Phase transition from straight into twisted vortex-lines in dipolar Bose-Einstein condensates

TL;DR

This paper investigates how dipole-dipole interactions induce a phase transition in vortex lines within dipolar Bose-Einstein condensates, transforming straight vortices into helical or snake-like structures due to instability caused by rotonization.

Contribution

It reveals a second-order-like phase transition from straight to twisted vortex lines driven by dipolar interactions and dipole orientation.

Findings

Identification of instability leading to vortex line deformation

Discovery of helical and snake-like vortex configurations

Analysis of the phase transition nature in dipolar BECs

Abstract

The non-local non-linearity introduced by the dipole-dipole interaction plays a crucial role in the physics of dipolar Bose-Einstein condensates. In particular, it may distort significantly the stability of straight vortex lines due to the rotonization of the Kelvin-wave spectrum. In this paper we analyze this instability showing that it leads to a second-order-like phase transition from a straight vortex-line into novel helical or snake-like configurations, depending on the dipole orientation.