Non-classicality at equilibrium and efficient predictions under non-commuting charges

• URL: http://arxiv.org/abs/2507.22882v1
• Date: Wed, 30 Jul 2025 17:57:06 GMT
• Title: Non-classicality at equilibrium and efficient predictions under non-commuting charges
• Abstract summary: A quantum thermodynamic system can conserve non-commuting observables, but the consequences of this phenomenon on relaxation are not fully understood.<n>We investigate this problem by leveraging an observable-dependent approach to equilibration and thermalization in isolated quantum systems.<n>Our work thus uncovers a novel connection between the relaxation of observables under non-commuting charges, weak values, and Kirkwood-Dirac quasiprobability distributions.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: A quantum thermodynamic system can conserve non-commuting observables, but the consequences of this phenomenon on relaxation are still not fully understood. We investigate this problem by leveraging an observable-dependent approach to equilibration and thermalization in isolated quantum systems. We extend such approach to scenarios with non-commuting charges, and show that it can accurately estimate the equilibrium distribution of coarse observables without access to the energy eigenvalues and eigenvectors. Our predictions do not require weak coupling and are not restricted to local observables, thus providing an advantage over the non-Abelian thermal state. Within this approach, weak values and quasiprobability distributions emerge naturally and play a crucial role in characterizing the equilibrium distributions of observables. We show and numerically confirm that, due to charges' non-commutativity, these weak values can be anomalous even at equilibrium, which has been proven to be a proxy for non-classicality. Our work thus uncovers a novel connection between the relaxation of observables under non-commuting charges, weak values, and Kirkwood-Dirac quasiprobability distributions.

