Spin-resolved Quantum Gas Microscopy of 2D Fermi Gases in the Continuum

In this work, we demonstrate spin- and charge-resolved quantum gas microscopy of a strongly interacting two-dimensional Fermi gas. This approach provides real-space access to Cooper pair formation and enables a systematic investigation of correlations throughout Bose–Einstein condensate (BEC) to a Bardeen–Cooper–Schrieffer (BCS) superfluid crossover. From doublon fractions we can determine the contact with high accuracy, establishing a direct link between microscopic observables and macroscopic thermodynamics. Spatially resolved measurements of spin and distributions are used to derive the magnetic and static structure factors, which reveal a continuous transformation of number statistics from super-Poissonian in the BEC limit to sub-Poissonian in the Fermi-liquid regime. We detect the onset of long-range spin correlations and identify signatures of collective sound modes in finite-temperature density fluctuations. Furthermore, our experimental techniques also open the door to investigations of spin-imbalanced Fermi gases and the physics of Fermi polarons. By tuning the imbalance between the spin species, impurity–medium interactions and dressing effects can be explored at the single-particle level. These results provide a comprehensive map of the phase diagram of two-dimensional strongly interacting fermions.