# Strongly correlated quantum droplets in quasi-1D dipolar Bose gas

## TL;DR

This paper investigates strongly interacting dipolar bosons in a quasi-1D system, revealing the existence of quantum droplets and proposing a new density equation that captures fermionization effects, expanding understanding of quantum phase stability.

## Contribution

It introduces a novel density amplitude equation incorporating Lieb-Liniger energy for strongly repelling bosons, and demonstrates the formation of quantum droplets in a quasi-1D dipolar Bose gas.

## Key findings

- Discovery of quantum droplets in strongly coupled dipolar bosons.
- Development of a new density equation accounting for fermionization.
- Identification of regimes where Lee-Huang-Yang correction is not applicable.

## Abstract

We exploit a few- to many-body approach to study strongly interacting dipolar bosons in the quasi-one-dimensional system. The dipoles attract each other while the short range interactions are repulsive. Solving numerically the multi-atom Schr\"{o}dinger equation, we discover that such systems can exhibit not only the well known bright soliton solutions but also novel quantum droplets for a strongly coupled case. For larger systems, basing on microscopic properties of the found few-body solution, we propose a new equation for a density amplitude of atoms. It accounts for fermionization for strongly repelling bosons by incorporating the Lieb-Liniger energy in a local density approximation and approaches the standard Gross-Pitaevskii equation (GPE) in the weakly interacting limit. Not only does such a framework provide an alternative mechanism of the droplet stability, but it also introduces means to further analyze this previously unexplored quantum phase. In the limiting strong repulsion case, yet another simple multi-atom model is proposed. We stress that the celebrated Lee-Huang-Yang term in the GPE is not applicable in this case.