Theory of Higgs spectroscopy
Time-resolved pump-probe experiments recently attracted great interest, since they allow to detect hidden states and they provide new information on the underlying dynamics in solids in real time.
Recently, with the observation of a Higgs mode in superconductors it is now possible to investigate the superconducting order parameter, and thus the ground state, directly. By comparison with analytical calculations we now have a microscopic understanding of the Higgs mode in superconductors. After calculating the non-equilibrium response of s- and d-wave superconductors we show that such non-equilibrium Higgs spectroscopy opens a unique approach to distinguish between different symmetries of the condensate, even for new and unknown superconductors.