Dynamics and interaction of vortex lines in an elongated Bose-Einstein condensate

TL;DR

This study investigates the real-time behavior of vortex lines in an elongated Bose-Einstein condensate, revealing their precession, interactions, and decay dynamics, with experimental results aligning well with theoretical models.

Contribution

It provides detailed experimental observations of vortex dynamics and interactions in elongated BECs, including vortex-vortex interactions and decay mechanisms, advancing understanding of quantum fluid behavior.

Findings

Vortices are spontaneously generated via the Kibble-Zurek mechanism.

Vortices precess with periods matching theoretical predictions.

Multiple vortices exhibit interaction signatures and faster decay.

Abstract

We study the real-time dynamics of vortex lines in a large elongated Bose-Einstein condensate (BEC) of sodium atoms using a stroboscopic technique. Vortices are spontaneously produced via the Kibble-Zurek mechanism in a quench across the BEC transition and then they slowly precess keeping their orientation perpendicular to the long axis of the trap as expected for solitonic vortices in a highly anisotropic condensate. Good agreement with theoretical predictions is found for the precession period as a function of the orbit amplitude and the number of condensed atoms. In configurations with two or more vortex lines, we see signatures of vortex-vortex interaction in the shape and visibility of the orbits. In addition, when more than two vortices are present, their decay is faster than the thermal decay observed for one or two vortices. The possible role of vortex reconnection processes is discussed.