Phase transitions of a Bose gas in an optical lattice
arXiv:cond-mat/0303593
Abstract
A grand-canonical system of interacting bosons is considered to study phase transitions of ultracold atoms in an optical lattice. The phase diagram is discussed in terms of a matrix-like order parameter, representing a symmetric phase (Mott insulator) and a symmetry-broken phase (Bose-Einstein condensate). An exact solution was found by introducing $N$ colors and taking the limit $N\to\infty$.
12 pages, 4 figures, talk given at LPHYS '02