Coupling vortex dynamics with collective excitations in Bose-Einstein Condensates

TL;DR

This paper investigates the collective excitations and expansion dynamics of a trapped Bose-Einstein condensate with a vortex line, introducing a variational method validated by numerical simulations to analyze observable modes.

Contribution

It presents a novel variational approach for analyzing vortex dynamics in Bose-Einstein condensates, aligning well with numerical solutions of the Gross-Pitaevskii equation.

Findings

Identification of four collective modes, with only three observable depending on trap anisotropy.

Validation of the variational method against numerical simulations.

Demonstration of excitation of collective modes via experimental modulation techniques.

Abstract

Here we analyze the collective excitations as well as the expansion of a trapped Bose-Einstein condensate with a vortex line at its center. To this end, we propose a variational method where the variational parameters have to be carefully chosen in order to produce reliable results. Our variational calculations agree with numerical simulations of the Gross-Pitaevskii equation. The system considered here turns out to exhibit four collective modes of which only three can be observed at a time depending of the trap anisotropy. We also demonstrate that these collective modes can be excited using well established experimental methods such as modulation of the s-wave scattering length.