QUANTUM DYNAMICS OF EXCITON LASERS

We analyze the quantum dynamics of an exciton boser or laser - a devic e that generates a coherent population of nonequilibrium excitons. Aft er deriving the master equation for the exciton boser in the Born-Mark ov approximation, we use a stochastic wave function approach to demons trate that an approximately coherent state of excitons is generated fr om the vacuum state. The quantum theory that we develop allows us to a nalyze the effects of exciton-exciton interactions on coherent state f ormation. We demonstrate that the line width reduction obtained in a b oser is limited by the strength of these interactions.