Transport of spin and mass at normal-superfluid interfaces in the unitary Fermi gas
Transport of spin and mass at normal-superfluid interfaces in the unitary Fermi gas
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DOI：
10.1103/physrevresearch.4.023231
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发表时间：
2019-12
影响因子：
4.2
通讯作者：
Ding Zhang;A. Sommer
中科院分区：
文献类型：
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作者：
Ding Zhang;A. Sommer
强相互作用费米气体中的输运为了解强相关费米子的非平衡行为提供了一个窗口。特别是，在有限温度下，强极化正常气体和弱极化超流体之间的界面为理解正常-超流体和正常-超导体界面的输运提供了一个模型。正常相的极化过度或超流体的极化不足会使系统失去平衡，导致穿过界面的传输电流。我们实现了幺正费米气体的唯象平均场模型，并研究了非平衡条件下质量和自旋在界面上的输运。我们计算的自旋电流，并显示如何可以理解的阈值在超流体中创建激发。我们发现，一个大的净（质量）电流的行为，以稀释过度极化在正常区域，并表明，净电流的结果主要来自反向Andreev反射。
Transport in strongly interacting Fermi gases provides a window into the non-equilibrium behavior of strongly correlated fermions. In particular, the interface between a strongly polarized normal gas and a weakly polarized superfluid at finite temperature presents a model for understanding transport at normal-superfluid and normal-superconductor interfaces. An excess of polarization in the normal phase or a deficit of polarization in the superfluid brings the system out of equilibrium, leading to transport currents across the interface. We implement a phenomenological mean-field model of the unitary Fermi gas, and investigate the transport of mass and spin across the interface under non-equilibrium conditions. We calculate the spin current and show how it can be understood in terms of the threshold for creating excitations in the superfluid. We find that a large net (mass) current acts to dilute excess polarization in the normal region, and show that the net current results primarily from reverse Andreev reflection.