Japanese optical lattice clocks emerge as top contender for redefining the second

Optical lattice clocks developed by a Japanese scientist are now the leading candidates to replace the cesium-based definition of the second. The clocks, built by University of Tokyo professor Hidetoshi Katori, confine thousands of atoms in an "egg-carton" pattern formed by intersecting laser beams and measure the light frequency absorbed by atoms cooled near absolute zero. Using strontium or ytterbium, they drift by only about one second over 30 billion years, dramatically surpassing current standards.

The General Conference on Weights and Measures, scheduled to meet in France next month, will identify outstanding technical hurdles and could propose a new definition and rollout plan by 2030. To reach consensus, international teams must conduct rigorous cross-comparisons of different optical lattice and single-ion clocks. Remaining obstacles include ensuring the devices run without frequent maintenance and reducing their size for broader use. Adoption would enable more precise experiments in physics, astronomy, navigation, geodesy and resource exploration.