Torque and Angular-Momentum Transfer in Merging Rotating Bose-Einstein Condensates
Torque and Angular-Momentum Transfer in Merging Rotating Bose-Einstein Condensates
复制标题
合并旋转玻色-爱因斯坦凝聚中的扭矩和角动量传递
DOI：
10.1103/physrevlett.124.105302
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发表时间：
2020
影响因子：
8.6
通讯作者：
Jin, Dafei
中科院分区：
文献类型：
--
作者：
Kanai, Toshiaki;Guo, Wei;Tsubota, Makoto;Jin, Dafei
当旋转的经典液滴合并在一起时，由于液滴界面处的粘性剪切流，角动量可以从一个平流输送到另一个。在玻色-爱因斯坦凝聚（BEC）等无粘量子流体中，相应的机制仍然是难以捉摸的。在这里，我们报告我们的理论研究的初始静态BEC合并与旋转BEC在三维空间中沿着旋转轴。我们发现，一个孤立片，类似于一个开瓶器，自发地出现在界面处。快速角动量转移以恒定的速率普遍成比例的初始角动量密度进行观察。引人注目的是，这种转移不一定涉及流体平流或量子化涡旋的漂移。我们发现，螺旋形结构可以施加一个扭矩，直接创建角动量在静态BEC和湮灭角动量在旋转BEC。揭示这种有趣的角动量传输机制可能有助于我们理解各种相干物质波系统，从芯片上的原子电子学到宇宙尺度上的暗物质BEC。
When rotating classical fluid drops merge together, angular momentum can be advected from one to another due to the viscous shear flow at the drop interface. It remains elusive what the corresponding mechanism is in inviscid quantum fluids such as Bose-Einstein condensates (BECs). Here we report our theoretical study of an initially static BEC merging with a rotating BEC in three-dimensional space along the rotational axis. We show that a solitonlike sheet, resembling a corkscrew, spontaneously emerges at the interface. Rapid angular-momentum transfer at a constant rate universally proportional to the initial angular-momentum density is observed. Strikingly, this transfer does not necessarily involve fluid advection or drifting of the quantized vortices. We reveal that the corkscrew structure can exert a torque that directly creates angular momentum in the static BEC and annihilates angular momentum in the rotating BEC. Uncovering this intriguing angular-momentum transport mechanism may benefit our understanding of various coherent matter-wave systems, spanning from atomtronics on chips to dark matter BECs at cosmic scales.