Superfluid to normal fluid phase transition in the Bose gas trapped in\n two dimensional optical lattices at finite temperature

2015/05/07 by M. O. C. Pires, Pires, M. O. C., E. J. V. de Passos +1
Physics and Astronomy · #Atomic and Subatomic Physics Research #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #Quantum Gases (cond-mat.quant-gas) #Quantum, superfluid, helium dynamics

paper · pdf · doi:10.48550/arxiv.1505.01875

openalex publication_date 2015/05/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We develop the Hartree-Fock-Bogoliubov theory at finite temperature for Bose\ngas trapped in the two dimensional optical lattices. The on-site energy is\nconsidered low enough that the gas presents superfluid properties. We obtain\nthe condensate density as function of the temperature neglecting the anomalous\ndensity in the thermodynamics equations. The condensate fraction provide two\ncritical temperature. Below the temperature T_C1 there is one condensate\nfraction. Above two possible fractions merger up to the critical temperature\nT_C2. Then the gas provides an first order transition at temperature above\nT_C2 where the condensate fraction is null. We resume by a\nfinite-temperature phase diagram where can be identify three domains: the\nnormal fluid, the superfluid and the superfluid with two possible condensate\nfractions.\n

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