APPROACH TO THE NONEQUILIBRIUM TIME-PERIODIC STATE IN A STEADY SHEAR-FLOW MODEL

The standard non-equilibrium molecular dynamics algorithm for steady s hear flow (SLLOD) employs Lees-Edwards periodic boundary conditions. I t is not widely known that these boundary conditions make the system n on-autonomous. The 'steady state' shear stress is in fact time periodi c. The standard response theory derivations for steady shear do not ta ke proper account of these non-autonomous terms. In this paper we corr ect this deficiency. We show that these non-autonomous terms invalidat e the Green-Kubo relation for the finite frequency shear viscosity of fluids under Lees-Edwards periodic boundary conditions.