2004/11/30 by K. V. Krutitsky, M. Timmer, R. Graham
Physics and Astronomy · #cond-mat.other
paper · pdf · doi:10.1103/physreva.71.033623
published as Phys.Rev.A 71, 033623 (2005)
arxiv created 2005/03/29 · arxiv updated 2009/12/01
We investigate the superfluid--Mott-insulator quantum phase transition of spin-1 bosons in an optical lattice created by pairs of counterpropagating linearly polarized laser beams, driving an Fg=1 to Fe=1 internal atomic transition. The whole parameter space of the resulting two-component Bose-Hubbard model is studied. We find that the phase transition is not always second order as in the case of spinless bosons, but can be first order in certain regions of the parameter space. The calculations are done in the mean-field approximation by means of exact numerical diagonalization as well as within the framework of perturbaton theory.