Instability and vortex ring dynamics in a three-dimensional superfluid flow through a constriction

Year: 2011

Authors: Piazza F., Collins LA., Smerzi A.

Autors Affiliation: INO-CNR, BEC Center, Via Sommarive 14, 38123 Povo, Trento, Italy;
Dipartimento di Fisica, Universita’ di Trento, 38123 Povo, Italy;
Theoretical Division, Mail Stop B214, Los Alamos National Laboratory, Los Alamos, NM 87545, USA

Abstract: We study the instability of a superfluid flow through a constriction in three spatial dimensions. We consider a Bose-Einstein condensate at zero temperature in two different geometries: a straight waveguide and a torus. The constriction consists of a broad, repulsive penetrable barrier. In the hydrodynamic regime, we find that the flow becomes unstable as soon as the velocity at the classical (Thomas-Fermi) surface equals the sound speed inside the constriction. At this critical point, vortex rings enter the bulk region of the cloud. The nucleation and dynamics scenario is strongly affected by the presence of asymmetries in the velocity and density of the background condensate flow.

Journal/Review: NEW JOURNAL OF PHYSICS

Volume: 13      Pages from: 43008-1  to: 43008-14

More Information: We acknowledge many helpful discussions with L P Pitaevskii. We especially thank Chris Ticknor for bringing to our attention the plaquette technique and providing us with subroutines for implementing it in our analysis programs. The Los Alamos National Laboratory is operated by Los Alamos National Security, LLC for the National Nuclear Security Administration of the US Department of Energy under contract no. DE-AC52-06NA25396.
KeyWords: Einstein Condensed Gas; Bose Condensate; Solitary Waves; Motions; Dissipation; Stability
DOI: 10.1088/1367-2630/13/4/043008

Citations: 23
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