Scientific Results

Current-phase relation of a Bose-Einstein condensate flowing through a weak link

Year: 2010

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

Autors Affiliation: CNR-INFM BEC center and Dipartimento di Fisica, Università di Trento, I-38050 Povo, Italy;
Theoretical Division, Mail Stop B214, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA

Abstract: We study the current-phase relation of a Bose-Einstein condensate flowing through a repulsive square barrier by solving analytically the one-dimensional Gross-Pitaevskii equation. The barrier height and width fix the current-phase relation j (delta phi), which tends to j similar to cos(delta phi/2) for weak barriers and to the Josephson sinusoidal relation j similar to sin(delta phi) for strong barriers. Between these two limits, the current-phase relation depends on the barrier width. In particular, for wide-enough barriers, we observe two families of multivalued current-phase relations. Diagrams belonging to the first family, already known in the literature, can have two different positive values of the current at the same phase difference. The second family, new to our knowledge, can instead allow for three different positive currents still corresponding to the same phase difference. Finally, we show that the multivalued behavior arises from the competition between hydrodynamic and nonlinear-dispersive components of the flow, the latter due to the presence of a soliton inside the barrier region.

Journal/Review: PHYSICAL REVIEW A

Volume: 81 (3)      Pages from: 033613  to: 033613

More Information: 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.
DOI: 10.1103/PhysRevA.81.033613

Citations: 15
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