Spin current generation and relaxation in a quenched spin-orbit-coupled Bose-Einstein condensate
Spin current generation and relaxation in a quenched spin-orbit-coupled Bose-Einstein condensate
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DOI：
10.1038/s41467-018-08119-4
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发表时间：
2018-10
影响因子：
16.6
通讯作者：
Chuan-Hsun Li;C. Qu;R. Niffenegger;Su-Ju Wang;M. He;D. Blasing;Abraham J. Olson;C. Greene;Y. Lyanda-Geller;Qi Zhou;Chuanwei Zhang;Yong P. Chen
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文献类型：
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作者：
Chuan-Hsun Li;C. Qu;R. Niffenegger;Su-Ju Wang;M. He;D. Blasing;Abraham J. Olson;C. Greene;Y. Lyanda-Geller;Qi Zhou;Chuanwei Zhang;Yong P. Chen
了解自旋-轨道耦合(SOC)和多体相互作用对自旋输运的影响在凝聚态物理和自旋电子学中具有重要意义。这个问题在电子等自旋载流子中得到了广泛的研究，但在电荷中性玻色子准粒子(包括它们的凝聚体)中几乎没有被探索过，这些粒子有望在宏观距离内实现相干的自旋输运。在这里，我们研究了合成SOC(由光拉曼耦合引起)和原子相互作用对原子玻色-爱因斯坦凝聚体(BEC)中自旋输运的影响，其中两个相互作用的自旋分量的自旋-偶极模(SDM，通过猝灭拉曼耦合而激活)构成了交变的自旋流。我们通过实验观察到，SOC显著提高了SDM的阻尼力，同时降低了热化程度(减少了凝结物的分数)。我们还观察到了BEC集体激发的产生，如形状振荡。我们的理论揭示了SOC修饰的干涉、不混溶和自旋分量之间的相互作用在自旋输运中起着至关重要的作用。
Understanding the effects of spin-orbit coupling (SOC) and many-body interactions on spin transport is important in condensed matter physics and spintronics. This topic has been intensively studied for spin carriers such as electrons but barely explored for charge-neutral bosonic quasiparticles (including their condensates), which hold promises for coherent spin transport over macroscopic distances. Here, we explore the effects of synthetic SOC (induced by optical Raman coupling) and atomic interactions on the spin transport in an atomic Bose-Einstein condensate (BEC), where the spin-dipole mode (SDM, actuated by quenching the Raman coupling) of two interacting spin components constitutes an alternating spin current. We experimentally observe that SOC significantly enhances the SDM damping while reducing the thermalization (the reduction of the condensate fraction). We also observe generation of BEC collective excitations such as shape oscillations. Our theory reveals that the SOC-modified interference, immiscibility, and interaction between the spin components can play crucial roles in spin transport.