Kelvin Waves of Quantized Vortex Lines in Trapped Bose-Einstein Condensates

TL;DR

This paper theoretically investigates Kelvin waves in vortex lines within trapped Bose-Einstein condensates, revealing instability mechanisms, decay processes, and proposing methods to excite specific Kelvin wave modes.

Contribution

It introduces a modified dispersion relation for Kelvin waves in trapped superfluids and a method to selectively excite Kelvin waves of desired wave numbers.

Findings

Counterrotating perturbation causes elliptical instability via parametric resonance.

Kelvin waves decay rapidly, emitting sound waves.

Proposed method enables excitation of specific Kelvin wave modes.

Abstract

We have theoretically investigated Kelvin waves of quantized vortex lines in trapped Bose-Einstein condensates. Counterrotating perturbation induces an elliptical instability to the initially straight vortex line, driven by a parametric resonance between a quadrupole mode and a pair of Kelvin modes of opposite momenta. Subsequently, Kelvin waves rapidly decay to longer wavelengths emitting sound waves in the process. We present a modified Kelvin wave dispersion relation for trapped superfluids and propose a simple method to excite Kelvin waves of specific wave number.