Outline

Our daily lives, from smartphones to car navigation, rely heavily on accurate clocks. Currently, the most accurate are atomic clocks, which utilize the energy levels of electrons. Aiming for even higher accuracy, we are developing a nuclear clock that utilizes the energy levels of the atomic nucleus instead. Since the nucleus is highly immune to external noise, this clock is expected to surpass existing atomic clocks. Recently, we successfully trapped thorium ions—to be used in the nuclear clock—and developed laser spectroscopy techniques to precisely control their motion and internal states. We aim to apply nuclear clocks not only for frequency standards but also to unlock mysteries of the universe, such as searching for dark matter.

Fields

Interdisciplinary science, Physics, Engineering

Keywords

Quantum electronics, Quantum metrology, Nuclear clock, Thorium-229, Ion trap

Subjects

  • Development of trapped-ion nuclear clocks
  • Testing the constancy of fundamental physical constants
  • Direct precision laser spectroscopy of atomic nuclei

An ion trap apparatus for thorium ions used in nuclear clocks

Selected Publications

  • Shigekawa, Y., Yamaguchi, A., Tokoi, K., Sato, N., Kikunaga, H., Shirasaki, K., Kasamatsu, Y., Wada, M., and Haba, H.: “Lifetime of the singly charged 229Th nuclear isomer”, Nat. Phys. (2026).
  • Hiraki, T., Okai, K., Bartokos, M., Beeks, K., Fujimoto, H., Fukunaga, Y., Haba, H., Kasamatsu, Y., Kitao, S., Leitner, A., Masuda, T., Guan, M., Nagasawa, N., Ogake, R., Pimon, M., Pressler, M., Sasao, N., Schaden, F., Schumm, T., Seto, M., Shigekawa, Y., Shimizu, K., Sikorsky, T., Tamasaku, K., Takatori, S., Watanabe, T., Yamaguchi, A., Yoda, Y., Yoshimi, A., and Yoshimura, K.: “Controlling 229Th isomeric state population in a VUV transparent crystal”, Nat. Commun. 15, 5536 (2024).
  • Yamaguchi, A., Shigekawa, Y., Haba, H., Kikunaga, H., Shirasaki, K., Wada, M., and Katori, H.: “Laser spectroscopy of triply charged 229Th isomer for a nuclear clock”, Nature 629, 62 (2024).
  • Yamaguchi, A., Muramatsu, H., Hayashi, T., Yuasa, N., Nakamura, K., Takimoto, M., Haba, H., Konashi, K., Watanabe, M., Kikunaga, H., Maehata, K., Yamasaki, N. Y., and Mitsuda, K.: “Energy of the 229Th Nuclear Clock Isomer Determined by Absolute γ-ray Energy Difference”, Phys. Rev. Lett. 123, 222501 (2019).
  • Masuda, T., Yoshimi, A., Fujieda, A., Fujimoto, H., Haba, H., Hara, H., Hiraki, T., Kaino, H., Kasamatsu, Y., Kitao, S., Konashi, K., Miyamoto, Y., Okai, K., Okubo, S., Sasao, N., Seto, M., Schumm, T., Shigekawa, Y., Suzuki, K., Stellmer, S., Tamasaku, K., Uetake, S., Watanabe, M., Watanabe, T., Yasuda, Y., Yamaguchi, A., Yoda, Y., Yokokita, T., Yoshimura, M., and Yoshimura, K.: “X-ray pumping of the 229Th nuclear clock isomer”, Nature 573, 238 (2019).

Members

Members List
Name Position
Atsushi Yamaguchi Unit Leader
Keita Okamura JRA

Access & Contact

2-1 Hirosawa, Wako, Saitama 351-0198 JapanAccess

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