Approach to the nonequilibrium time-periodic state in a steady shear flow model

Abstract

The standard nonequilibrium molecular dynamics algorithm for steady shear flow (SLLOD ) employs Lees–Edwards periodic boundary conditions. It is not widely known that these boundary conditions make the system non–autonomous. The "steady state" shear stress is in fact time periodic. The standard sponse theory derivations for steady shear do not take proper account of these non–autonomous terms. In this paper we correct this deficiency. We show that these non–autonomous terms invalidate the Green-Kubo relation for the finite frequency shear viscosity of fluids under Lees-Edwards periodic boundary conditions. Show more