Nonequilibrium Fluctuation-Response Theory in the Frequency Domain

Fuente: arXiv
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Main Authors: Kwon, Euijoon, Chun, Hyun-Myung, Park, Hyunggyu, Lee, Jae Sung
Format: Preprint
Published: 2026
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author Kwon, Euijoon
Chun, Hyun-Myung
Park, Hyunggyu
Lee, Jae Sung
author_facet Kwon, Euijoon
Chun, Hyun-Myung
Park, Hyunggyu
Lee, Jae Sung
contents We develop a unified fluctuation-response theory in the frequency domain for nonequilibrium steady states governed by overdamped Langevin dynamics and Markov jump processes. The relation expresses the power spectrum of general observables exactly as a quadratic form of local responses measured at the same frequency, thereby extending static nonequilibrium fluctuation-response relations to finite frequencies. The decomposition is spatial for Langevin systems and edge-resolved for Markov jump processes, and applies uniformly to state-dependent observables, current-like observables, and their combinations. As consequences of the same identity, we derive frequency-domain response uncertainty relations, kinetic and thermodynamic uncertainty relations, the equilibrium fluctuation-dissipation theorem, and Harada-Sasa-type relations. Applications to stochastic networks and driven diffusive systems illustrate how the theory resolves fluctuation spectra into edge-wise contributions and reveals frequency-dependent tradeoffs between fluctuations, response, and dissipation.
format Preprint
id arxiv_https___arxiv_org_abs_2605_05038
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Nonequilibrium Fluctuation-Response Theory in the Frequency Domain
Kwon, Euijoon
Chun, Hyun-Myung
Park, Hyunggyu
Lee, Jae Sung
Statistical Mechanics
We develop a unified fluctuation-response theory in the frequency domain for nonequilibrium steady states governed by overdamped Langevin dynamics and Markov jump processes. The relation expresses the power spectrum of general observables exactly as a quadratic form of local responses measured at the same frequency, thereby extending static nonequilibrium fluctuation-response relations to finite frequencies. The decomposition is spatial for Langevin systems and edge-resolved for Markov jump processes, and applies uniformly to state-dependent observables, current-like observables, and their combinations. As consequences of the same identity, we derive frequency-domain response uncertainty relations, kinetic and thermodynamic uncertainty relations, the equilibrium fluctuation-dissipation theorem, and Harada-Sasa-type relations. Applications to stochastic networks and driven diffusive systems illustrate how the theory resolves fluctuation spectra into edge-wise contributions and reveals frequency-dependent tradeoffs between fluctuations, response, and dissipation.
title Nonequilibrium Fluctuation-Response Theory in the Frequency Domain
topic Statistical Mechanics
url https://arxiv.org/abs/2605.05038