Quantum Fisher Information as a Measure of Symmetry Breaking in Quantum Many-Body Systems

Fuente: arXiv
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Autori principali: Yamashika, Shion, Endo, Shimpei, Tajima, Hiroyasu
Natura: Preprint
Pubblicazione: 2025
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author Yamashika, Shion
Endo, Shimpei
Tajima, Hiroyasu
author_facet Yamashika, Shion
Endo, Shimpei
Tajima, Hiroyasu
contents Symmetry breaking underlies diverse phenomena from phase transitions in condensed matter to fundamental interactions in gauge theories. Despite many proposed indicators, a general quantification of symmetry breaking that is faithful, computable, and valid in the thermodynamic limit has remained elusive. Here, within quantum resource theory, we propose the quantum Fisher information (QFI) as such a measure. We demonstrate its utility by computing QFI for paradigmatic models: in the BCS superconductor, the QFI counts the number of Cooper pairs; in the transverse-field XY spin chains, it captures topological phase transition that has no local order parameter; and in quantum quench dynamics, it allows us to exactly derive the microscopic origin and conditions of the quantum Mpemba effect in terms of excitation propagation, including in the thermodynamic limit--beyond the reach of previous analyses. Our results show that the QFI, which is a complete resource monotone in the resource theory of asymmetry that plays the role of entanglement entropy in entanglement theory, faithfully captures symmetry breaking in condensed-matter systems. These results highlight the QFI as a universal and physically meaningful diagnostic of symmetry breaking in both equilibrium and non-equilibrium quantum many-body systems.
format Preprint
id arxiv_https___arxiv_org_abs_2509_07468
institution arXiv
publishDate 2025
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spellingShingle Quantum Fisher Information as a Measure of Symmetry Breaking in Quantum Many-Body Systems
Yamashika, Shion
Endo, Shimpei
Tajima, Hiroyasu
Statistical Mechanics
Quantum Gases
Quantum Physics
Symmetry breaking underlies diverse phenomena from phase transitions in condensed matter to fundamental interactions in gauge theories. Despite many proposed indicators, a general quantification of symmetry breaking that is faithful, computable, and valid in the thermodynamic limit has remained elusive. Here, within quantum resource theory, we propose the quantum Fisher information (QFI) as such a measure. We demonstrate its utility by computing QFI for paradigmatic models: in the BCS superconductor, the QFI counts the number of Cooper pairs; in the transverse-field XY spin chains, it captures topological phase transition that has no local order parameter; and in quantum quench dynamics, it allows us to exactly derive the microscopic origin and conditions of the quantum Mpemba effect in terms of excitation propagation, including in the thermodynamic limit--beyond the reach of previous analyses. Our results show that the QFI, which is a complete resource monotone in the resource theory of asymmetry that plays the role of entanglement entropy in entanglement theory, faithfully captures symmetry breaking in condensed-matter systems. These results highlight the QFI as a universal and physically meaningful diagnostic of symmetry breaking in both equilibrium and non-equilibrium quantum many-body systems.
title Quantum Fisher Information as a Measure of Symmetry Breaking in Quantum Many-Body Systems
topic Statistical Mechanics
Quantum Gases
Quantum Physics
url https://arxiv.org/abs/2509.07468