Spin-Orbit Coupled Degenerate Fermi Gases

TLDR

Spin‑orbit coupling plays an increasingly important role in modern condensed matter physics, giving rise to topological insulators and superconductors. The study aims to quantum‑simulate spin‑orbit coupling with ultracold Fermi gases to explore these phenomena in a controllable setting. The experiment demonstrates a spin‑orbit coupled Fermi gas, revealing spin dephasing, momentum‑distribution asymmetry, and evidence of a Lifshitz transition, marking a step toward Majorana fermions.

Abstract

Spin-orbit coupling plays an increasingly important role in the modern condensed matter physics. For instance, it gives birth to topological insulators and topological superconductors. Quantum simulation of spin-orbit coupling using ultracold Fermi gases will offer opportunities to study these new phenomena in a more controllable setting. Here we report the first experimental study of a spin-orbit coupled Fermi gas. We observe spin dephasing in spin dynamics and momentum distribution asymmetry in the equilibrium state as hallmarks of spin-orbit coupling. We also observe evidences of Lifshitz transition where the topology of Fermi surfaces change. This serves as an important first step toward finding Majorana fermions in this system.