Pair correlations in the normal phase of an attractive Fermi gas

Abstract

In a recent paper (2019 Phys. Rev. A 99 , 053617), the total number of fermion pairs in a spin-balanced two-component Fermi gas of ^6 Li atoms was experimentally probed in the normal phase above the superfluid critical temperature, in order to investigate the sectors of pseudogap and preformed-pair in the temperature–coupling phase diagram. Here, we present a theoretical account of these experimental results in terms of an ab initio self-consistent t -matrix calculation, which emphasizes the role of the pair-correlation function between opposite-spin fermions at equilibrium. Good agreement is found between the available experimental data and the theoretical results obtained with no adjustable parameter.

Keywords

• superfluid Fermi gases
• pairing correlations
• preformed pairs