Lutetium clocks have achieved record accuracy and comparison precision, making them promising candidates for future time standards and measurements of gravity.

An atomic clock built from the element lutetium at the Centre for Quantum Technologies (CQT) at the National University of Singapore (NUS) has set a new benchmark for timekeeping accuracy. Results published in Nature on show that the clock measured its transition frequency to 19 decimal places, yielding an uncertainty of 1 × 10⁻¹⁹, the lowest reported for any optical atomic clock to date.

“I am confident that what we have now is the most accurate clock in the world,” says team leader Murray Barrett, a CQT Principal Investigator and Associate Professor in the Department of Physics at the National University of Singapore.