On dynamics beyond time-dependent mean-field theories

Résumé : This thesis presents various quantal approaches to include collisional correlation on top of time-dependent mean-field theories. We are mainly interested in time-dependent nonlinear phenomena that are studied in the (real-time) time-dependent density functional theory (TDDFT) framework.We have developed methods that could be tractable in realistic systems in order to include dissipative features that stem from electron-electron collision. These approaches are reviewed and tested in model electronic systems. The far end of these methods is the exploration of dynamical processes in multielectronic systems, after an intense excitation which can lead to dissipative effects.