Single Spins in Diamond as Qubits and Magnetic Field Sensors
Dr. Boris Naydenov (Institut für Quantenoptik, Universität Ulm)

Nitrogen-Vacancy (NV) centers in diamond have been intensively studied by many research groups in the recent years since they are very good candidates for qubits for a solid state quantum computer at room temperature. Here we review their unique properties and report some of our latest experiments on NV centers for application in quantum information processing and magnetometry. These defects can be produced by ion implantation, where we found new ways to improve the efficiency of this process and also the stability of the implanted NVs.
We also demonstrate the coupling of two electron spins belonging to two distant NV centers. This pair, which can be used as a quantum register, was created by high energy focused ion implantation of nitrogen in ultra pure diamond. Double electron-electron resonance (DEER) measurements reveal 10 nm distance between the NVs.
Finally we developed a new implantation method for creating closely separated defects. By using this new technique we were able to entangle two coupled NVs centers. The preliminary experiments show a fidelity of about 95 %.