Critical temperature of interacting Bose gases in periodic potentials.
The superfluid transition of a repulsive Bose gas in the presence of a sinusoidal potential which represents a simple-cubic optical lattice is investigated using quantum Monte Carlo simulations. At the average filling of one particle per well the critical temperature has a nonmonotonic dependence on the interaction strength, with an initial sharp increase and a rapid suppression at strong interactions in the vicinity of the Mott transition. In an optical lattice the positive shift of the transition is strongly enhanced compared to the homogenous gas. By varying the lattice filling we find a crossover from a regime where the optical lattice has the dominant effect to a regime where interactions dominate and the presence of the lattice potential becomes almost irrelevant.
The Abdus Salam International Centre for Theoretical Physics, 34151 Trieste, Italy and SISSA-International School for Advanced Studies, 34136 Trieste, Italy.
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TT
Nguyen
Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland.
A J
AJ
Herrmann
Theoretische Physik, ETH Zurich, 8093 Zurich, Switzerland.
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M
Troyer
The Abdus Salam International Centre for Theoretical Physics, 34151 Trieste, Italy.
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Pilati