Experimental realization of a two-dimensional synthetic spin-orbit coupling in ultracold Fermi gases

TL;DR

This paper reports the experimental creation of a two-dimensional synthetic spin-orbit coupling in ultracold Fermi gases, enabling exploration of high-dimensional topological phenomena with controlled atomic systems.

Contribution

It demonstrates the first realization of 2D synthetic SOC in ultracold atoms using a three-laser scheme, advancing the control over topological states in quantum gases.

Findings

Successful creation of 2D SOC in ultracold Fermi gases

Observation of a controllable Dirac point in the energy spectrum

Use of spin injection rf spectroscopy to probe spin-resolved dispersions

Abstract

Spin-orbit coupling (SOC) is central to many physical phenomena, including fine structures of atomic spectra and quantum topological matters. Whereas SOC is in general fixed in a physical system, atom-laser interaction provides physicists a unique means to create and control synthetic SOC for ultracold atoms \cite{Dalibard}. Though significant experimental progresses have been made, a bottleneck in current studies is the lack of a two-dimensional (2D) synthetic SOC, which is crucial for realizing high-dimensional topological matters. Here, we report the experimental realization of 2D SOC in ultracold $^{40}$K Fermi gases using three lasers, each of which dresses one atomic hyperfine spin state. Through spin injection radio-frequency (rf) spectroscopy, we probe the spin-resolved energy dispersions of dressed atoms, and observe a highly controllable Dirac point created by the 2D SOC. Our work paves the way for exploring high-dimensional topological matters in ultracold atoms using Raman schemes.