title: Cooper pairing above the critical temperature in a unitary Fermi gas.
abstract: We present an ab initio determination of the spin response of the unitary Fermi gas. Based on finite temperature quantum Monte Carlo calculations and the Kubo linear-response formalism, we determine the temperature dependence of the spin susceptibility and the spin conductivity. We show that both quantities exhibit suppression above the critical temperature of the superfluid-to-normal phase transition due to Cooper pairing. The spin diffusion transport coefficient does not display a minimum in the vicinity of the critical temperature and drops to very low values D(s)≈0.8ħ/m in the superfluid phase. All these spin observables show a smooth and monotonic behavior with temperature when crossing the critical temperature T(c), until the Fermi liquid regime is attained at the temperature T(*), above which the pseudogap regime disappears.
authors.affiliation: Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662 Warsaw, Poland.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Wlazłowski
authors.forename: Piotr
authors.initials: P
authors.lastname: Magierski
authors.forename: Joaquín E
authors.initials: JE
authors.lastname: Drut
authors.forename: Aurel
authors.initials: A
authors.lastname: Bulgac
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Roche