We consider a two-dimensional self-bound quantum droplet, which consists of a mixture of two Bose–Einstein condensates. We start with the ground state and then turn to the rotational response of this system, in the presence of an external (harmonic) potential. We identify various phases, depending on the atom number, the strength of the external confinement and the angular momentum. These include center of mass excitation, ghost vortices, as well as vortices of single and multiple quantization. According to our results, this is an excellent system for the study of superfluid states.

中文翻译：

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二维自束缚量子液滴的基态和旋转特性

我们考虑一个二维的自束缚量子滴，它由两种玻色-爱因斯坦凝聚物的混合物组成。我们从基态开始，然后在存在外部（谐波）电势的情况下转向该系统的旋转响应。我们根据原子序数，外部约束的强度和角动量来确定不同的相。这些包括质心激发，重影涡旋以及单次和多次量化的涡旋。根据我们的结果，这是研究超流体状态的极好系统。