Coupled superfluidity of binary Bose mixtures in two dimensions

Year: 2019

Authors: Karle V., Defenu N., Enss T.

Autors Affiliation: Heidelberg Univ, Inst Theoret Phys, D-69120 Heidelberg, Germany; IST Austria, A-3400 Klosterneuburg, Austria.

Abstract: We consider a two-component Bose gas in two dimensions at a low temperature with short-range repulsive interaction. In the coexistence phase where both components are superfluid, interspecies interactions induce a nondissipative drag between the two superfluid flows (Andreev-Bashkin effect). We show that this behavior leads to a modification of the usual Berezinskii-Kosterlitz-Thouless (BKT) transition in two dimensions. We extend the renormalization of the superfluid densities at finite temperature using the renormalization-group approach and find that the vortices of one component have a large influence on the superfluid properties of the other, mediated by the nondissipative drag. The extended BKT flow equations indicate that the occurrence of the vortex unbinding transition in one of the components can induce the breakdown of superfluidity also in the other, leading to a locking phenomenon for the critical temperatures of the two gases.

Journal/Review: PHYSICAL REVIEW A

Volume: 99 (6)      Pages from: 63627-1  to: 63627-11

More Information: We acknowledge stimulating discussions with Thomas Gasenzer, Johannes Hofmann, Andrea Trombettoni, and, in particular, Gergely Zarand, who proposed the problem. This work was supported by Deutsche Forschungsgemeinschaft (DFG) via Collaborative Research Centre SFB 1225 (ISO-QUANT) and under Germany’s Excellence Strategy EXC-2181/1-390900948 (Heidelberg STRUCTURES Excellence Cluster).
KeyWords: Einstein Condensate; Phase-diagram; Vortices; Renormalization; Gases
DOI: 10.1103/PhysRevA.99.063627

Citations: 16
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