Bragg spectroscopy of a strongly interacting Fermi gas

Understand

We present a comprehensive study of the Bose-Einstein condensate to Bardeen-Cooper-Schrieffer (BEC-BCS) crossover in fermionic $^6$Li using Bragg spectroscopy.

• A smooth transition from molecular to atomic spectra is observed with a clear signature of pairing at and above unitarity.
• These spectra probe the dynamic and static structure factors of the gas and provide a direct link to two-body correlations.
• We have characterised these correlations and measured their density dependence across the broad Feshbach resonance at 834 G.