Ultrawide dark solitons and droplet-soliton coexistence in a dipolar Bose gas with strong contact interactions

TL;DR

This paper derives analytical solutions for dark solitons in a dipolar Bose gas, explores their properties near a critical interaction strength, and demonstrates the coexistence of dark solitons within quantum droplets through numerical experiments.

Contribution

It introduces an analytical framework for dark solitons in dipolar Bose gases including beyond mean-field effects and reveals their coexistence with quantum droplets.

Findings

Soliton width diverges at a critical dipolar interaction value.

Existence of a non-zero density minimum soliton solution.

Coexistence of dark solitons within quantum droplets demonstrated.

Abstract

We look into dark solitons in a quasi-1D dipolar Bose gas and in a quantum droplet. We derive the analytical solitonic solution of a Gross-Pitaevskii-like equation accounting for beyond mean-field effects. The results show there is a certain critical value of the dipolar interactions, for which the width of a motionless soliton diverges. Moreover, there is a peculiar solution of the motionless soliton with a non-zero density minimum. We also present the energy spectrum of these solitons with an additional excitation subbranch appearing. Finally, we perform a series of numerical experiments revealing the coexistence of a dark soliton inside a quantum droplet.