Signatures of a universal jump in the superfluid density in two-dimensional Bose gas with finite number of particles

Abstract

We study, within the classical fields approximation, a two-dimensional weakly interacting uniform Bose gas of a finite number of atoms. By using a grand canonical ensemble formalism we show that such systems exhibit, in addition to the Berezinskii-Kosterlitz-Thouless (BKT) and thermal phases, the intermediate region. This region is characterized by a decay of current-current correlations at low momenta and by an algebraic decay of the first-order correlations with an exponent being larger than the critical value predicted by the BKT theory. The density of the superfluid fraction at the temperature which separates the BKT phase from the intermediate region approaches the one found by Nelson and Kosterlitz for two-dimensional superfluids while the number of atoms is increased.

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Cited by in corpus (11)

• Observation of first and second sound in a BKT superfluid
• Quench dynamics of an ultracold two-dimensional Bose gas
• Josephson junction dynamics in a two-dimensional ultracold Bose gas
• Collective modes and superfluidity of a two-dimensional ultracold Bose gas
• Sound propagation in a two-dimensional Bose gas across the superfluid transition
• Phase transition dimensionality crossover from two to three dimensions in a trapped ultracold atomic Bose gas
• Berezinskii-Kosterlitz-Thouless phase induced by dissipating quasisolitons
• Periodic quenches across the Berezinskii-Kosterlitz-Thouless phase transition
• First and second sound in a dilute Bose gas across the BKT transition
• Mechanism for sound dissipation in a two-dimensional degenerate Fermi gas
• Simulating the Berezinskii-Kosterlitz-Thouless Transition with Complex Langevin