Kinematics of the Doped Quantum Vortices in Superfluid Helium Droplets
Kinematics of the Doped Quantum Vortices in Superfluid Helium Droplets
复制标题
DOI：
10.1007/s10909-018-1869-4
复制
发表时间：
2018-05-01
影响因子：
2
通讯作者：
Vilesov, Andrey F.
中科院分区：
文献类型：
--
作者：
Bernando, Charles;Vilesov, Andrey F.
最近在直径为几百纳米的超流He液滴中观察到的量子涡旋涉及到由包含大量的氦原子的团簇装饰涡核，这些原子用作X射线造影剂。在这里，我们报告的运动学研究的组合涡团系统在一个圆柱和一个球。平衡状态，其特征在于由总角动量，L，被发现通过最小化的总能量，E，它的总和从液体的动能，由于涡旋和由于轨道旋转的团簇，以及在液滴中的团簇的溶剂化能。计算表明，在小质量团簇情况下，系统相对于旋转轴的平衡位移与裸涡接近。然而，当L减小到超过某个临界值（对于较重的团簇来说该值较大）时，位移会向表面区域分叉，在该区域系统的运动由团簇决定。此外，在更小的L，裸露的轨道集群变得积极有利，打开的可能性，旋涡脱离集群和湮灭在液滴的表面。
Recent observation of quantum vortices in superfluid He droplets measuring a few hundreds of nanometers in diameter involved decoration of vortex cores by clusters containing large numbers of Xe atoms, which served as X-ray contrast agents. Here, we report on the study of the kinematics of the combined vortex-cluster system in a cylinder and in a sphere. Equilibrium states, characterized by total angular momentum, L, were found by minimizing the total energy, E, which sums from the kinetic energy of the liquid due to the vortex and due to orbiting Xe clusters, as well as solvation energy of the cluster in the droplet. Calculations show that, at small mass of the cluster, the equilibrium displacement of the system from the rotation axis is close to that for the bare vortex. However, upon decrease in L beyond certain critical value, which is larger for heavier clusters, the displacement bifurcates toward the surface region, where the motion of the system is governed by the clusters. In addition, at even smaller L, bare orbiting clusters become energetically favorable, opening the possibility for the vortex to detach from the cluster and to annihilate at the droplet's surface.