Radio-frequency spectroscopy of a strongly interacting spin-orbit coupled Fermi gas

TL;DR

This study combines experimental and theoretical approaches to analyze radio-frequency spectroscopy and pairing phenomena in a strongly interacting, spin-orbit-coupled Fermi gas of potassium-40 atoms near a Feshbach resonance, revealing characteristic shifts and anisotropic pairing signatures.

Contribution

It provides the first combined experimental and theoretical investigation of RF spectroscopy in a spin-orbit-coupled Fermi gas near resonance, highlighting the transition from atomic to molecular responses and anisotropic pairing effects.

Findings

Observation of characteristic blue and red shifts in spectroscopy with increasing spin-orbit coupling.

Prediction of a smooth transition from atomic to molecular responses in momentum-resolved spectroscopy.

Qualitative agreement between many-body theory and experimental spectroscopy data.

Abstract

We investigate experimentally and theoretically radio-frequency spectroscopy and pairing of a spin-orbit-coupled Fermi gas of $^{40}$K atoms near a Feshbach resonance at $B_{0}=202.2$ G. Experimentally, the integrated spectroscopy is measured, showing characteristic blue and red shifts in the atomic and molecular responses, respectively, with increasing spin-orbit coupling. Theoretically, a smooth transition from atomic to molecular responses in the momentum-resolved spectroscopy is predicted, with a clear signature of anisotropic pairing at and below resonance. Our many-body prediction agrees qualitatively well with the observed spectroscopy near the Feshbach resonance.