Volume 82, Number 3, May 2008
Article Number 30003
Number of page(s) 6
Section General
Published online 17 April 2008
EPL, 82 (2008) 30003
DOI: 10.1209/0295-5075/82/30003

Canonical structure of dynamical fluctuations in mesoscopic nonequilibrium steady states

C. Maes1 and K. Netocný2

1  Instituut voor Theoretische Fysica, K.U. Leuven - Celestijnenlaan 200D, B-3001 Leuven, Belgium, EU
2  Institute of Physics AS CR - Na Slovance 2, CZ-18221 Prague, Czech Republic, EU

received 3 October 2007; accepted in final form 10 March 2008; published May 2008
published online 17 April 2008

We give the explicit structure of the functional governing the dynamical density and current fluctuations for a mesoscopic system in a nonequilibrium steady state. Its canonical form determines a generalised Onsager-Machlup theory. We assume that the system is described as a Markov jump process satisfying a local detailed balance condition such as typical for stochastic lattice gases and for chemical networks. We identify the entropy current and the traffic between the mesoscopic states as extra terms in the fluctuation functional with respect to the equilibrium dynamics. The density and current fluctuations are coupled in general, except close to equilibrium where their decoupling explains the validity of entropy production principles.

05.70.Ln - Nonequilibrium and irreversible thermodynamics.
05.40.-a - Fluctuation phenomena, random processes, noise, and Brownian motion.
05.20.-y - Classical statistical mechanics.

© EPLA 2008