NIST physicists have achieved new performance records with their experimental atomic clocks, which now tick with enough precision to improve timekeeping, navigation, and even detect faint signals from gravity, the early universe, and potentially dark matter. The clocks, which trap ytterbium atoms in optical lattices, have set new records in systematic uncertainty, stability, and reproducibility.
The clocks’ unprecedented reproducibility is particularly significant, as it shows their total error is now below the general ability to account for gravity’s effect on time here on Earth. This sensitivity to gravity can be turned into a tool to measure space-time distortions more precisely than ever before, with applications in relativistic geodesy and detecting signals from the early universe.
NIST’s ytterbium clocks now exceed the conventional capability to measure the geoid, or the shape of the Earth based on sea level surveys. Comparing clocks located far apart could resolve geodetic measurements to within 1 centimeter, better than the current state of the art of several centimeters.
The ytterbium atom is among potential candidates for the future redefinition of the second in terms of optical frequencies. NIST’s new clock records meet one of the international redefinition roadmap’s requirements, a 100-fold improvement in validated accuracy over the best clocks based on the current standard, the cesium atom.
NIST is building a portable ytterbium lattice clock with state-of-the-art performance that could be transported to other labs around the world for clock comparisons and to other locations to explore relativistic geodesy techniques.
Keywords: Metrology, Precision, Clocks, Gravity, Redshift
