Mott insulators in an optical lattice with high filling factors

D. van Oosten, P. van der Straten, H. T. C. Stoof

Published 2002-05-03, updated 2002-10-25Version 2

We discuss the superfluid to Mott insulator transition of an atomic Bose gas in an optical lattice with high filling factors. We show that also in this multi-band situation, the long-wavelength physics is described by a single-band Bose-Hubbard model. We determine the many-body renormalization of the tunneling and interaction parameters in the effective Bose-Hubbard Hamiltonian, and consider the resulting model at nonzero temperatures. We show that in particular for a one or two-dimensional optical lattice, the Mott insulator phase is more difficult to realize than anticipated previously.