Temporal ordering of nonequilibrium fluctuations as a corollary of the second law of thermodynamics

Abstract

In nonequilibrium steady states, the probabilities of the time-reversed paths differ in general from the path probabilities and they decrease at different rates given, respectively, by the time-reversed and standard entropies per unit time. These quantities characterize temporal disorder in the time-reversed paths and the paths themselves. The difference between these quantities gives the thermodynamic entropy production in units of Boltzmann's constant. Out of equilibrium, the temporal disorder of the time-reversed paths turns out to be larger than the temporal disorder of the paths themselves. In this way, a theorem is obtained according to which the temporal order of the paths is greater than for the time-reversed paths. The temporal disorder or dynamical randomness of the paths and their time-reversal have large-deviation properties directly connected to the thermodynamic entropy production. To cite this article: P. Gaspard, C. R. Physique 8 (2007).