Phase Transitions in Optical Lattices at Finite Temperatures |
| T.P. Polak a and T.K. Kopeć b
a Faculty of Physics, Adam Mickiewicz University of Poznań, Umultowska 85, 61-614 Poznań, Poland b Institute for Low Temperatures and Structure Research, Polish Academy of Sciences, Wrocław, Poland |
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| We discuss the finite-temperature phase diagram in three-dimensional Bose-Hubbard model relevant for the Bose-Einstein condensates in optical lattices, by employing U(1) quantum rotor approach and the topologically constrained path integral, that includes a summation over U(1) topological charge. The effective action formalism allows us to formulate a problem in the phase only action and obtain analytical formulae for the critical lines beyond mean-field theory. |
| DOI: 10.12693/APhysPolA.115.418 PACS numbers: 05.30.Jp, 03.75.Lm, 03.75.Nt, 67.40.Kh |