Can the dynamics of an atomic glass-forming system be described as a continuous time random walk?

Abstract

We show that the dynamics of supercooled liquids, analyzed from computer simulations of the binary mixture Lennard-Jones system, can be described in terms of a continuous time random walk (CTRW). The required discretization comes from mapping the dynamics on transitions between metabasins. This comparison involves verifying the conditions of the CTRW as well as a quantitative test of the predictions. In particular it is possible to express the wave vector-dependence of the relaxation time as well as the degree of non-exponentiality in terms of the first three moments of the waiting time distribution.