1. Department of Nuclear Engineering, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
2. Institute of Scientific and Industrial Research, Osaka University, Mihogaoka, Osaka 567-0047, Japan
3. Iwatani Corp., Amagasaki, Hyogo 661-0965, Japan
4. Academic Center for Computing and Media Studies, Kyoto University, Sakyo, Kyoto 606-8501, Japan
5. Quantum Science and Engineering Center, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan