Two-dimensional anisotropic vortex quantum droplets in dipolar Bose-Einstein condensates

TL;DR

This paper predicts and analyzes stable anisotropic vortex quantum droplets in dipolar Bose-Einstein condensates, demonstrating their creation, stability, and interactions through analytical and numerical methods, with potential experimental realization.

Contribution

It introduces the concept of anisotropic vortex quantum droplets in dipolar BECs, showing their stability, dynamics, and formation mechanisms, which were not known before.

Findings

Stable anisotropic vortex quantum droplets can be created with vortex axis perpendicular to dipole polarization.

AVQDs can follow magnetic field rotation up to a certain angular velocity.

Collisions can produce bound states with vortex-antivortex-vortex structures.

Abstract

Creation of stable intrinsically anisotropic self-bound states with embedded vorticity is a challenging issue. Previously, no such states in Bose-Einstein condensates (BECs) or other physical settings were known. Dipolar BEC suggests a unique possibility to predict stable anisotropic vortex quantum droplets (AVQDs). We demonstrate that they can be created with the vortex' axis oriented \emph{perpendicular} to the polarization of dipoles. The stability area and characteristics of the AVQDs in the parameter space are revealed by means of analytical and numerical methods. Further, the rotation of the polarizing magnetic field is considered, and the largest angular velocities, up to which spinning AVQDs can follow the rotation in clockwise and anti-clockwise directions, are found. Collisions between moving AVQDs are studied too, demonstrating formation of bound states with a vortex-antivortex-vortex structure. A stability domain for such stationary bound states is identified. Unstable dipolar states, that can be readily implemented by means of phase imprinting, quickly transform into robust AVQDs, which suggests a straightforward possibility for the creation of these states in the experiment.