RIKEN Center for Advanced Photonics Space-Time Engineering Research Team
Team Leader: Hidetoshi Katori (D.Eng.)
Research Summary

Clocks have served as a tool to share time, based on universal periodic phenomena; humankind relied upon the rotation of the earth from antiquity. The radiation from an atom provides us with far more accurate periodicity. The state-of-the-art atomic clocks sense the relativistic space-time curved by gravity, which reveal the difficulty of sharing time with others. Moreover, such clocks may be used to investigate the constancy of fundamental constants, where the foundation of the atomic clocks is anchored.
Optical lattice clocks raised the possibility of ultra-stable and accurate timekeeping by applying the "magic wavelength" protocol on optical lattices. Since the proposal of the scheme in 2001, the optical lattice clocks are being developed by more than 20 groups in the world, and the clocks are surpassing the uncertainty of the current SI second, becoming one of the most promising candidates for the future redefinition of the second.
Our team develops highly precise and transportable optical lattice clocks capable of long time operation by introducing advanced techniques in the field of atomic physics and quantum optics; we thus explore applications of "space-time engineering" that fully utilize the novel time resource provided by such clocks. For example, a transportable ultraprecise atomic clock, which may be taken out into the field, will function as a gravitational potential meter. We experimentally investigate the impact of such relativistic geodesy as a newer role for clocks in the future.
Main Research Fields
- Interdisciplinary Science & Engineering
Related Research Fields
- Engineering
Keywords
- Quantum electronics
- Atomic clock
- Quantum metrology
- Optical lattice clock
- Relativistic geodesy
Selected Publications
- 1.Tetsushi Takano, Masao Takamoto, Ichiro Ushijima, Noriaki Ohmae, Tomoya Akatsuka, Atsushi Yamaguchi, Yuki Kuroishi, Hiroshi Munekane, Basara Miyahara, and Hidetoshi Katori:
"Geopotential measurements with synchronously linked optical lattice clocks"
Nat. Photonics. 10, 662 (2016). - 2.Nils Nemitz, Takuya Ohkubo, Masao Takamoto, Ichiro Ushijima, Manoj Das, Noriaki Ohmae and Hidetoshi Katori:
"Frequency ratio of Yb and Sr clocks with 5×10-17 uncertainty at 150 seconds averaging time"
Nat. Photonics. 10, 258-261 (2016). - 3.Kazuhiro Yamanaka, Noriaki Ohmae, Ichiro Ushijima, Masao Takamoto, and Hidetoshi Katori:
"Frequency Ratio of199Hg and87Sr Optical Lattice Clocks beyond the SI Limit"
Phys. Rev. Lett. 114,230801 (2015). - 4.Ushijima, I., Takamoto, M., Das, M., Ohkubo, T. and Katori, H.:
"Cryogenic optical lattice clocks"
Nat. Photonics, doi:410.1038/nphoton.2015.5 (2015). - 5.Hidetoshi Katori:
"Optical lattice clocks and quantum metrology"
Nat. Photonics. 5, 203-210 (2011) - 6.Masao Takamoto, Tetsushi Takano, and Hidetoshi Katori:
"Frequency comparison of optical lattice clocks beyond the Dick limit"
Nat. Photonics. 5, 288-292 (2011) - 7.M. Takamoto, H. Katori, S. I. Marmo, V. D. Ovsiannikov, and V. G. Pal'chikov:
"Prospects for Optical Clocks with a Blue-Detuned Lattice"
Phys. Rev. Lett. 102, 063002 (2009) - 8.Tomoya Akatsuka, Masao Takamoto, and Hidetoshi Katori:
"Optical lattice clocks with non-interacting bosons and fermions"
Nat. Phys. 4, 954-959 (2008) - 9.M. Takamoto, F.-L. Hong, R. Higashi, and H. Katori:
"An optical lattice clock"
Nature 435, 321-324 (2005) - 10.Hidetoshi Katori, Masao Takamoto, V. G. Pal'chikov, and V. D. Ovsiannikov:
"Ultrastable Optical Clock with Neutral Atoms in an Engineered Light Shift Trap"
Phys. Rev. Lett. 91, 173005 (2003)
Recent Research Results
Related Links
Lab Members
Principal investigator
- Hidetoshi Katori
- Team Leader
Core members
- Masao Takamoto
- Senior Research Scientist
- Noriaki Ohmae
- Research Scientist
- Atsushi Yamaguchi
- Research Scientist
- Shoichi Okaba
- Special Postdoctoral Researcher
- Andrew George Hinton
- Special Postdoctoral Researcher
- Akiko Gomyo
- Visiting Scientist
Contact Information
Cooperation Center, W421
2-1 Hirosawa, Wako, Saitama 351-0198, Japan
Email: hkatori [at] riken.jp