FM 2003-12; mp_arc nlin/CD 0007???
versione 0.1 21/11/2003, versione 0.3 18 june 2004

Author: Giovanni Gallavotti

Title: Entropy production in nonequilibrium stationary states: a point of view

Abstract: Entropy might be a not well defined concept if the system can undergo transformations involving stationary nonequilibria. It might be analogous to the heat content (once called ``caloric'') in transformations that are not isochoric (\ie which involve mechanical work): it could be just a quantity that can be transferred or created, like heat in equilibrium. The text first reviews the philosophy behind a recently proposed definition of entropy production in nonequilibrium stationary systems. A detailed technical attempt at defining the entropy of a stationary states via their variational properties follows: the unsatisfactory aspects of the results add arguments in favor of the nonexistence of a function of state to be identified with entropy; at the same time new aspects and properties of the phase space contraction emerge.

Key words:  Nonequilibrium Thermodynamics, Entropy, Temperature pacs 47.52, 05.45, 47.70, 05.70.L, 05.20, 03.20
APS-PACS:  47.52.+j, 05.45.+b, 05.70.Ln, 47.70.-n

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