Expansion of matter waves in static and driven periodic potentials

Abstract

We study the nonequilibrium dynamics of cold atoms held in an optical lattice subjected to a periodic driving potential. The expansion of an initially confined atom cloud occurs in two phases: an initial quadratic expansion followed by a ballistic behavior at long times. Accounting for this gives a good description of recent experimental results and provides a robust method to extract the effective intersite tunneling from time-of-flight measurements.