Evolution of the normal state of a strongly interacting Fermi gas from a pseudogap phase to a molecular Bose gas

Phys Rev Lett. 2011 Feb 11;106(6):060402. doi: 10.1103/PhysRevLett.106.060402. Epub 2011 Feb 10.

Abstract

Wave-vector resolved radio frequency spectroscopy data for an ultracold trapped Fermi gas are reported for several couplings at T(c), and extensively analyzed in terms of a pairing-fluctuation theory. We map the evolution of a strongly interacting Fermi gas from the pseudogap phase into a fully gapped molecular Bose gas as a function of the interaction strength, which is marked by a rapid disappearance of a remnant Fermi surface in the single-particle dispersion. We also show that our theory of a pseudogap phase is consistent with a recent experimental observation as well as with quantum Monte Carlo data of thermodynamic quantities of a unitary Fermi gas above T(c).