Non-Lorentzian spectral functions for Coulomb quantum kinetics

Numerical solutions of the Kadanoff-Baym equations with self-energies in second Born approximation are presented for electrons in a bulk semiconductor. The results are used to analyze in detail the two-time spectral function A(p, t(1), t(2)). In particular, (I) the damping of the spectral function is investigated over a broad density range both, for low and high temperatures; (II), A(p; t(2), t(2)) is compared to analytical expressions - an exponential and a recently proposed inverse hyperbolic cosine decay law; (III), the two analytical spectral functions are studied with respect to conservation of total energy, where for the inverse hyperbolic cosine an improved behavior is demonstrated.