Growth of spatial correlations during the aging of a simple structural glass

We investigate dynamical heterogenities in a binary Lennard-Jones system below the glass transition temperature, by computing spatial correlations of fluctuations in the aging regime. A theoretical framework based on the existence of a soft mode in the nonequilibrium dynamics predicts the presence of a dynamical correlation length which grows with time. In our simulations we find that correlations grow with growing waiting time, as expected from this picture.