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arXiv · 2506.22198

Chiral Quantum Droplet in a Spin-Orbit Coupled Bose Gas

Tianqi Luo·Xiaoling Cui
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Abstract

We report the formation of 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 have mapped out a phase diagram of droplet, gas and their coexistence for realistic spin-orbit coupled 39K mixtures with tunable moving velocity and magnetic detuning. Our results have revealed the emergence of chirality in spin-orbit coupled quantum gases, which shed light on general chiral phenomena in moving systems with broken Galilean invariance.

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Tianqi Luo, Xiaoling Cui. 2025-06-27. Chiral Quantum Droplet in a Spin-Orbit Coupled Bose Gas. https://doi.org/10.1103/8nvh-541r

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