Work statistics of sudden Quantum quenches: A random matrix theory perspective on Gaussianity and its deviations

Fuente: arXiv
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Main Author: Tierz, Miguel
Format: Preprint
Published: 2025
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author Tierz, Miguel
author_facet Tierz, Miguel
contents We show that, for sudden quenches, the work distribution reduces to the statistics of traces of powers of Haar unitaries, which are random unitary matrices drawn uniformly from the unitary group. For translation-invariant quadratic fermionic chains with interactions extending to $m$ neighbors and periodic boundary conditions, the Loschmidt amplitude admits a unitary matrix-model / Toeplitz representation, which yields a work variable of the form $W=\sum_{r\le m} a_r\,\mathrm{Re}\,\mathrm{Tr}\,U^r$ (and in models with pairing terms -- superconducting pairing -- additional $b_r\,\mathrm{Im}\,\mathrm{Tr}\,U^r$ terms appear). By invoking multivariate central limit theorems for vectors of traces of unitaries, we obtain a Gaussian distribution for $P(W)$ with variance $\mathrm{Var}(W)=\frac{1}{2}\sum_r r\,(a_r^2+b_r^2)$ and asymptotic independence across different powers. We also characterise the conditions under which non-Gaussian tails arise, for example from many interaction terms or their slow decay, as well as the appearance of Fisher--Hartwig singularities. We illustrate these mechanisms in the XY chain. Various numerical diagnostics support the analytical results.
format Preprint
id arxiv_https___arxiv_org_abs_2509_09640
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Work statistics of sudden Quantum quenches: A random matrix theory perspective on Gaussianity and its deviations
Tierz, Miguel
Quantum Physics
Statistical Mechanics
Strongly Correlated Electrons
Mathematical Physics
We show that, for sudden quenches, the work distribution reduces to the statistics of traces of powers of Haar unitaries, which are random unitary matrices drawn uniformly from the unitary group. For translation-invariant quadratic fermionic chains with interactions extending to $m$ neighbors and periodic boundary conditions, the Loschmidt amplitude admits a unitary matrix-model / Toeplitz representation, which yields a work variable of the form $W=\sum_{r\le m} a_r\,\mathrm{Re}\,\mathrm{Tr}\,U^r$ (and in models with pairing terms -- superconducting pairing -- additional $b_r\,\mathrm{Im}\,\mathrm{Tr}\,U^r$ terms appear). By invoking multivariate central limit theorems for vectors of traces of unitaries, we obtain a Gaussian distribution for $P(W)$ with variance $\mathrm{Var}(W)=\frac{1}{2}\sum_r r\,(a_r^2+b_r^2)$ and asymptotic independence across different powers. We also characterise the conditions under which non-Gaussian tails arise, for example from many interaction terms or their slow decay, as well as the appearance of Fisher--Hartwig singularities. We illustrate these mechanisms in the XY chain. Various numerical diagnostics support the analytical results.
title Work statistics of sudden Quantum quenches: A random matrix theory perspective on Gaussianity and its deviations
topic Quantum Physics
Statistical Mechanics
Strongly Correlated Electrons
Mathematical Physics
url https://arxiv.org/abs/2509.09640