Related papers

• When Isolated Quantum Systems Appear Classical [35.18016233072556]
  We show that classical behavior may emerge even when substantial coherence remains present in the equilibrium state.<n>This establishes a direct connection between two foundational questions: the origin of thermalization in isolated quantum systems and the quantum-to-classical transition.
  arXiv  Detail & Related papers  (2026-06-17T15:30:00Z)
• Uncertainty Relation for a Single Observable [0.0]
  We show that the uncertainty of a single observable already has a nontrivial lower bound originating from the noncommutativity between the observable and the quantum state.<n>We prove sharp lower bounds on the variance of a single observable and then sharpen them further by introducing the classical uncertainty of the observable under a fixed state.
  arXiv  Detail & Related papers  (2026-05-25T21:07:54Z)
• Fluctuations and Irreversibility: Historical and Modern Perspectives [23.10276706709171]
  This article traces the development of fluctuation theory and its deep connection to irreversibility.<n>We highlight recent advances by linking quantum fluctuation theorems with linear response theory.<n>Understanding quantum fluctuations is essential for clarifying the foundations of irreversibility.
  arXiv  Detail & Related papers  (2025-12-26T12:15:30Z)
• Freeness Reined in by a Single Qubit [36.94429692322632]
  We find that, even in this setting, the correlation functions predicted by free probability theory receive corrections of order $O(1)$.<n>We trace their origin to non-uniformly distributed stationary quantum states, which we characterize analytically and confirm numerically.
  arXiv  Detail & Related papers  (2025-12-15T19:00:09Z)
• Quasiprobability Thermodynamic Uncertainty Relation [0.0]
  We derive a quantum extension of the thermodynamic uncertainty relation where dynamical fluctuations are quantified by the Terletsky-Margenau-Hill quasiprobability.<n>The obtained inequality plays a complementary role to existing quantum thermodynamic uncertainty relations.
  arXiv  Detail & Related papers  (2025-08-20T01:51:03Z)
• False signatures of non-ergodic behavior in disordered quantum many-body systems [0.0]
  Ergodic isolated quantum many-body systems satisfy the eigenstate thermalization hypothesis (ETH)<n>The ETH does not specify what happens to expectation values of local observables within an energy window when the average over disorder realizations is taken.<n>We show how to adjust the energy window when analyzing expectation values of local observables in disordered quantum many-body systems.
  arXiv  Detail & Related papers  (2025-07-22T13:19:32Z)
• Quantum tunneling and anti-tunneling across entropic barriers [44.99833362998488]
  We study the dynamics of a quantum particle in a constricted two-dimensional channel.<n>We analyze how the onset of quantum corrections impacts the (semi-intuitive) high-temperature behaviour, as temperature is lowered.
  arXiv  Detail & Related papers  (2025-05-06T19:55:55Z)
• Symmetries, Conservation Laws and Entanglement in Non-Hermitian Fermionic Lattices [37.69303106863453]
  Non-Hermitian quantum many-body systems feature steady-state entanglement transitions driven by unitary dynamics and dissipation.<n>We show that the steady state is obtained by filling single-particle right eigenstates with the largest imaginary part of the eigenvalue.<n>We illustrate these principles in the Hatano-Nelson model with periodic boundary conditions and the non-Hermitian Su-Schrieffer-Heeger model.
  arXiv  Detail & Related papers  (2025-04-11T14:06:05Z)
• Instability of steady-state mixed-state symmetry-protected topological order to strong-to-weak spontaneous symmetry breaking [14.693424479293737]
  We investigate whether open quantum systems hosting mixed-state symmetry-protected topological states as steady states retain this property under symmetric perturbations. We find that typical symmetric perturbations cause strong-to-weak spontaneous symmetry breaking at arbitrarily small perturbations, destabilize the steady-state mixed-state symmetry-protected topological order. We construct a quantum channel which replicates the essential physics of the Lindbladian and can be efficiently simulated using only Clifford gates, Pauli measurements, and feedback.
  arXiv  Detail & Related papers  (2024-10-16T18:00:00Z)
• Evolution of expected values in open quantum systems [41.94295877935867]
  We show that in some cases the power performed by the system can be considered as a quantum observable.<n>As an application, the pure dephasing process is reinterpreted from this perspective.
  arXiv  Detail & Related papers  (2024-02-29T06:47:28Z)
• Thermodynamic precision in the nonequilibrium exchange scenario [0.0]
  We investigate the use of entangled nonequilibrium steady states as end-points of thermodynamic cycles. We shed light on the role of the entanglement between the two qubits for precise work absorption.
  arXiv  Detail & Related papers  (2023-07-25T08:54:46Z)
• Non-equilibrium quantum probing through linear response [41.94295877935867]
  We study the system's response to unitary perturbations, as well as non-unitary perturbations, affecting the properties of the environment. We show that linear response, combined with a quantum probing approach, can effectively provide valuable quantitative information about the perturbation and characteristics of the environment.
  arXiv  Detail & Related papers  (2023-06-14T13:31:23Z)
• Asymmetry and tighter uncertainty relations for R\'enyi entropies via quantum-classical decompositions of resource measures [0.0]
  It is known that the variance and entropy of quantum observables decompose into intrinsically quantum and classical contributions. Here a general method of constructing quantum-classical decompositions of resources such as uncertainty is discussed.
  arXiv  Detail & Related papers  (2023-04-12T08:49:48Z)
• Stochastic entropy production: Fluctuation relation and irreversibility mitigation in non-unital quantum dynamics [0.0]
  We study the entropy production in open quantum systems whose time evolution is described by a class of non-unital quantum maps. In particular, we consider Kraus operators that can be related to a nonequilibrium potential. Results are applied to the thermalization of a qubitibility with non-Markovian transient.
  arXiv  Detail & Related papers  (2022-10-14T14:40:55Z)
• Non-Abelian symmetry can increase entanglement entropy [62.997667081978825]
  We quantify the effects of charges' noncommutation on Page curves. We show analytically and numerically that the noncommuting-charge case has more entanglement.
  arXiv  Detail & Related papers  (2022-09-28T18:00:00Z)
• Non-equilibrium stationary states of quantum non-Hermitian lattice models [68.8204255655161]
  We show how generic non-Hermitian tight-binding lattice models can be realized in an unconditional, quantum-mechanically consistent manner. We focus on the quantum steady states of such models for both fermionic and bosonic systems.
  arXiv  Detail & Related papers  (2021-03-02T18:56:44Z)
• Subdiffusive dynamics and critical quantum correlations in a disorder-free localized Kitaev honeycomb model out of equilibrium [0.0]
  Disorder-free localization has recently emerged as a mechanism for ergodicity breaking in homogeneous lattice gauge theories. In this work we show that this mechanism can lead to unconventional states of quantum matter as the absence of thermalization lifts constraints imposed by equilibrium statistical physics.
  arXiv  Detail & Related papers  (2020-12-10T15:39:17Z)
• Non-equilibrium non-Markovian steady-states in open quantum many-body systems: Persistent oscillations in Heisenberg quantum spin chains [68.8204255655161]
  We investigate the effect of a non-Markovian, structured reservoir on an open Heisenberg spin chain. We establish a coherent self-feedback mechanism as the reservoir couples frequency-dependent to the spin chain.
  arXiv  Detail & Related papers  (2020-06-05T09:16:28Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.