Droplet crystal ground states of a dipolar Bose gas

TL;DR

This paper explores the complex ground states of a dipolar Bose gas, revealing droplet crystal formations, phase diagrams, and novel halo phases through analytical and numerical methods.

Contribution

It introduces an analytic model for droplet crystals and maps out the zero-temperature phase diagram, including the discovery of a halo phase.

Findings

Droplet crystal states form lattice patterns breaking rotational symmetry.

A coherent halo can surround droplet crystals in certain regimes.

The phase diagram is validated through numerical simulations.

Abstract

We show that the ground state of a dipolar Bose gas in a cylindrically symmetric harmonic trap has a rich phase diagram, including droplet crystal states in which a set of droplets arrange into a lattice pattern that breaks the rotational symmetry. An analytic model for small droplet crystals is developed and used to obtain a zero temperature phase diagram that is numerically validated. We show that in certain regimes a coherent low-density halo surrounds the droplet crystal giving rise to a novel phase with localized and extended features.