Transport Signatures of Non-equilibrium Criticality in Quenched Superfluids

We suggest employing recent advances in ultra-fast measurement to study
the growth of fluctuations as a second order phase transition is
rapidly traversed. Predictions are given for the time-resolved optical conductivity of
fermions quenched to a finite temperature superfluid transition, appropriate to cold
atom experiments or to K3C60 films. We demonstrate (i) the appearance of power laws in the optical conductivity, a signature of aging physics, (ii) growth in time of the low frequency conductivity as the fluctuation conductance channel is opened. Results are given for the dependence on distance from the critical point and for experimentally based quench protocols. All results depend on only a few material parameters.