Spin-Orbit Coupled Degenerate Fermi Gases

TL;DR

This paper reports the first experimental realization of a spin-orbit coupled degenerate Fermi gas, demonstrating key phenomena like spin dephasing, momentum asymmetry, and Lifshitz transition, advancing quantum simulation of topological states.

Contribution

It presents the first experimental observation of spin-orbit coupling effects in ultracold Fermi gases, including Fermi surface topology changes and spin dynamics.

Findings

Observation of spin dephasing in spin dynamics

Detection of momentum distribution asymmetry

Evidence of Lifshitz transition

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.