title: Slow mass transport and statistical evolution of an atomic gas across the superfluid-Mott-insulator transition.
abstract: We study transport dynamics of ultracold cesium atoms in a two-dimensional optical lattice across the superfluid-Mott-insulator transition based on in situ imaging. Inducing the phase transition with a lattice ramping routine expected to be locally adiabatic, we observe a global mass redistribution which requires a very long time to equilibrate, more than 100 times longer than the microscopic time scales for on-site interaction and tunneling. When the sample enters the Mott-insulator regime, mass transport significantly slows down. By employing fast recombination loss pulses to analyze the occupancy distribution, we observe similarly slow-evolving dynamics, and a lower effective temperature at the center of the sample.
authors.affiliation: The James Franck Institute and Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Chen-Lung
authors.initials: CL
authors.lastname: Hung
authors.forename: Xibo
authors.initials: X
authors.lastname: Zhang
authors.forename: Nathan
authors.initials: N
authors.lastname: Gemelke
authors.forename: Cheng
authors.initials: C
authors.lastname: Chin