Odd-petal states and persistent flows in spin-orbit-coupled Bose-Einstein condensates

TL;DR

This paper explores the phase diagram of spin-orbit-coupled Bose-Einstein condensates in a toroidal trap, revealing tunable odd-petal density states and persistent flow states with varying winding numbers, explained by a simple model.

Contribution

It introduces a detailed analysis of odd-petal density distributions and persistent flow states in spin-orbit-coupled BECs, highlighting their dependence on coupling strength and providing a simple explanatory model.

Findings

Azimuthally periodic density distributions with odd petals.

Persistent flow states with unit winding number differences.

Tunable states depending on spin-orbit coupling strength.

Abstract

We study the phase diagram of a Rashba spin-orbit-coupled Bose-Einstein condensate confined in a two-dimensional toroidal trap. In the immiscible regime we find an azimuthally periodic density distribution, with the periodicity highly tuneable as a function of the spin-orbit coupling strength and which favours an odd number of petals in each component. This allows for a wide range of states that can be created. We further show that in the miscible regime, both components possess states with persistent flows with a unit winding number difference between them and with the absolute values of these winding numbers depending on the spin-orbit coupling strength. All features of the odd-petal and the persistent flow states can be explained using a simple but effective model.