Vortex stabilization in Bose-Einstein condensate of alkali atom gas

TL;DR

This paper theoretically demonstrates that finite temperature effects and focused laser pinning can stabilize vortices in Bose-Einstein condensates of alkali gases, providing detailed properties and excitation spectra.

Contribution

It introduces a self-consistent mean-field approach showing vortex stabilization mechanisms in BECs, including temperature effects and laser pinning.

Findings

Vortices are stabilized by finite temperature effects.

Laser pinning can stabilize vortices at zero temperature.

Detailed profiles and spectra of stable vortices are provided.

Abstract

A quantized vortex in the Bose-Einstein condensation (BEC), which is known to be unstable intrinsically, is demonstrated theoretically to be stabilized by the finite temperature effect. The mean-field calculation of Popov approximation within the Bogoliubov theory is employed, giving rise to a self-consistent solution for BEC confined by a harmonic potential. Physical origin of this vortex stabilization is investigated. An equivalent effect is also proved to be induced by an additional pinning potential at the vortex center produced by a focused laser beam even at the lowest temperature. The self-consistent solutions give detailed properties of a stable vortex, such as the spatial profiles of the condensate and non-condensate, the particle current density around the core, the whole excitation spectrum, and their temperature dependences.