Irreversibility time scale

TL;DR

This paper introduces an entropy creation rate for systems with thermostats, proves a fluctuation theorem, and defines an irreversibility time scale to quantify when irreversibility appears in nonequilibrium processes, with applications to classical examples.

Contribution

It presents a novel entropy creation rate, establishes a fluctuation theorem for it, and defines an irreversibility time scale with practical evaluations in classical processes.

Findings

Fluctuation theorem for entropy creation rate established

Irreversibility time scale quantified in classical processes

Application to Joule-Thompson gas expansion

Abstract

Entropy creation rate is introduced for a system interacting with thermostats ({\it i.e.}, in the usual language, for a system subject to internal conservative forces interacting with ``external'' thermostats via conservative forces) and a fluctuation theorem for it is proved. As an application a time scale is introduced, to be interpreted as the time over which irreversibility becomes manifest in a process leading from an initial to a final stationary state of a mechanical system in a general nonequilibrium context. The time scale is evaluated in a few examples, including the classical Joule-Thompson process (gas expansion in a vacuum). The new version (n.2) contains several comments on references pointed out to me after posting the version n.1.