Solitonic vortices in Bose–Einstein condensates
1 INO-CNR BEC Center and Dipartimento di Fisica, Università di Trento, 38123 Povo, Italy
2 Kapitza Institute for Physical Problems RAS, Kosygina 2, 119334 Moscow, Russia
Received: 15 October 2014
Revised: 19 February 2015
Published online: 9 April 2015
We analyse, theoretically and experimentally, the nature of solitonic vortices (SV) in an elongated Bose-Einstein condensate. In the experiment, such defects are created via the Kibble-Zurek mechanism, when the temperature of a gas of sodium atoms is quenched across the BEC transition, and are imaged after a free expansion of the condensate. By using the Gross-Pitaevskii equation, we calculate the in-trap density and phase distributions characterizing a SV in the crossover from an elongated quasi-1D to a bulk 3D regime. The simulations show that the free expansion strongly amplifies the key features of a SV and produces a remarkable twist of the solitonic plane due to the quantized vorticity associated with the defect. Good agreement is found between simulations and experiments.
© EDP Sciences, Springer-Verlag, 2015