Counter-rotating vortices in miscible two-component Bose-Einstein condensates
Counter-rotating vortices in miscible two-component Bose-Einstein condensates
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DOI：
10.1103/physreva.88.063617
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发表时间：
2013-10
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
在煎饼形势下，理论上研究了可混溶的双组分玻色-爱因斯坦凝聚体中的反旋转涡旋，在这种凝聚体中，围绕重叠涡核的两个组分之间的超流反旋转。在Bogoliubov-de Gennes模型的线性稳定性分析中，我们证明了对旋涡对于分裂成多个涡是动态不稳定的。这种不稳定性是逆超流不稳定性的结果，它导致二元凝析油中两组分之间的相对流动松弛。这种特征行为与单组分玻色-爱因斯坦凝聚体中的多量子涡旋完全不同；由不稳定性产生的涡旋数目可以变得比反旋转涡旋的初始缠绕数更大。我们还通过数值求解Gross-Pitaevskii方程研究了不稳定性的非线性动力学。随着对旋涡缠绕数的增大，涡核外的涡对形核，非线性动力学发生了剧烈的变化。在两组分之间的相对旋转松弛后，不稳定性最终发展为湍流。
Counter-rotating vortices in miscible two-component Bose-Einstein condensates, in which superflows counter-rotate between the two components around the overlapped vortex cores, are studied theoretically in a pancake-shaped potential. In a linear stability analysis with the Bogoliubov-de Gennes model, we show that counter-rotating vortices are dynamically unstable against splitting into multiple vortices. The instability shows characteristic behaviors as a result of countersuperflow instability, which causes relaxation of relative flows between the two components in binary condensates. The characteristic behaviors are completely different from those of multiquantum vortices in single-component Bose-Einstein condensates; the number of vortices generated by the instability can become larger than the initial winding number of the counter-rotating vortex. We also investigate the nonlinear dynamics of the instability by numerically solving the Gross-Pitaevskii equations. The nonlinear dynamics drastically changes when the winding number of counter-rotating vortices becomes larger, which lead to nucleation of vortex pairs outside of the vortex core. The instability eventually develops into turbulence after the relaxation of the relative rotation between the two components.