Effect of an impulsive force on vortices in a rotating Bose-Einstein condensate

TL;DR

This paper investigates how impulsive changes in interaction strength and trapping potential affect vortex dynamics in a rotating Bose-Einstein condensate, revealing nonstationary oscillations, vortex number variations, and vortex decay behavior.

Contribution

It provides a detailed analysis of vortex responses to sudden parameter changes in a BEC using the Gross-Pitaevskii equation, highlighting new vortex behavior phenomena.

Findings

Vortex number increases with interaction strength increase

Vortex number decreases with interaction strength decrease

Vortex core expands faster than condensate during free expansion

Abstract

The effects of a sudden increase and decrease of the interatomic interaction and harmonic-oscillator trapping potential on vortices in a quasi two-dimensional rotating Bose-Einstein condensate are investigated using the mean-field Gross-Pitaevskii equation. Upon increasing the strength of interaction suddenly the condensate enters a nonstationary oscillating phase which starts to develop more vortices. The opposite happens if the strength is reduced suddenly. Eventually, the number of vortices attains a final value at large times. Similarly, the number of vortices increases (decreases) upon a sudden reduction (augmentation) in the trapping potential. We also study the decay of vortices when the rotation of the condensate is suddenly stopped. Upon a free expansion of a rotating BEC with vortices the radius of the vortex core increases more rapidly than the radius of the condensate. This makes the counting and detection of multiple vortex easier after a free expansion.