Work

Chiral quantum droplet in a spin-orbit-coupled Bose gas

Year: 2025

Type: article

Abstract: We report the formation of the chiral quantum droplet in a spin-orbit-coupled Bose gas, where the system turns to a self-bound droplet when moving towards a particular direction and remains gaseous otherwise. The chirality arises from the breaking of Galilean invariance by spin-orbit coupling, which enables the system to dynamically adjust its condensation momentum and spin polarization in response to its velocity. As a result, only towards a specific moving direction and beyond a critical velocity, the acquired spin polarization can trigger collective interactions sufficient for self-binding and drive a first-order transition from gas to droplet. We map out a phase diagram of the droplet, gas, and their coexistence for realistic spin-orbit-coupled $^{39}\mathrm{K}$ mixtures with tunable moving velocity and magnetic detuning. Our results reveal the emergence of chirality in spin-orbit-coupled quantum gases, which shed light on general chiral phenomena in moving systems with broken Galilean invariance.

Source: Physical Review A

DOI: 10.1103/8nvh-541r

Authors: Tianqi Luo, Xiaoling Cui

Institutions: Chinese Academy of Sciences, Institute of Physics, University of Chinese Academy of Sciences

Language: English

Topic: Cold Atom Physics and Bose-Einstein Condensates

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funder: National Natural Science Foundation of China

Awards: G3974951074, G7014496299