1. School of Physics and CRANN Institute, Trinity College Dublin, Dublin 2, Ireland
2. Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2AZ, U.K.
3. Quantum Technology Foundation (Thailand), 98 Soi Ari, Bangkok 10110, Thailand
4. Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400, Thailand