Overview
- The Centre for Quantum Technologies at the National University of Singapore reported on 23 September that its lutetium-based optical clock achieved a fractional uncertainty of about 1×10^-19 and a frequency readout to 19 decimal places.
- The team built two independent Lu+ clocks and compared them directly, finding their ticks matched to the 19th digit in the most precise clock-to-clock verification published to date.
- Each clock uses a single charged 176Lu+ ion probed by an 848 nm laser and employs long correlation spectroscopy runs plus a hyperfine-averaging scheme to suppress systematic shifts.
- At the 10^-19 precision level the clocks detect gravitational time dilation across millimetre-scale height differences, which complicates inter-laboratory benchmarking and pushes the group to make the system transportable.
- Because lutetium’s transition is unusually insensitive to temperature and magnetic-field shifts, the team argues the element is a strong candidate for next-generation optical standards with uses in geodesy and tests of fundamental physics.