A local fluctuation theorem

The fluctuation theorem gives an analytic expression for the probability, i n a nonequilibrium system of finite size observed for a finite time, that t he dissipative flux will flow in the reverse direction to that required by the second law of thermodynamics. In the present paper a local version of t he fluctuation theorem (LFT) is derived heuristically. We find that in the case of planar Poiseuille flow of a Newtonian fluid between thermostated wa lls, nonequilibrium molecular dynamics simulation results support our propo sed LFT. (C) 2001 American Institute of Physics.