Excitations of a vortex line in an elongated dipolar condensate

TL;DR

This paper investigates the behavior and stability of vortex lines in elongated dipolar Bose-Einstein condensates, revealing a transition to self-bound vortex droplets stabilized by quantum fluctuations as dipolar interactions increase.

Contribution

It provides a detailed analysis of vortex excitations and stability in dipolar condensates, highlighting the transition to self-bound vortex droplets due to strong dipolar interactions.

Findings

Vortex lines become self-bound droplets with strong dipolar interactions.

The quasiparticle excitation spectrum reveals stability and instability regimes.

Strong dipolar interactions lead to dynamical quadrupolar instabilities.

Abstract

We characterise the properties of a vortex line in an elongated dipolar Bose-Einstein condensate. Increasing the strength of the dipole-dipole interactions (DDIs) relative to the short ranged contact interactions we find that the system crosses over to a self-bound vortex droplet stabilized from collapse by quantum fluctuations. We calculate the quasiparticle excitation spectrum of the vortex state, which is important in characterizing the vortex response, and assessing its stability. When the DDIs are sufficiently strong we find that the vortex is dynamically unstable to quadrupolar modes.