Recent advances in exciton based quantum information processing in   quantum dot nanostructures
  Recent experimental developments in the field of semiconductor quantum dot spectroscopy will be discussed. First we report about single quantum dot exciton two-level systems and their coherent properties in terms of single qubit manipulations. In the second part we report on coherent quantum coupling in a prototype "two-qubit" system consisting of a vertically stacked pair of quantum dots. The interaction can be tuned in such quantum dot molecule devices using an applied voltage as external parameter. 
H. J. Krenner, S. Stufler, M. Sabathil, E. C. Clark, P. Ester, M.   Bichler, G. Abstreiter, J. J. Finley, A. Zrenner