Higgs Oscillations in time-resolved Optical Conductivity

Kumar A, Kemper AF
Phys. Rev. B 100, 174515 (2019)


The characterization of a superconducting state in a pump driven non-equilibrium state requires careful attention in the time domain. We calculate time-resolved optical conductivity for a pumped superconducting state using a non-equilibrium Keldysh approach. Through functional derivation, the optical conductivity is obtained with full vertex corrections; we use it to characterize the transient superconducting state. The transient optical conductivity shows the suppression of the superconducting order parameter in the time domain; the subsequent recovery of the order parameter exhibits oscillatory behavior which corresponds to the Higgs amplitude mode.