1. Dipartimento di Fisica, Università di Napoli Federico II, Monte Sant'Angelo - Via Cintia, I-80126 Napoli, Italy
2. CNR-SPIN, Monte S. Angelo, Via Cintia, I-80126 Napoli, Italy
3. Dipartimento di Ingegneria Elettrica e delle Tecnologie dell'Informazione, Università di Napoli Federico II, Via Claudio, I-80125 Napoli, Italy
4. Institute of Solid State Physics (ISSP RAS), Chernogolovka, Moscow Region 142432, Russia
5. Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119991, Russia
6. Leiden Institute of Physics, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
7. SeeQC-eu, Via dei Due Macelli 66, 00187 Rome, Italy
8. HYPRES, Inc., 175 Clearbrook Road, Elmsford, New York 10523, USA
9. Faculty of Physics, National Research University Higher School of Economics, Moscow, Russia