1. QuTech and Kavli Institute of NanoScience, Delft University of Technology, Lorentzweg 1, 2600 GA Delft, The Netherlands
2. Microsoft Station Q at Delft University of Technology, 2600 GA Delft, Netherlands
3. QuTech and Netherlands Organization for Applied Scientific Research (TNO), Stieltjesweg 1, 2628 CK Delft, The Netherlands
4. Center For Quantum Devices and Station Q Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
5. Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, 08193 Bellaterra, Barcelona, Catalonia, Spain
6. ICREA, Passeig de Lluı́s Companys 23, 08010 Barcelona, Catalonia, Spain