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Non-equilibrium spin dynamics in a trapped Fermi gas with effective spin-orbit interaction

Tudor D. Stanescu·Chuanwei Zhang·Victor Galitski
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Abstract

We consider a trapped atomic system in the presence of spatially varying laser fields. The laser-atom interaction generates a pseudospin degree of freedom (referred to simply as spin) and leads to an effective spin-orbit coupling for the fermions in the trap. Reflections of the fermions from the trap boundaries provide a physical mechanism for effective momentum relaxation and non-trivial spin dynamics due to the emergent spin-orbit coupling. We explicitly consider evolution of an initially spin-polarized Fermi gas in a two-dimensional harmonic trap and derive non-equilibrium behavior of the spin polarization. It shows periodic echoes with a frequency equal to the harmonic trapping frequency. Perturbations, such as an asymmetry of the trap, lead to the suppression of the spin echo amplitudes. We discuss a possible experimental setup to observe spin dynamics and provide numerical estimates of relevant parameters.

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Tudor D. Stanescu, Chuanwei Zhang, Victor Galitski. 2007-12-17. Non-equilibrium spin dynamics in a trapped Fermi gas with effective spin-orbit interaction. https://doi.org/10.1103/physrevlett.99.110403

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