2004/09/15 by P. Buonsante, V. Penna, A. Vezzani
Physics and Astronomy · #cond-mat.stat-mech
published as Laser Physics 15 (2), 361 (2005) · 7 pages, 1 figure
arxiv created 2004/09/15 · arxiv updated 2009/12/01
We report a multiple-site mean-field analysis of the zero-temperature phase diagram for ultracold bosons in realistic optical superlattices. The system of interacting bosons is described by a Bose-Hubbard model whose site-dependent parameters reflect the nontrivial periodicity of the optical superlattice. An analytic approach is formulated based on the analysis of the stability of a fixed-point of the map defined by the self-consistency condition inherent in the mean-field approximation. The experimentally relevant case of the period-2 one-dimensional superlattice is briefly discussed. In particular, it is shown that, for a special choice of the superlattice parameters, the half-filling insulator domain features an unusual loophole shape that the single-site mean-field approach fails to capture.