Coherent and incoherent dynamics of a dilute exciton system

The kinetic equations for the polarization, the exciton distribution functi on and the anomalous correlation function of a system of coherently excited weakly interacting excitons are studied including the mean-field terms and their corresponding collision terms. These kinetic equations are solved by an adiabatic elimination of the anomalous correlation function. Our numeri cal results show besides the existence of the Bose-Einstein condensation (B EC) above the critical density also the slowing-down of the dephasing, when the critical density of the BEC is approached. (C) 2000 Elsevier Science L td. All rights reserved.