Dynamically stable multiply quantized vortices in dilute Bose-Einstein condensates

TL;DR

This paper investigates conditions under which multiply quantized vortices in dilute Bose-Einstein condensates can be made dynamically stable, challenging the usual instability and splitting observed in such systems.

Contribution

It identifies specific trap geometries and interaction parameters that stabilize multiquantum vortices, providing new insights into vortex stability in BECs.

Findings

Regions of trap asymmetry and interaction strength stabilize vortices

Doubly quantized vortices can be stable in spherical traps

Stability depends on trap geometry and interaction parameters

Abstract

Multiquantum vortices in dilute atomic Bose-Einstein condensates confined in long cigar-shaped traps are known to be both energetically and dynamically unstable. They tend to split into single-quantum vortices even in the ultralow temperature limit with vanishingly weak dissipation, which has also been confirmed in the recent experiments [Y. Shin et al., Phys. Rev. Lett. 93, 160406 (2004)] utilizing the so-called topological phase engineering method to create multiquantum vortices. We study the stability properties of multiquantum vortices in different trap geometries by solving the Bogoliubov excitation spectra for such states. We find that there are regions in the trap asymmetry and condensate interaction strength plane in which the splitting instability of multiquantum vortices is suppressed, and hence they are dynamically stable. For example, the doubly quantized vortex can be made dynamically stable even in spherical traps within a wide range of interaction strength values. We expect that this suppression of vortex-splitting instability can be experimentally verified.