Quantum Droplets of Dipolar Mixtures

Recently achieved two-component dipolar Bose-Einstein condensates open exciting possibilities for the study of mixtures of ultradilute quantum liquids. While nondipolar self-bound (without external confinement) mixtures are necessarily miscible with an approximately fixed ratio between the two densities, the density ratio for the dipolar case is free. Therefore, self-bound dipolar mixtures present qualitatively novel and much richer physics, characterized by three possible ground-state phases: miscible, symmetric immiscible, and asymmetric immiscible, which may in principle occur at any population imbalance. Self-bound immiscible droplets are possible due to mutual nonlocal intercomponent attraction, which results in the formation of a droplet molecule. Moreover, our analysis of the impurity regime shows that quantum fluctuations in the majority component crucially modify the miscibility of impurities. Our work opens intriguing perspectives for the exploration of spinor physics in ultradilute liquids, which should resemble to some extent that of He-4-He-3 droplets and impurity-doped helium droplets.

Automated summary

The recent achievement of two-component dipolar Bose-Einstein condensates has opened up exciting possibilities for studying mixtures of ultradilute quantum liquids, resulting in various ground-state phases. The formation of self-bound immiscible droplets is possible due to mutual nonlocal intercomponent attraction. Additionally, quantum fluctuations in the majority component critically modify the miscibility of impurities.