Non-equilibrium dynamics of a 1D Bose gas in a flat optical lattice potential

We study the dynamics of a bundle of expanding 1D Bose gases in a nearly flat 1D optical lattice potential in the intermediate coupling regime, which presents a challenge to theory. We observe the time-evolving spatial and quasimomentum distributions at a range of 1D atom densities and 1D lattice depths. Since it is difficult to exactly model these non-equilibrium dynamics, we take a first step towards theoretical understanding by comparing our measurements to the results of a Gutzwiller mean-field model.