Optical absorption in semiconductor quantum dots: Nonlocal effects
  The optical absorption of a single spherical semiconductor quantum dot in an electrical field is studied taking into account the nonlocal coupling between the field of the light and the polarizability of the semiconductor. These nonlocal effects lead to a small size anf field dependent shift and broadening of the excitonic resonance which may be of interest in future high precision experiments. 
F. Thiele, Ch. Fuchs, and R. v. Baltz