In the JST Strategic Creative Research Promotion Project, the research groups of Professor Hidetoshi Katori (Senior Researcher, RIKEN) of the Graduate School of Engineering, the University of Tokyo, and Nils Nemitz, International Research Fellow of RIKEN, have different atoms. Announced that it succeeded in comparing the optical grid clock using the above with the world's highest accuracy and short measurement time.

 Currently, a cesium atomic clock is used to measure time, and the error is 3000 second in 1 million years.Atomic clocks that use the vibration of light include "optical clocks," which are 100 times more accurate than cesium atomic clocks.As a method to realize this optical clock, there is an optical lattice clock that uses laser light, which was proposed by Professor Hidetoshi Katori in 2001.To confirm the high-precision measurement of time, it is necessary to compare the frequency ratio with two atomic clocks with the same or higher accuracy, but in the past it took several months to measure.

The research group uses an optical lattice clock technique that captures and measures ytterbium and strontium atoms in an optical lattice made of a special wavelength called "magic wavelength" to significantly reduce the measurement time and reduce the frequency. I succeeded in comparing.As a result, we have now determined the frequency ratio with an accuracy far exceeding the 137-second realization accuracy of the International System of Units, setting a new record for the accuracy of different atomic clock comparisons so far.Even after the age of the universe (1 billion years) has passed, the error is less than 90 second.In addition, by further improving the stability of the optical lattice clocks, we have achieved a comparison between the two clocks in 150 seconds, which is 2 times faster than the fastest measurement time so far.

Such ultra-precise watch comparisons can be a driving force for the transition to the new definition of "seconds" while ensuring reliability as a next-generation watch.It is also expected to function as a highly sensitive search device that opens up new physics by enabling the search for physical phenomena that cannot be observed by existing methods.

Tokyo University

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The University of Tokyo was established in 1877 (Meiji 10) by integrating the Tokyo Kaisei School and the Tokyo Medical School.Since its establishment, it has developed education and research in a unique way in the world as a leading university in Japan and an academic center for the fusion of East and West cultures.As a result, many human resources have been produced in a wide range of fields, and many research achievements […]

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