Electro-optical properties of semiconductor quantum dots: Application to quantum information processing

A detailed analysis of the electro-optical response of single as well as coupled semiconductor quantum dots is presented. This is based on a realistic—i.e., fully tridimensional—description of Coulomb-correlated few-electron states, obtained via a direct-diagonalization approach. More specifically, we investigate the combined effect of static electric fields and ultrafast sequences of multicolor laser pulses in the few-carrier, i.e., low-excitation regime. In particular, we show how the presence of a properly tailored static field may give rise to significant electron-hole charge separation; these field-induced dipoles, in turn, may introduce relevant exciton-exciton couplings, which are found to induce significant—both intra-dot and interdot—biexcitonic splittings. We finally show that such few-exciton systems constitute an ideal semiconductor-based hardware for an all optical implementation of quantum information processing.