Coarse graining empirical densities and currents in continuous-space steady states

We present the conceptual and technical background required to describe and understand the correlations and fluctuations of the empirical density and current of steady-state diffusion processes on all time scales—observables central to statistical mechanics and thermodynamics on the level of individ...

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Main Authors: Cai Dieball, Aljaž Godec
Format: Article
Language:English
Published: American Physical Society 2022-09-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.4.033243
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author Cai Dieball
Aljaž Godec
author_facet Cai Dieball
Aljaž Godec
author_sort Cai Dieball
collection DOAJ
description We present the conceptual and technical background required to describe and understand the correlations and fluctuations of the empirical density and current of steady-state diffusion processes on all time scales—observables central to statistical mechanics and thermodynamics on the level of individual trajectories. We focus on the important and nontrivial effect of a spatial coarse graining. Making use of a generalized time-reversal symmetry we provide deeper insight about the physical meaning of fluctuations of the coarse-grained empirical density and current, and explain why a systematic variation of the coarse-graining scale offers an efficient method to infer bounds on a system's dissipation. Moreover, we discuss emerging symmetries in the statistics of the empirical density and current, and the statistics in the central-limit regime. More broadly our work promotes the application of stochastic calculus as a powerful direct alternative to Feynman-Kac theory and path-integral methods.
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spelling doaj.art-6e70de1b4f154ef2a7d0e6fafd37e2ac2024-04-12T17:24:51ZengAmerican Physical SocietyPhysical Review Research2643-15642022-09-014303324310.1103/PhysRevResearch.4.033243Coarse graining empirical densities and currents in continuous-space steady statesCai DieballAljaž GodecWe present the conceptual and technical background required to describe and understand the correlations and fluctuations of the empirical density and current of steady-state diffusion processes on all time scales—observables central to statistical mechanics and thermodynamics on the level of individual trajectories. We focus on the important and nontrivial effect of a spatial coarse graining. Making use of a generalized time-reversal symmetry we provide deeper insight about the physical meaning of fluctuations of the coarse-grained empirical density and current, and explain why a systematic variation of the coarse-graining scale offers an efficient method to infer bounds on a system's dissipation. Moreover, we discuss emerging symmetries in the statistics of the empirical density and current, and the statistics in the central-limit regime. More broadly our work promotes the application of stochastic calculus as a powerful direct alternative to Feynman-Kac theory and path-integral methods.http://doi.org/10.1103/PhysRevResearch.4.033243
spellingShingle Cai Dieball
Aljaž Godec
Coarse graining empirical densities and currents in continuous-space steady states
Physical Review Research
title Coarse graining empirical densities and currents in continuous-space steady states
title_full Coarse graining empirical densities and currents in continuous-space steady states
title_fullStr Coarse graining empirical densities and currents in continuous-space steady states
title_full_unstemmed Coarse graining empirical densities and currents in continuous-space steady states
title_short Coarse graining empirical densities and currents in continuous-space steady states
title_sort coarse graining empirical densities and currents in continuous space steady states
url http://doi.org/10.1103/PhysRevResearch.4.033243
work_keys_str_mv AT caidieball coarsegrainingempiricaldensitiesandcurrentsincontinuousspacesteadystates
AT aljazgodec coarsegrainingempiricaldensitiesandcurrentsincontinuousspacesteadystates