Assistant Professor · Department of Physics, Graduate School of Science, The University of Tokyo
How precisely can an interferometer measure, and what sets that limit? I have worked across a wide range of them — kilometer-scale gravitational-wave detectors, milligram-scale mirrors held by light, interferometers that use atoms rather than photons — and the question has been the same each time. The floor is set by thermal fluctuation and by quantum mechanics itself, and past it lie the quantum behavior of macroscopic objects, dark matter, and whatever we have not yet found.
The ultimate sensitivity of a gravitational-wave detector is set, in the end, by quantum noise. How far can that limit be pushed down? I work on this through the optical spring and through the methods of quantum measurement.
Quantum noise is not only noise; it is also a signal. I turn the precision-measurement techniques built for gravitational-wave detectors onto milligram-scale mirrors, and ask how far an object of that size still obeys quantum mechanics.
Using matter waves instead of light gives a larger signal. To push the sensitivity of an atom interferometer I work on a phase-modulation readout scheme and analyze the limit it sets, and on applying it to gyroscopes that measure rotation.
An interferometer sensitive enough for gravitational waves will register other things too. With optical cavities and levitated nanoparticles I look for traces of dark matter that no experiment has caught so far.
The University of Tokyo Graduate School of Science Department of Physics
Assistant professor
The University of Tokyo Graduate School of Science Department of Physics
Specially appointed assistant professor
Tokyo Institute of Technology Institute of Innovative Research
Specially appointed assistant professor
Japan Society for the Promotion of Science
JSPS Research Fellow (DC1)
The University of Tokyo
Graduate School of Science Department of Physics
Doctor of Philosophy (Science)博士（理学）
The University of Tokyo
Faculty of Science Department of Physics
The University of Tokyo
College of Arts and Sciences Natural Sciences I
Physics Laboratory II · The University of Tokyo
Compulsory laboratory course for third-year undergraduates. In charge of the laser theme.