Vortex to Rotons Transition in Dipolar Bose-Einstein Condensates

TL;DR

This paper explores the transition from vortex states to roton-like excitations in dipolar Bose-Einstein condensates, revealing a connection between topological defects and roton minima in the dispersion relation.

Contribution

It demonstrates the explicit link between solitary vortex waves and roton excitations, supporting Feynman's hypothesis in dipolar BECs.

Findings

Existence of two-dimensional solitary waves with vortices in dBECs

Transition from vortex to vortex-free solitons linked to roton minima

Support for rotons as vortex excitation remnants

Abstract

Recent experimental advancements enabled the creation of various systems exhibiting superfluid behavior, with one notable achievement being the development of dipolar Bose-Einstein condensates (dBECs). When confined along one or more spatial dimensions, these condensates exhibit a dispersion relation reminiscent of superfluid liquid helium, featuring a roton-like minimum. This study investigates the existence of two-dimensional solitary waves in dBECs characterised by topological defects (quantised vortices) and their transition to vortex-free Jones-Roberts solitons. The explicit connection between solitary waves and roton excitation is demonstrated, supporting Feynman's hypothesis regarding the nature of rotons as fading vortex excitations.