Radio-frequency response of strongly interacting Fermi gases at finite temperatures

摘要

The radio-frequency spectrum of the fermions in the unitary limit at finite temperatures is characterized by the sum-rule relations. We consider a simple picture where the atoms are removed by radio-frequency excitations from the strongly interacting states into a state of negligible interaction. We calculate the moments of the response function in the range of temperature 0.08_F< T<0.8E_F using auxiliary field Monte Carlo technique in which continuum auxiliary fields with a density-dependent shift are used. We estimate the effects of super-fluid pairing from the clock shift. We find a qualitative agreement with the pairing gap—pseudogap transition behavior. We also find within the quasiparticle picture that in order for the gap to come into quantitative agreement with the previously known value at T=0, the effective mass has to be m-1.43m. Finally, we discuss implications for the adiabatic sweep of the resonant magnetic field.