Lifetime of dynamic heterogeneities in a binary Lennard-Jones mixture

A four-time correlation function was calculated using a computer simulation of a binary Lennard-Jones mixture. The information content of the four-time correlation function is similar to that of four-time correlation functions measured in NMR experiments. The correlation function selects a sub-ensemble and analyzes its dynamics after some waiting time. The lifetime of the sub-ensemble selected by the four-time correlation function is calculated, and compared to the lifetimes of slow sub-ensembles selected using two different definitions of mobility, and to the $\alpha$ relaxation time.Comment: accepted for publication in Phys. Rev.