Angular Momentum in Rotating Superfluid Droplets
Angular Momentum in Rotating Superfluid Droplets
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DOI：
10.1103/physrevlett.124.215301
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发表时间：
2020-05-26
影响因子：
8.6
通讯作者：
Vilesov, Andrey F.
中科院分区：
文献类型：
--
作者：
O'Connell, Sean M. O.;Tanyag, Rico Mayro P.;Vilesov, Andrey F.
旋转超流体液滴的角动量源自量子化涡流和毛细波，它们之间的相互作用仍有待揭示。在这里，使用自由电子激光器通过超快 X 射线衍射研究了孤立的亚微米超流体 He-4 液滴的旋转。衍射图案提供了对液滴及其所承载的涡流阵列的形态的同时访问。在胶囊状液滴中，涡旋形成扭曲的三角形晶格，而在椭圆形液滴中，涡旋沿着椭圆轮廓排列。涡流和毛细波的联合作用导致液滴形状接近以相同角速度旋转的经典液滴形状。这些发现得到了描述旋转超流体圆柱体的速度场和形状变形的密度泛函理论计算的证实。
The angular momentum of rotating superfluid droplets originates from quantized vortices and capillary waves, the interplay between which remains to be uncovered. Here, the rotation of isolated submicrometer superfluid He-4 droplets is studied by ultrafast x-ray diffraction using a free electron laser. The diffraction patterns provide simultaneous access to the morphology of the droplets and the vortex arrays they host. In capsule-shaped droplets, vortices form a distorted triangular lattice, whereas they arrange along elliptical contours in ellipsoidal droplets. The combined action of vortices and capillary waves results in droplet shapes close to those of classical droplets rotating with the same angular velocity. The findings are corroborated by density functional theory calculations describing the velocity fields and shape deformations of a rotating superfluid cylinder.