Dephasing times in quantum dots due to elastic LO phonon-carrier collisions

Interpretation of experiments on quantum dot (QD) lasers presents a challen ge: the phonon bottleneck, which should strongly suppress relaxation and de phasing of the discrete energy states, often seems to be inoperative. We su ggest and develop a theory for an intrinsic mechanism for dephasing in QDs: second-order elastic interaction between quantum dot charge carriers and L O phonons. The calculated dephasing times are of the order of 200 fs at roo m temperature, consistent with experiments. The phonon bottleneck thus does not prevent significant room temperature dephasing.