Continuous Creation of a Vortex in a Bose-Einstein Condensate with Hyperfine Spin F=2

TL;DR

This paper demonstrates a method to continuously create vortices in a Bose-Einstein condensate with hyperfine spin F=2 by adiabatically reversing the axial magnetic field, and shows the condensate remains confined during this process.

Contribution

It introduces a numerical approach to show that a vortex can be formed without losing atoms, even when reversing the magnetic field slowly, and analyzes the effect of an optical plug.

Findings

A vortex can be created by reversing the axial magnetic field adiabatically.

A significant fraction of the condensate remains confined during vortex formation.

The condensate stays within the F_z=2 manifold throughout the process.

Abstract

It is shown that a vortex can be continuously created in a Bose-Einstein condensate with hyperfine spin F=2 in a Ioffe-Pritchard trap by reversing the axial magnetic field adiabatically. It may be speculated that the condensate cannot be confined in the trap since the weak-field seeking state makes transitions to the neutral and the strong-field seeking states due to the degeneracy of these states along the vortex axis when the axial field vanishes. We have solved the Gross-Pitaevskii equation numerically with given external magnetic fields to show that this is not the case. It is shown that a considerable fraction of the condensate remains in the trap even when the axial field is reversed rather slowly. This scenario is also analysed in the presence of an optical plug along the vortex axis. Then the condensate remains within the $F_z=2$ manifold, with respect to the local magnetic field, throughout the formation of a vortex and hence the loss of atoms does not take place.