Precision thermodynamics of the strongly interacting cold atomic Fermi gas in two spatial dimensions*

The two-species Fermi gas in two spatial dimensions (2D) with an attractive short- range interaction undergoes at zero temperature a crossover from a Bardeen- Cooper-Schrieffer (BCS) condensate to a Bose-Einstein condensate (BEC) as a function of the scattering length. This system exhibits features that are unique to two dimensions, including the presence of a bound state for an arbitrarily weak attractive interaction and the Berezinskii-Kosterlitz-Thouless character of the phase transition to a superfluid below a critical temperature. Of particular interest is the strongly correlated regime which lies between the BCS and BEC limits. Using finite-temperature auxiliary-field quantum Monte Carlo (AFMC) calculations, performed on discrete lattices and extrapolated to the continuum limit, we investigate the thermodynamic behavior of the 2D system across the strongly interacting regime. In particular, we discuss the extent of a pseudogap regime, in which pairing correlations survive above the critical temperature for superfluidity. We also discuss the calculation of dynamical observables, such as the single-particle spectral function, through the use of numerical analytic continuation.