Solitonic Vortices in Bose-Einstein Condensates

TL;DR

This paper investigates solitonic vortices in elongated Bose-Einstein condensates through combined theoretical modeling and experimental creation, revealing how free expansion amplifies their features and confirms their properties.

Contribution

It provides a comprehensive analysis of solitonic vortices in BECs, combining experimental creation via the Kibble-Zurek mechanism with Gross-Pitaevskii simulations to understand their in-trap and expansion characteristics.

Findings

Free expansion amplifies SV features

Simulations match experimental observations

Twist of solitonic plane observed after expansion

Abstract

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 elongate 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.