Hydrodynamic spectrum of a superfluid in an elongated trap
Résumé
–In this article we study the hydrodynamic spectrum of a superfluid confined in a cylindrical trap. We show that the dispersion relation ω(q) of the phonon branch scales like √ q at large q, leading to a vanishingly small superfluid critical velocity. In practice the critical velocity is set by the breakdown of the hydrodynamic approximation. For a broad class of superfluids, this entails a reduction of the critical velocity by a factor (ω ⊥ /µc) 1/3 with respect to the free-space prediction (here ω ⊥ is the trapping frequency and µc the chemical potential of the cloud).
Domaines
Gaz Quantiques [cond-mat.quant-gas]| Origine | Fichiers produits par l'(les) auteur(s) |
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