Non-equilibrium exciton dynamics in model systems

Ultrashort laser pulses are used to observe time resolved dynamics in condensed matter systems. The typical time resolved measurements include reflection, transmission and absorption using pump-probe spectroscopy where a pump pulse excites the system into a non-equilibrium state and the subsequent probe pulse measures the dynamical relaxation of the system as a function of a delay time. We study the two-particle properties of a model interacting two-band Hamiltonian by solving the non-equilibrium Bethe-Salpeter equation for the correlation function. This allows us to study the dynamics of electron-hole bound states i.e. excitons, in model systems where the time translational invariance is broken by the pump pulse.