Volume 114, Number 6, June 2016
|Number of page(s)||5|
|Published online||15 July 2016|
Hydrodynamic spectrum of a superfluid in an elongated trap
1 Laboratoire Kastler Brossel, ENS-PSL Research University, CNRS, UPMC, Collège de France - 24, rue Lhomond, 75005 Paris, France
2 Département de physique, École Polytechnique - 91128 Palaiseau cedex, France
3 Laboratoire de Physique Statistique, École Normale Supérieure, PSL Research University, Université Paris Diderot Sorbonne Paris-Cité, Sorbonne Universités UPMC Univ Paris 06, CNRS - 24 rue Lhomond, 75005 Paris, France
Received: 1 June 2016
Accepted: 29 June 2016
In this article we study the hydrodynamic spectrum of a superfluid confined in cylindrical trap. We show that the dispersion relation of the phonon branch scales like 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 with respect to the free-space prediction (here is the trapping frequency and the chemical potential of the cloud).
PACS: 03.75.Kk – Dynamic properties of condensates; collective and hydrodynamic excitations, superfluid flow / 03.75.Ss – Degenerate Fermi gases / 37.10.Gh – Atom traps and guides
© EPLA, 2016
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.