Two-dimensional quantum droplets in binary quadrupolar condensates

TL;DR

This paper investigates the formation, stability, and properties of two-dimensional quantum droplets in binary Bose-Einstein condensates with magnetic quadrupole-quadrupole interactions, including analytical predictions and collision dynamics.

Contribution

It introduces a new model for 2D quantum droplets with quadrupolar interactions and provides analytical and numerical analysis of their stability, properties, and collision behavior.

Findings

Stable 2D quantum droplets with vortex and fundamental types identified.

Analytical formulas for area, chemical potential, and peak density derived.

Collision simulations reveal interaction dynamics of moving droplets.

Abstract

We study the stability and characteristics of two-dimensional (2D) quasi-isotropic quantum droplets (QDs) of fundamental and vortex types, formed by binary Bose-Einstein condensate with magnetic quadrupole-quadrupole interactions (MQQIs). The magnetic quadrupoles are built as pairs of dipoles and antidipoles polarized along the x-axis. The MQQIs are induced by applying an external magnetic field that varies along the x-axis. The system is modeled by the Gross-Pitaevskii equations including the MQQIs and Lee-Huang-Yang correction to the mean-field approximation. Stable 2D fundamental QDs and quasi-isotropic vortex QDs with topological charges S<4 are produced by means of the imaginary-time-integration method for configurations with the quadrupoles polarized parallel to the systems two-dimensional plane. Effects of the norm and MQQI strength on the QDs are studied in detail. Some results, including an accurate prediction of the effective area, chemical potential, and peak density of QDs, are obtained in an analytical form by means of the Thomas-Fermi approximation. Collisions between moving QDs are studied by means of systematic simulations.