Condensation kinetics of excitons

Photo-excited excitons are in the low-density regime approximately bosons. For low enough temperatures and high enough densities of the exciton gas, a non-equilibrium phase transition in the form of a Bose-Einstein condensation (BEC) can be expected. Various levels of the description of the kinetics of relaxation and condensation due to the coupling of the excitons to a cold reservoir of acoustic phonons. For non-interacting excitons a rate equation approach with the exciton Boltzmann equation can be used. This approach will be applied to investigate the possibility of a spontaneous condensation of quantum well micro-cavity polaritons. For interacting excitons the non-markovian quantum kinetics is required for the description of the BEC in order to incorporate the changes of the energy spectrum during the condensation self-consistently. Finally colored Langevin fluctuations can be used to calculate the phase diffusion of the condensate.