History and Philosophy of Physics · Physics 2023-03-28 Eugene Y. S. Chua

Entropy is a fundamental concept in equilibrium statistical mechanics, yet its origin in the non-equilibrium dynamics of isolated quantum systems is not fully understood. A strong consensus is emerging around the idea that the stationary…

Statistical Mechanics · Physics 2017-09-20 Vincenzo Alba , Pasquale Calabrese

We introduce a data-driven diagnostic that combines the singular value decomposition (SVD) with an information-theoretic entropy to quantify the phase-space complexity of perturbed distribution functions in gyrokinetic turbulence. Applying…

Plasma Physics · Physics 2026-02-03 Go Yatomi , Motoki Nakata

We recently showed [Phys. Rev. Lett. 121, 220602 (2018)] that the average bipartite entanglement entropy of all energy eigenstates of the quantum Ising chain exhibits a universal (for translationally invariant quadratic fermionic models)…

Statistical Mechanics · Physics 2019-02-14 Lucas Hackl , Lev Vidmar , Marcos Rigol , Eugenio Bianchi

Simulations are performed of a small quantum system interacting with a quantum environment. The system consists of various initial states of two harmonic oscillators coupled to give normal modes. The environment is "designed" by its level…

Statistical Mechanics · Physics 2015-06-15 George L. Barnes , Michael E. Kellman

We treat the disordered Heisenberg model in 1D as the standard model of many-body localization (MBL). Two new and independent order parameters stemming solely from the half-chain von Neumann entanglement entropy $S_{\textrm{vN}}$ are…

Disordered Systems and Neural Networks · Physics 2025-12-04 Jie Chen , Chun Chen , Xiaoqun Wang

We describe a numerical algorithm for approximating the equilibrium-reduced density matrix and the effective (mean force) Hamiltonian for a set of system spins coupled strongly to a set of bath spins when the total system (system+bath) is…

Quantum Physics · Physics 2023-01-25 Tyler Chen , Yu-Chen Cheng

It has been suggested heuristically by Unruh and Wald, and independently by Page, that among systems with given energy and volume, thermal radiation has the largest entropy. The suggestion leads to the corresponding universal bound on…

High Energy Physics - Theory · Physics 2008-11-26 Itzhak Fouxon

We study an entropy measure for quantum systems that generalizes the von Neumann entropy as well as its classical counterpart, the Gibbs or Shannon entropy. The entropy measure is based on hypothesis testing and has an elegant formulation…

Quantum Physics · Physics 2014-02-19 F. Dupuis , L. Kraemer , P. Faist , J. M. Renes , R. Renner

We study the effect that the SU(2) symmetry, and the rich Hilbert space structure that it generates in lattice spin systems, has on the average entanglement entropy of highly excited eigenstates of local Hamiltonians and of random pure…

Quantum Physics · Physics 2023-12-04 Rohit Patil , Lucas Hackl , George R. Fagan , Marcos Rigol

The illustrative wave function for a quantum disentangled liquid (QDL) composed of light and heavy particles is examined within numerical simulations. Initial measurement on light particles gives rise to the volume law of the entanglement…

Statistical Mechanics · Physics 2023-02-23 E. Abbasgholinejad , S. Raeisi , A. Langari

Entanglement is considered a fundamental ingredient for quantum technologies and condensed matter systems are among the good candidates for quantum devices. For bipartite pure states the von Neumann entropy is a proper measure of…

Quantum Physics · Physics 2023-03-15 T. Pauletti , M. Garcia , G. A. Canella , V. V. França

We investigate quantum dynamical systems defined on a finite dimensional Hilbert space and subjected to an interaction with an environment. The rate of decoherence of initially pure states, measured by the increase of their von Neumann…

Quantum Physics · Physics 2009-11-10 Robert Alicki , Artur Lozinski , Prot Pakonski , Karol Zyczkowski

The change of the von Neumann entropy of a set of harmonic oscillators initially in thermal equilibrium and interacting linearly with an externally driven quantum system is computed by adapting the Feynman-Vernon influence functional…

Statistical Mechanics · Physics 2018-04-04 Erik Aurell , Ralf Eichhorn

Information on level density for nuclei with mass numbers A = 20 - 250 is deduced from discrete low-lying levels and neutron resonance data. The odd-mass nuclei exhibit in general 4 - 7 times the level density found for its neighboring…

Nuclear Experiment · Physics 2009-10-31 M. Guttormsen , M. Hjorth-Jensen , E. Melby , J. Rekstad , A. Schiller , S. Siem

We consider a generic system composed of a fixed number of particles distributed over a finite number of energy levels. We make only general assumptions about system's properties and the entropy. System's constraints other than fixed number…

Probability · Mathematics 2020-03-12 Tomasz M. Łapiński

In this Thesis, several results in quantum information theory are collected, most of which use entropy as the main mathematical tool. *While a direct generalization of the Shannon entropy to density matrices, the von Neumann entropy behaves…

Quantum Physics · Physics 2018-10-25 Christian Majenz

We present a simple strategy in order to show the existence and uniqueness of the infinite volume limit of thermodynamic quantities, for a large class of mean field disordered models, as for example the Sherrington-Kirkpatrick model, and…

Disordered Systems and Neural Networks · Physics 2009-11-07 Francesco Guerra , Fabio L. Toninelli

The mathematical structure of quantum entanglement is studied and classified from the point of view of quantum compound states. We show that t he classical-quantum correspondences such as encodings can be treated as dia gonal (d-)…

Quantum Physics · Physics 2007-05-23 Viacheslav P Belavkin , Masanori Ohya