1. Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
2. Center for Quantum Information, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
3. Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest, Hungary
4. Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki út 8., H-1111 Budapest, Hungary
5. Department of Physics and Photon Science, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea