Rabi-coupling-induced three-component quantum droplet in ultracold Bose gases

TL;DR

This paper proposes a new method to create stable three-component quantum droplets in ultracold Bose gases using Rabi coupling, with potential applications in multi-component quantum systems.

Contribution

It introduces a novel mechanism for forming multi-component quantum droplets through Rabi coupling, extending the understanding of droplet stabilization.

Findings

Stronger Rabi coupling increases the third component fraction but destabilizes the droplet.

Finite detuning can stabilize the droplet against Rabi coupling-induced instability.

Demonstrated in Na-Rb mixtures using thermodynamic and numerical methods.

Abstract

We uncover a new mechanism for realizing three-component quantum droplets in ultracold Bose gases, where only one inter-species interaction is attractive. In this scheme, the inter-species attraction leads to a self-bound binary droplet, and the third component joins through Rabi coupling with one component of the binary droplet. We find that a stronger Rabi coupling leads to a larger fraction of the third component, but also destabilizes the entire droplet due to the involvement of more repulsive forces. Such instability can be remedied by a finite detuning between the Rabi-coupled components. We demonstrate these results in realistic Na-Rb mixtures, using both thermodynamic analyses and numerical simulations based on extended Gross-Pitaevskii equations. Our work outlines a general route for stabilizing multi-component droplets by bridging an existing binary droplet with additional components via suitable single-particle fields.