Quantum droplets in a dipolar Bose gas at a dimensional crossover

TL;DR

This paper investigates how beyond-mean-field effects stabilize a dipolar Bose gas confined to two dimensions, leading to self-bound droplets, with analytical insights into the effective interactions responsible for this stabilization.

Contribution

It provides a detailed analysis of beyond-mean-field corrections in a 2D dipolar Bose gas and introduces an effective three-body repulsion mechanism for droplet stabilization.

Findings

Formation of self-bound droplets at critical dipolar strength

Beyond-mean-field corrections act as effective three-body repulsion

Analytical demonstration of stabilization in strong confinement limit

Abstract

We study the beyond-mean-field corrections to the energy of a dipolar Bose gas confined to two dimensions by a box potential with dipoles oriented in plane. At a critical strength of the dipolar interaction the system becomes unstable on the mean field level. We find that the ground state of the gas is strongly influenced by the corrections, leading to formation of a self-bound droplet, in analogy to the free space case. Properties of the droplet state can be found by minimizing the extended Gross-Pitaevskii energy functional. In the limit of strong confinement we show analytically that the correction can be interpreted as an effective three-body repulsion which stabilizes the gas at finite density.