Hollow cylindrical droplets in a very strongly dipolar condensate

TL;DR

This paper demonstrates the existence of hollow cylindrical metastable droplets with ring topology in a strongly dipolar Bose-Einstein condensate, revealing novel topological states enabled by long-range dipole interactions.

Contribution

It introduces a new topologically nontrivial state in dipolar BECs, showing the formation and stability of hollow cylindrical droplets under specific trapping conditions.

Findings

Hollow cylindrical droplets can form in strongly dipolar BECs.

These droplets are metastable and weakly stable.

The study uses numerical simulations with mean-field and Lee-Huang-Yang interactions.

Abstract

A harmonically trapped Bose-Einstein condensate (BEC) leads to topologically trivial compact states. Because of the long-range nonlocal dipole-dipole interaction, a strongly dipolar BEC revealed many novel phenomena. Here we show that in a strongly dipolar BEC one can have a hollow cylindrical quasi-one-dimensional metastable droplet with ring topology while the system is trapped only in the $x$-$y$ plane by a harmonic potential and a Gaussian hill potential at the center and untrapped along the polarization $z$ axis. In this numerical investigation we use the imaginary-time propagation of a mean-field model where we include the Lee-Huang-Yang interaction, suitably modified for dipolar systems. Being metastable, these droplets are weakly stable and we use real-time propagation to investigate its dynamics and establish stability.