Hybridization of first and second sound in a weakly interacting Bose gas

Year: 2015

Authors: AU Verney L., Pitaevskii L., Stringari S.

Autors Affiliation: Ecole Normale Super, Int Ctr Fundamental Phys, F-75231 Paris, France; Univ Trento, INO CNR BEC Ctr, I-38123 Povo, Italy; Univ Trento, Dipartimento Fis, I-38123 Povo, Italy; PL Kapitsa Phys Problems Inst, Moscow 119334, Russia

Abstract: Using Landau’s theory of two-fluid hydrodynamics we investigate the sound modes propagating in a uniform weakly interacting superfluid Bose gas for values of temperature up to the critical point. In order to evaluate the relevant thermodynamic functions needed to solve the hydrodynamic equations, including the temperature dependence of the superfluid density, we use the Bogoliubov theory at low temperatures and the results of a perturbative approach based on the Beliaev diagrammatic technique at higher temperatures. Special focus is given on the hybridization phenomenon between first and second sound which occurs at low temperatures of the order of the interaction energy and we discuss explicitly the behavior of the two sound velocities near the hybridization point. Copyright (C) EPLA, 2015

Journal/Review: EPL

Volume: 111 (4)      Pages from: 40005-1  to: 40005-5

DOI: 10.1209/0295-5075/111/40005

Citations: 15
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