Terahertz Lightwave Control of Non-Equilibrium Phases and Collective Modes in Multi-Band Superconductors

摘要

A gauge-invariant density matrix approach is presented to describe the non-equilibrium dynamics of multi-band superconductors after photo-excitation. The derived gauge-invariant Bloch equations extend the Anderson pseudo-spin precession model by fully incorporating the center-of-mass motion of Cooper pairs. We also describe lightwave propagation effects inside a superconducting film by including the self-consistent interaction of the photo-excited superconducting system with the propagating electromagnetic field inside the superconductor using Maxwell's equations.