title: Spectroscopic signatures of nonequilibrium pairing in atomic fermi gases.
abstract: We determine the radio-frequency (rf) spectra for nonstationary states of a fermionic condensate produced by a rapid switch of the scattering length. The rf spectrum of the nonequilibrium state with constant BCS order parameter has two features in contrast with equilibrium where there is a single peak. The additional feature reflects the presence of excited pairs in the steady state. In the state characterized by periodically oscillating order parameter, the rf-absorption spectrum contains two sequences of peaks spaced by the frequency of oscillations. Satellite peaks appear due to a process where a rf photon in addition to breaking a pair emits or absorbs oscillation quanta.
authors.affiliation: Center for Materials Theory, Rutgers University, Piscataway, New Jersey 08854, USA.
authors.forename: M
authors.initials: M
authors.lastname: Dzero
authors.forename: E A
authors.initials: EA
authors.lastname: Yuzbashyan
authors.forename: B L
authors.initials: BL
authors.lastname: Altshuler
authors.forename: P
authors.initials: P
authors.lastname: Coleman