Countersuperflow instability in miscible two-component Bose-Einstein condensates
Countersuperflow instability in miscible two-component Bose-Einstein condensates
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DOI：
10.1103/physreva.83.063602
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发表时间：
2011-06
影响因子：
2.9
通讯作者：
S. Ishino;M. Tsubota;H. Takeuchi
中科院分区：
文献类型：
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作者：
S. Ishino;M. Tsubota;H. Takeuchi
我们从理论上研究了反超流的不稳定性，即均匀二组分玻色-爱因斯坦凝聚中的两个反向传播的可混溶超流。当逆流的相对速度超过临界值时，逆超流不稳定性会导致超流体之间的相互摩擦，从而导致两种冷凝物之间的动量交换。由于不稳定性的非线性发展，动量交换导致涡环从特征密度模式中成核。涡环的膨胀极大地加速了动量交换，导致由涡旋间相互作用和环之间的涡旋重新连接引起的高度非线性状态。对于两个组分之间足够大的相互作用，涡环的快速膨胀导致各向同性湍流，并且两个冷凝物的整体相对运动松弛。湍流中的最大涡线密度与相对速度的平方成正比。
We study theoretically the instability of countersuperflow, i.e., two counterpropagating miscible superflows, in uniform two-component Bose-Einstein condensates. Countersuperflow instability causes mutual friction between the superfluids, causing a momentum exchange between the two condensates, when the relative velocity of the counterflow exceeds a critical value. The momentum exchange leads to nucleation of vortex rings from characteristic density patterns due to the nonlinear development of the instability. Expansion of the vortex rings drastically accelerates the momentum exchange, leading to a highly nonlinear regime caused by intervortex interaction and vortex reconnection between the rings. For a sufficiently large interaction between the two components, rapid expansion of the vortex rings causes isotropic turbulence and the global relative motion of the two condensates relaxes. The maximum vortex line density in the turbulence is proportional to the square of the relative velocity.