Author: Giovanni Gallavotti

Title Irreversibility time scale: (version 1.1: 26 Mar 2006 )

Abstract: We introduce the entropy creation rate for a system interacting with thermostats ({\it i.e.}, in the usual language, for a subsystem subject to internal conservative forces interacting with the ``outside'' thermostats via conservative forces) and prove a fluctuation theorem for it. 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).

Key words:  Nonequilibrium Themodynamics, Statistical mechanics, Chaos, Fluctuation Theorem, Entropy, Irreversibility, Thermostats

PACS:  47.52.+j, 05.45.-a, 05.70.Ln, 05.20.-y

Giovanni Gallavotti
Fisica, Universita' di Roma 1
P.le Moro 2
00185 Roma, Italia
tel +39-06-4991-4370
fax +39-06-4957697

em: giovanni.gallavotti@roma1.infn.it
http://ipparco.roma1.infn.it