About Project

Katori Hidetoshi

Hidetoshi Katori (Program Manager)

Professor, Graduate School of Engineering,
The University of Tokyo

Chief Scientist, Quantum Metrology Laboratory,

The optical lattice clock, taken as a ridiculous idea in 2001, has come true and changed the game for building highly precise and stable atomic clocks. In this project, we will develop a space-time information platform by networking “optical lattice clocks”, which improve the uncertainty of atomic clocks used in GNSS (Global Navigation Satellite System) by three orders of magnitude. Such a platform will benefit future high-capacity network systems, navigation, and other services.



The achievement page have been updated.
The site visit of our project was held on June 4 at a video conference with Shimadzu Corporation as the host site.

An interview with Katori Program Manager is published in the March 2021 issue of Nikkei Electronics (P54).
Nikkei Electronics March 2021(Japanese)

Dr. Takamoto, assistant program manager,
Received the "3rd (2020) Teruo Hiruma Optical Science Award".

・Press release from Research Foundation
  for Opto-Science and Technology(Japanese)

・Press release from RIKEN(Japanese)

Happy new year.

Professor Katori of the program manager, received the
"Micius Quantum Prize 2020"
from the Micius Quantum Foundation.

・Press release from the Micius Quantum Foundation
・Website of the Micius Quantum Foundation

An international workshop on optical lattice clocks was held on December 3, 2020.
A workshop of the project was held on December 3.

The press release was issued by the National Institute of Advanced Industrial Science and Technology, which participated in the project.

"Achieved the world's first high operating rate operation of an optical lattice clock for half a year"

- Developed the world's most stable frequency standard optical lattice clock -
A video of a verification experiment of gravitational redshift conducted at Tokyo Skytree using a portable optical lattice clock created by RIKEN has been released on YouTube.
"Scientists use Tokyo Skytree to test Einstein’s theory of general relativity"

Professor Katori of the program manager, received the
"90th Anniversary Special Award"
from the Hattori Foundation.

・The University of Tokyo Press Release Site (Japanese)
・The Hattori Foundation website (Japanese)

The site visit of our project was held on August 21 at a video conference with NTT Basic Research Laboratories as the host site and the University of Tokyo as a subsite.
An English article was published in UTokyo FOCUS at the University of Tokyo.
"Einstein put to the test in Tokyo"

A paper on the Tokyo Skytree experiment was featured in Nature Photonics news & views.
"Earth-based clocks test general relativity"

An interview with Professor Katori appeared on the BBC Radio 4 program.
"The Bells of Old Tokyo by Anna Sherman"

An article about the Tokyo Skytree experiment was published in the June issue of "PHYSICS TODAY".
An article about the Tokyo Skytree experiment was published in the Japanese magazine "Newton July issue".
An article about the Sky Tree Experiment was published in the web magazine "It Ain's Magic" by The RIKEN Global Communications Team.
"Ultraprecise clocks and the Tokyo Skytree verify Einstein’s theory of relativity"

SIGMA Corporation has made a press release of participation in this project as an "industry-academia-government collaboration effort"(Japanese).
Press release was jointly conducted by the University of Tokyo, RIKEN, GSI, Shimadzu Corporation, Tobu Tower Skytree Corporation and JST.

"The world's first successful development of a portable optical lattice clock with 18-digit accuracy"
   ~ Verification of general relativity at Tokyo Skytree  ~

The world's first successful development of two portable optical lattice clocks with 18-digit accuracy. Using these two optical lattice clocks, we performed high-precision observations of gravitational redshift above and below the The Tokyo Skytree, and successfully verified general relativity on the ground.

Masao Takamoto, Ichiro Ushijima, Noriaki Ohmae, Toshihiro Yahagi, Kensuke Kokado, Hisaaki Shinkai & Hidetoshi Katori,
Test of General Relativity by a Pair of Transportable Optical Lattice Clocks,
Nature Photonics (2020),
DOI Number: 10.1038/s41566-020-0619-8. 

GO OUTLINE Related Site of Press Release (Japanese)

The web site of JST-Mirai Program (large-scale Type) Space-time information platform with a cloud of optical lattice clocks was started.

Press release was jointly conducted by NTT, the University of Tokyo, NTT East, RIKEN and JST.

Experimental demonstration of ultra-high precision optical frequency transfer via 240-km-long telecommunications fiber

It showed that the optical frequency of the optical lattice clock with world's highest performance can be transmitted over 200 km over optical fiber while maintaining its performance.

Tomoya Akatsuka, Takashi Goh, Hiromitsu Imai, Katsuya Oguri, Atsushi Ishizawa, Ichiro Ushijima, Noriaki Ohmae, Masao Takamoto, Hidetoshi Katori, Toshikazu Hashimoto, Hideki Gotoh, and Tetsuomi Sogawa,
Optical frequency distribution using laser repeater stations with planar lightwave circuits,
Optics Express, Volume 28, Issue 7, pp. 9186-9197 (2020).
A workshop of the project was held on January 21.
Our site visit by Supervisor was completed on December 2.

Contact us

Space-time information platform with a cloud of optical lattice clocks

2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656, JAPAN
Faculty of Engineering Bldg.9
Katori Laboratory
Room no.507

Tel: +81-3-5841-6845
Fax: +81-3-5841-6859
E-mail: jst.katori.hq(at)gmail.com











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Last update
June 29, 2021