1. PHI, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
2. IPE, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany
3. LFNAE, Universidad de Zaragoza, 50009 Zaragoza, Spain
4. INFN-Sezione di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy
5. INT, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany
6. RQC, National University of Science and Technology MISIS, 119049 Moscow, Russia
7. JARA Institute for Quantum Information (PGI-11), Forschungszentrum Jülich, 52425 Jülich, Germany