Dipolar Bose gases: Many-body versus mean-field description

TL;DR

This paper uses diffusion Monte Carlo to accurately analyze zero-temperature dipolar Bose gases, revealing that mean-field models can be accurate if the dipole-dependent scattering length is properly included, and it proposes revised stability and collapse scenarios.

Contribution

It demonstrates that mean-field approaches can match many-body results when incorporating dipole-dependent scattering lengths, and it provides new insights into stability and collapse mechanisms.

Findings

Mean-field energies match DMC results with proper scattering length variation.

Revised stability diagrams differ from previous literature.

Collapse mechanisms are significantly different from earlier proposals.

Abstract

We characterize zero-temperature dipolar Bose gases under external spherical confinement as a function of the dipole strength using the essentially exact many-body diffusion Monte Carlo (DMC) technique. We show that the DMC energies are reproduced accurately within a mean-field framework if the variation of the s-wave scattering length with the dipole strength is accounted for properly. Our calculations suggest stability diagrams and collapse mechanisms of dipolar Bose gases that differ significantly from those previously proposed in the literature.