Laboratoire Kastler Brossel, Université Pierre et Marie Curie-Paris 6, École Normale Supérieure et CNRS, UPMC Case 74, 4 place Jussieu, 75005 Paris, France.
Science. 2011 Jun 3;332(6034):1167-70. doi: 10.1126/science.1202307.
A quantum fluid passing an obstacle behaves differently from a classical one. When the flow is slow enough, the quantum gas enters a superfluid regime, and neither whirlpools nor waves form around the obstacle. For higher flow velocities, it has been predicted that the perturbation induced by the defect gives rise to the turbulent emission of quantized vortices and to the nucleation of solitons. Using an interacting Bose gas of exciton-polaritons in a semiconductor microcavity, we report the transition from superfluidity to the hydrodynamic formation of oblique dark solitons and vortex streets in the wake of a potential barrier. The direct observation of these topological excitations provides key information on the mechanisms of superflow and shows the potential of polariton condensates for quantum turbulence studies.
当一种量子流体通过障碍物时，其行为与经典流体不同。当流速足够慢时，量子气体进入超流状态，障碍物周围既不会形成漩涡也不会形成波。对于更高的流速，有人预测，缺陷引起的微扰会导致量子涡旋的湍流发射和孤子的成核。我们利用半导体微腔中的激子极化激元相互作用玻色气体，报告了在势垒尾流中超流态向倾斜暗孤子和涡街的流体动力学形成的转变。这些拓扑激发现象的直接观察为超流机制提供了关键信息，并展示了极化激元凝聚物在量子湍流研究中的潜力。
