Thermodynamic Langevin Equations

Fuente: arXiv
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Autori principali: Porporato, Amilcare, Calabrese, Salvatore, Rondoni, Lamberto
Natura: Preprint
Pubblicazione: 2024
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author Porporato, Amilcare
Calabrese, Salvatore
Rondoni, Lamberto
author_facet Porporato, Amilcare
Calabrese, Salvatore
Rondoni, Lamberto
contents The physical significance of the stochastic processes associated to the generalized Gibbs ensembles is scrutinized here with special attention to the thermodynamic fluctuations of small systems. The contact with the environment produces an interaction entropy, which controls the distribution of fluctuations and allows writing the generalized Gibbs ensembles for macrostates in potential form. This naturally yields exact nonlinear thermodynamic Langevin equations (TLEs) for such variables, with drift expressed in terms of entropic forces. The analysis of the canonical ensemble for an ideal monoatomic gas and the related TLEs show that introducing currents leads to nonequilibrium heat transfer conditions with interesting bounds on entropy production but with no obvious thermodynamic limit. For a colloidal particle under constant force, the TLEs for macroscopic variables are different from those for the microscopic position, typically used in the so-called stochastic thermodynamics; while TLEs are consistent with the fundamental equation obtained from the Hamiltonian, stochastic thermodynamics requires isothermal conditions and entropy proportional to position.
format Preprint
id arxiv_https___arxiv_org_abs_2409_00811
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Thermodynamic Langevin Equations
Porporato, Amilcare
Calabrese, Salvatore
Rondoni, Lamberto
Statistical Mechanics
The physical significance of the stochastic processes associated to the generalized Gibbs ensembles is scrutinized here with special attention to the thermodynamic fluctuations of small systems. The contact with the environment produces an interaction entropy, which controls the distribution of fluctuations and allows writing the generalized Gibbs ensembles for macrostates in potential form. This naturally yields exact nonlinear thermodynamic Langevin equations (TLEs) for such variables, with drift expressed in terms of entropic forces. The analysis of the canonical ensemble for an ideal monoatomic gas and the related TLEs show that introducing currents leads to nonequilibrium heat transfer conditions with interesting bounds on entropy production but with no obvious thermodynamic limit. For a colloidal particle under constant force, the TLEs for macroscopic variables are different from those for the microscopic position, typically used in the so-called stochastic thermodynamics; while TLEs are consistent with the fundamental equation obtained from the Hamiltonian, stochastic thermodynamics requires isothermal conditions and entropy proportional to position.
title Thermodynamic Langevin Equations
topic Statistical Mechanics
url https://arxiv.org/abs/2409.00811