Heidelberg 2015 – scientific programme
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A: Fachverband Atomphysik
A 23: Ultra-cold atoms, ions and BEC IV (with Q)
A 23.5: Talk
Wednesday, March 25, 2015, 15:30–15:45, C/HSW
Vortices in a toroidal Bose-Einstein condensate with a rotating weak link — Aleksander Yakimenko1, •Yuriy Bidasyuk2,3, Michael Weyrauch2, Yevgeniy Kuriatnikov1, and Stanislav Vilchinskii1 — 1Department of Physics, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine — 2Physikalisch-Technische Bundesanstalt, Braunschweig, Germany — 3Bogoliubov Institute for Theoretical Physics, Kyiv, Ukraine
Recent series of experiments on atomic Bose-Einstein Condensates (BECs) in toroidal traps with a rotating weak link demonstrated possibilities to controllably generate and destroy persistent currents in such systems [K.C. Wright et. al. Phys. Rev. Lett. 110, 025302 (2013), S. Eckel et.al. Nature 506, 200 (2014)]. Motivated by these experiments, we investigate deterministic discontinuous jumps between quantized circulation states in a toroidal BEC. These phase slips are induced by vortex excitations created by a rotating weak link. We analyze influence of a localized condensate density depletion and atomic superflows, governed by the rotating barrier, on the energetic and dynamical stability of the vortices in the ring-shaped condensate. We simulate in a three-dimensional dissipative mean field model the dynamics of the condensate using parameters similar to the experimental conditions. We investigate in detail the vortex dynamics which leads to the observed phase slips and demonstrate the crucial role of moving vortex-antivortex dipoles in this process. Moreover, we consider the dynamics of the stirred condensate far beyond the experimentally explored region and reveal surprising manifestations of complex vortex dynamics.