Tagged particle diffusion in 3d lattice gas cellular automata

Abstract

We report simulations of tagged particle diffusion in three-dimensional lattice gas cellular automata (LGCA). In particular we looked at the decay of the velocity autocorrelation function (VACF) using a new technique that is about a million times more efficient than the conventional techniques. For longer times the simulations clearly show the algebraic t 3/2 tail of the VACF. We compare the observed long-time tail with the predictions of mode-coupling theory. In three dimensions, the amplitude of this tail is found to agree within the (small) statistical error with these predictions.