Josephson and persistent spin currents in Bose-Einstein condensates of magnons
Josephson and persistent spin currents in Bose-Einstein condensates of magnons
复制标题
约瑟夫森和磁振子玻色-爱因斯坦凝聚中的持续自旋流
DOI：
10.1103/physrevb.90.144419
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
and Daniel Loss
中科院分区：
文献类型：
--
作者：
Kouki Nakata;Kevin A. van Hoogdalem;Pascal Simon;and Daniel Loss
利用Aharonov-Casher（A-C）相，我们提出了磁振子在铁磁绝缘体中的准平衡玻色-爱因斯坦凝聚（BEC）中的约瑟夫森和持续自旋流的微观理论。从微观自旋模型，我们映射到一个Gross-Pitaevskii哈密顿量，我们推导出一个两态模型之间的弱耦合磁振子BEC的约瑟夫森结。然后，我们展示了如何获得交流（ac）约瑟夫森效应与磁振子以及宏观量子自陷在磁振子BEC。接下来，我们提出了如何控制直流（dc）约瑟夫森效应电使用的A-C相位，这是几何相位获得的磁振子在电场中移动。最后，我们介绍了一个磁振子BEC环，并表明持续磁振子BEC电流流动由于A-C相。针对持续磁振子BEC电流是一种稳定的磁偶极子流并产生电场的特点，提出了一种直接测量的方法。
Using the Aharonov-Casher (A-C) phase, we present a microscopic theory of the Josephson and persistent spin currents in quasiequilibrium Bose-Einstein condensates (BECs) of magnons in ferromagnetic insulators. Starting from a microscopic spin model that we map onto a Gross-Pitaevskii Hamiltonian, we derive a two-state model for the Josephson junction between the weakly coupled magnon-BECs. We then show how to obtain the alternating-current (ac) Josephson effect with magnons as well as macroscopic quantum self-trapping in a magnon-BEC. We next propose how to control the direct-current (dc) Josephson effect electrically using the A-C phase, which is the geometric phase acquired by magnons moving in an electric field. Finally, we introduce a magnon-BEC ring and show that persistent magnon-BEC currents flow due to the A-C phase. Focusing on the feature that the persistent magnon-BEC current is a steady flow of magnetic dipoles that produces an electric field, we propose a method to directly measure it experimentally.