Finite-Temperature Renormalization Group Analysis of Interaction Effects   in 2D Lattices of Bose-Einstein Condensates
  By using a renormalization group analysis, we study the effect of interparticle interactions on the critical temperature at which the Berezinskii-Kosterlitz-Thouless (BKT) transition occurs for Bose-Einstein condensates loaded at finite temperature in a 2D optical lattice. We find that the critical temperature decreases as the interaction energy decreases; when U/J=36/\pi one has a vanishing critical temperature, signaling the possibility of a quantum phase transition of BKT type. 
A. Smerzi (1,2), P. Sodano (3), and A. Trombettoni (4) ((1) Istituto   Nazionale per la Fisica della Materia BEC-CRS and Dip...