Quantum dynamics of single spins in semiconductor quantum dots

The goal of the project is to study and to manipulate single electron spins in charged quantum dots in the absence strong external magnetic fields. Control as well as read-out of the spin state is achieved optically via the trion feature. Special emphasize will be laid on the hyperfine coupling with the lattice atoms. Issues to be addressed are the formation and the degree of a nuclear polarization, the dynamics as well as spin coherence and entanglement of the combined nuclear-electron spin system. The study will be performed on epitaxial CdSe/ZnSe quantum dot heterostructures. Small volume size and low isotope abundance define here a novel situation where the electron is coupled to only a few hundred nuclear spins and where the spin splitting induced by the Overhauser field does not exceed markedly the spectral level broadening.