Vortex pump for Bose-Einstein condensates utilizing a time-averaged orbiting potential trap

TL;DR

This paper demonstrates a vortex pumping method for Bose-Einstein condensates using a magnetic time-averaged orbiting potential trap, avoiding additional radial optical confinement, and explores how to optimize vortex charge and stability.

Contribution

It introduces a vortex pump scheme that relies solely on magnetic confinement, with numerical simulations showing effective vortex generation and strategies to prevent vortex splitting and particle loss.

Findings

Multiple pumping cycles can produce highly charged vortices.

A weak optical plug reduces vortex splitting and particle loss.

The method is promising for experimental realization.

Abstract

We show that topological vortex pumping can be implemented for a dilute Bose-Einstein condensate confined in a magnetic time-averaged orbiting potential trap with axial optical confinement. Contrary to earlier proposals for the vortex pump, we do not employ an additional optical potential to trap the condensate in the radial direction, but instead, the radial confinement is provided by the magnetic field throughout the pumping cycle. By performing numerical simulations based on the spin-1 Gross-Pitaevskii equation, we find that several pumping cycles can be carried out to produce a highly charged vortex before a majority of the particles escape from the trap or before the vortex splits into singly charged vortices. On the other hand, we observe that an additional, relatively weak optical plug potential is efficient in preventing splitting and reducing particle loss. With these results, we hope to bring the vortex pump closer to experimental realization.