Scientific Computing Laboratory seminar will be held on Thursday, 25 August 2016 at 14:00 in the library reading room “Dr. Dragan Popović" of the Institute of Physics Belgrade. The talk entitled

"Improving mean-field theory for bosons in optical lattices via degenerate perturbation theory"

will be given by Martin Kuebler (Department of Physics, Technical University of Kaiserslautern, Germany).

The abstract of the talk:

Bosons in an optical lattice yield a paradigmatic quantum phase transition between a Mott insulator and a superfluid. Recently, a mean-field theory for the underlying Bose-Hubbard model has been developed, which allows to determine the location of this quantum phase transition quite accurately [1-3]. Here we extend the validity range of this mean-field theory with the help of a degenerate perturbation theory. This allows to study also harmonically confined optical lattices, where a wedding cake structure of insulating Mott shells with superfluid regions between the Mott shells emerges [4].

References:
[1] F. E. A. dos Santos and A. Pelster, Phys. Rev. A 79, 013614 (2009).
[2] B. Bradlyn, F. E. A. dos Santos, and A. Pelster, Phys. Rev. A 79, 013615 (2009).
[3] T. Wang, X.-F. Zhang, S. Eggert, and A. Pelster, Phys. Rev. A 87, 063615 (2013).
[4] K. Mitra, C. J. Williams, and C. A. R. Sa de Melo, Phys. Rev. A 77, 033607 (2008).