 
Summary: Journal of Statistical Physics, Vol. 127, No. 1, April 2007 ( C 2007 )
DOI: 10.1007/s1095500692335
Fluctuation Theorem for Currents and Schnakenberg
Network Theory
David Andrieux1 and Pierre Gaspard1
Received November 4, 2005; accepted October 9, 2006
Published Online: February 23, 2007
A fluctuation theorem is proved for the macroscopic currents of a system in a nonequilib
rium steady state, by using Schnakenberg network theory. The theorem can be applied,
in particular, in reaction systems where the affinities or thermodynamic forces are de
fined globally in terms of the cycles of the graph associated with the stochastic process
describing the time evolution.
KEY WORDS: nonequilibrium steady state, entropy production, affinities, thermody
namic forces, fluctuation theorem
1. INTRODUCTION
Outofequilibrium systems are ubiquitous in Nature and they play an essential role
in many physical, chemical and biological phenomena.(112)
In an isolated system,
a nonequilibrium state will spontaneously relax toward the state of thermodynamic
equilibrium. However, a nonequilibrium steady state can be maintained in open
