Enhanced spontaneous emission from inhomogeneous ensembles of quantum dots is induced by short-range couplings

We study theoretically the spontaneous emission from an inhomogeneous ensemble of quantum dots in the weak excitation limit. We show that collective, superradiance-like effects lead to an enhanced emission rate in the presence of sufficiently strong coupling between the dots in agreement with experimental observations, which means that the quantum dot sample cannot be treated as an ensemble of individual emitters. We demonstrate also that the collective behavior of the quantum dot system relies on short-range interactions, while long-range dipole couplings are too weak to have any impact on the emission dynamics for a system with a realistic degree of inhomogeneity.