Kondo effect in optics of quantum dots

Anderson impurity model for semiconductor quantum dot is extended to take into account both particle and hole branches of charge excitations. It is shown that in dots with even number of electrons where the Kondo effect is absent in the ground state, novel midgap excitonic states emerge in the energy spectrum due to Kondo-type shake-up processes. The relevance of the model to rare earth ions adsorbed on metallic surfaces is discussed.