Our work on slow mass transport and statistical evolution of atomic gases is published at Phys. Rev. Lett.104.160403 (2010). In this work, we show the in situ atomic density profiles provide a viable tool for investigating dynamic processes and holds promise for studying dynamics in the quantum critical regime.
The density and entropy profiles of a trapped, finite-temperature gas can vary in different regimes. In the tunneling-dominated regime, the center of the cloud is a superfluid (SF); in the interaction-dominated regime, the cloud can show a Mott-insulating domain (MI) with unit occupation number. The above two figures show that across the superfluid-to-Mott insulator transition, both the density and entropy profiles change and correspondingly, mass transport and entropy transport will be induced. The gray shaded area marks an extended region near unit site occupation number where quantum critical transport can take place.