Comment on “Modified nonequilibrium molecular dynamics for fluid flows with energy conservation” [J. Chem. Phys. 106 , 5615 (1997)]

Abstract

In their recent paper and the associated Response to this Comment, Tuckerman et al. dispute the form of the Liouville equation, as proposed by Liouville in 1838. They go on to introduce a definition of the entropy which is at variance with Boltzmann’s H-function and with Gibbs’ definition of entropy. They argue that their “entropy” is a constant of the motion, equal to its initial equilibrium value regardless of the imposition of external fields. We argue that the analysis of Tuckerman et al. is incorrect and that issues raised by Tuckerman et al. are not at all new but have already been correctly incorporated into nonequilibrium statistical mechanics.