We develop a theory of the kinetics of the Bose-Einstein condensation of bosonic excitons interacting with a thermal bath of acoustic phonons. We emphasize several delicate aspects of the condensation kinetics within the framework of rate equations. We give detailed proofs about the existence and uniqueness of the solution with a condensate and illustrate details within exactly or almost exactly solvable models. In particular, we predict an exciton condensation time in ${\mathrm{Cu}}_2\mathrm{O}$ which is shorter than the lifetime of paraexcitons.

• Received 20 September 1999

DOI:https://doi.org/10.1103/PhysRevB.61.8823