Long-lived local quantum coherences from hydrodynamic large deviations

Fuente: arXiv
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Main Authors: McCulloch, Ewan, Jacoby, J. Alexander, Gopalakrishnan, Sarang
Format: Preprint
Published: 2026
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author McCulloch, Ewan
Jacoby, J. Alexander
Gopalakrishnan, Sarang
author_facet McCulloch, Ewan
Jacoby, J. Alexander
Gopalakrishnan, Sarang
contents We develop a framework to describe how quantum coherences between distinct charge sectors evolve under generic charge-conserving dynamics. Our framework captures the nonperturbative interactions between quantum coherences and hydrodynamic large deviations -- i.e., rare ``voids'' of low charge entropy. Conditional on surviving, the quantum coherence and its surrounding void form a collective polaron-like object. In one dimension, even at infinite temperature, we show that the lifetime of coherences is parametrically enhanced because they bind to voids. We use our framework to address two fundamental questions about generic quantum dynamics with a conserved charge. First, we argue that gapped Ruelle-Pollicott resonances are absent in the weak-noise limit, even in sectors of operator space that contain no hydrodynamic slow modes: instead, the spectral gap in all sectors vanishes nonperturbatively in the noise strength. Second, we compute the spacetime asymptotics of the dynamical single-particle Green's function, both in the weak-noise regime and in the absence of noise. In the noiseless case, we find that the void-coherence polaron undergoes subdiffusion, with an exponent we calculate. We support our general arguments with a microscopic derivation for random charge-conserving circuits, as well as numerical evidence from tensor-network simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2604_27074
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Long-lived local quantum coherences from hydrodynamic large deviations
McCulloch, Ewan
Jacoby, J. Alexander
Gopalakrishnan, Sarang
Quantum Physics
Statistical Mechanics
Strongly Correlated Electrons
High Energy Physics - Theory
We develop a framework to describe how quantum coherences between distinct charge sectors evolve under generic charge-conserving dynamics. Our framework captures the nonperturbative interactions between quantum coherences and hydrodynamic large deviations -- i.e., rare ``voids'' of low charge entropy. Conditional on surviving, the quantum coherence and its surrounding void form a collective polaron-like object. In one dimension, even at infinite temperature, we show that the lifetime of coherences is parametrically enhanced because they bind to voids. We use our framework to address two fundamental questions about generic quantum dynamics with a conserved charge. First, we argue that gapped Ruelle-Pollicott resonances are absent in the weak-noise limit, even in sectors of operator space that contain no hydrodynamic slow modes: instead, the spectral gap in all sectors vanishes nonperturbatively in the noise strength. Second, we compute the spacetime asymptotics of the dynamical single-particle Green's function, both in the weak-noise regime and in the absence of noise. In the noiseless case, we find that the void-coherence polaron undergoes subdiffusion, with an exponent we calculate. We support our general arguments with a microscopic derivation for random charge-conserving circuits, as well as numerical evidence from tensor-network simulations.
title Long-lived local quantum coherences from hydrodynamic large deviations
topic Quantum Physics
Statistical Mechanics
Strongly Correlated Electrons
High Energy Physics - Theory
url https://arxiv.org/abs/2604.27074