KATORI Innovative Space-Time

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Research Director: Hidetoshi Katori
Professor, Graduate School of Engineering, the University of Tokyo
Research Term: Oct 2010 - Mar 2016
Special Extention Period: Apr 2016 - Mar 2017
Grant Number: JPMJER1002


From antiquity, we, human beings, ceaselessly sought better clocks, started with astronomical observation such as the sun and the moon. By early this century, "cesium atomic clocks" achieved the uncertainty such that the clocks lose or gain less than one second over tens of millions of years. Such atomic clocks have become the basic technology to sustain our globalized daily activities. For example, they are utilized for today‘s global-scale high-speed broadband telecommunication networks and the worldwide navigation system through Global Navigation Satellite System (GNSS).

This research project aims to develop a novel atomic clock that surpasses cesium atomic clock that defines "a second" in the current SI unit. The research director, Hidetoshi Katori had invented an "optical lattice clock" that allows accessing far precise "atomic second" by simultaneously interrogating millions of ultracold atoms trapped in an optical lattice. The research project implements sophisticated laser cooling, quantum control, and state-of-the-art laser-stabilization technologies to develop "optical lattice clocks" targeting 18 digits of precision. This accuracy corresponds to less than one second uncertainty while operating the clocks over 13.8 billion years, i.e., the age of the universe.

The realization of the "optical lattice clocks" will allow reading out minute "space-time" curvature introduced by the gravitational field of the earth. From this viewpoint, our project alters the ‘daily’ concept of sharing clocks. Such clocks will find new applications in geodetic measurements, to be called "relativistic geodesy". The project also plans to explore fundamental aspects of physics by testing the constancy of the fundamental constants by comparing ultraprecise clocks.

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