Ultrafast Quantum Kinetics of Time-Dependent RPA-Screened Coulomb Scattering

We study the Coulomb quantum kinetics of relaxation and dephasing of an electron-hole gas in a semiconductor excited by a coherent femtosecond laser pulse. Our theory employs the full two-time-dependent RPA-screened Coulomb potential. The self-consistently calculated potential evolves from a bare potential to the well-known dynamically screened RPA potential for long times. The time dependence of the particle distributions, the interband polarization, and the potential are calculated. As a first application we study Rabi flopping with resonant femtosecond pulses.