Expansion of Tonks-Girardeau Gases on a One-Dimensional Optical Lattice

摘要

We study the free expansion of Tonks-Girardeau gases on one-dimensional lattices after removing the confining potential. We find that for low initial densities the momentum distribution of the expanding gas rapidly approaches the one of noninteracting fermions. In the opposite limit, i.e, when the initial system is a pure Mott insulator with one particle per lattice site, the expansion leads to the emergence of quasi-condensates at finite momentum. These traveling quasi-condensates develop quasi-long range one-particle correlations similar to the ones shown to be universal in the equilibrium case.