Title: Quantum Degeneracy Effects in Semiconductors

Abstract: The usual description of solids assumes a quasi-stationary limit and treats the interactions between quasi-particles as scattering events local in space and time, a key assumption for approximations such as the Random Phase Approximation or Boltzmann Kinetics. However, recent developments in time resolved spectroscopic techniques allow us now to probe condensed matter on time-scales short compared to the time between quasi-particle collisions. Thus it has become possible to observe deviations from "well established" theories in regimes of strongly correlated dynamics where the wave nature of quasi-particles becomes apparent in scattering events, large fluctuations of the mean-field order parameters are induced and high order correlations become dominant -- in particular, in degenerate Fermionic and Bosonic systems. In this talk I give a comprehensive account of recent advances, both experimental and theoretical, in our understanding of dynamical Coulomb correlations in semiconductors. I shall try to focus on the most important physics and, as much as possible, to give an intuitive picture of the new phenomena that have been observed.