Revealing the Microscopics of Strongly Interacting 2D Fermi Gases in the Continuum

In this work, we demonstrate spin- and charge-resolved quantum gas microscopy of a two-dimensional strongly interacting Fermi gas in the continuum. This technique enables direct, real-space observation of Cooper pairing and allows for a complete characterization of correlations throughout the Bose–Einstein condensate (BEC) to Bardeen–Cooper–Schrieffer (BCS) crossover. By measuring the onsite doublon fractions we can extract the contact with high precision, establishing a direct link between microscopic observables and macroscopic thermodynamics. Moreover, measurements of spin and charge distributions allow us to construct the magnetic and static structure factors, revealing the smooth evolution of number fluctuations from super-Poissonian in the molecular BEC regime to sub-Poissonian in the Fermi-liquid regime. We observe the emergence of long-range spin correlations and the effects of sound modes on fluctuations at finite temperature. These results provide a comprehensive map of the phase diagram of two-dimensional strongly interacting fermions.