Roccuzzo S M, Gallemí A, Recati A, Stringari S
INO-CNR BEC Center and Dipartimento di Fisica, Università degli Studi di Trento, 38123 Povo, Italy and Trento Institute for Fundamental Physics and Applications, INFN, 38123 Trento, Italy.
Phys Rev Lett. 2020 Jan 31;124(4):045702. doi: 10.1103/PhysRevLett.124.045702.
Distinctive features of supersolids show up in their rotational properties. We calculate the moment of inertia of a harmonically trapped dipolar Bose-Einstein condensed gas as a function of the tunable scattering length parameter, providing the transition from the (fully) superfluid to the supersolid phase and eventually to an incoherent crystal of self-bound droplets. The transition from the superfluid to the supersolid phase is characterized by a jump in the moment of inertia, revealing its first order nature. In the case of elongated trapping in the plane of rotation, we show that the moment of inertia determines the value of the frequency of the scissors mode, which is significantly affected by the reduction of superfluidity in the supersolid phase. The case of an in-plane isotropic trapping is instead well suited to study the formation of quantized vortices, which are shown to be characterized, in the supersolid phase, by a sizeable deformed core, caused by the presence of the surrounding density peaks.
超固体的独特特征在其旋转特性中显现出来。我们计算了一个受到简谐捕获的偶极玻色 - 爱因斯坦凝聚气体的转动惯量，它是可调谐散射长度参数的函数，呈现出从（完全）超流相到超固相的转变，最终转变为自束缚液滴的非相干晶体。从超流相到超固相的转变以转动惯量的跃变为特征，揭示了其一级相变的性质。在旋转平面内拉长捕获的情况下，我们表明转动惯量决定了剪刀模频率的值，而该频率在超固相中超流性的降低会对其产生显著影响。相反，平面内各向同性捕获的情况非常适合研究量子涡旋的形成，结果表明，在超固相阶段，量子涡旋具有由周围密度峰值导致的相当大的变形核心。
