1. Department of Physics, The University of Tokyo, Bunkyoku, Tokyo 113-0033, Japan
2. National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan
3. College of Science and Technology, Nihon University, Funabashi, Chiba 274-8501, Japan
4. CREST, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
5. Trans-scale Quantum Science Institute, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
6. Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA