[1] Chalmers, Dept Microtechnol & Nanosci, S-41296 Gothenburg, Sweden
[2] Univ New Mexico, Ctr Quantum Informat & Control, Albuquerque, NM 87131 USA
[3] Univ Waterloo, Inst Quantum Comp, Waterloo, ON N2L 3G1, Canada
[4] Univ Waterloo, Dept Elect & Comp Engn, Waterloo, ON N2L 3G1, Canada
[5] Univ Queensland, Sch Phys Sci, Ctr Engineered Quantum Syst, St Lucia, Qld 4072, Australia