Masatoshi Kajita

National Institute of Information and Communications Technology, Japan

Title: Precision Frequency Measurement of Molecules

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Biography

Masatoshi Kajita Ph. D at U. of Tokyo with physics. After working at Institute of Molecular Science as a Post Doctor, he joined Communications Research Laboratory (present National Institute of Information and Communications Technology) at 1989. He was guest professor of Province University (France).

Abstract

The developments in physics are well correlated with the developments of new types of clocks; for example, the establishment of Newtonian mechanics is within 100 years after the drastic improvement of accuracy of clocks by the discovery of the periodicity of pendulums. The standard of the time & frequency is currently defined by the hyperfine transition frequency of Cs atoms (microwave), whose uncertainty is of the order of 10-16.  The uncertainty of 10-18 has been obtained with the optical transition frequencies of ions (trapped in a narrow area using rf-electric field) or neutral atoms (trapped by a standing wave of a laser light). The precision measurement of the atomic transition frequency is useful to develop physics beyond the standard model. For example, the precision measurement of the ratio between different atomic transition frequency is useful to detect the variation in fine structure constant. It is also useful to detect the variation in the proton-to-electron mass ratio. For this purpose, precision measurement of the molecular vibrational-rotational is useful. Particularly the pure vibrational transition frequencies (without change of any angular momentum quantum numbers), because the cancellations between energy shift at higher and lower states induced by the electric or magnetic fields are significant. The attainable uncertainties of pure vibrational transition frequencies of 15N2+ and 16O2+ molecular ions (trapped in a linear trap and sympathetically cooled with atomic ion, which is co-trapped) were estimated to be 10-18. The precision measurement of the vibrational transition of 40Ca19F molecules, which are laser cooled and trapped by a standing wave of a laser light, is also useful.