Scientists from Singapore have presented optical atomic clocks based on lutetium ions that have surpassed all existing ones in precision. The results were published in the journal Nature on 23 September 2026.
A team from the Centre for Quantum Technologies (CQT) at the National University of Singapore (NUS), led by Murray Barrett, worked on the project for more than ten years. The researchers measured the transition frequency to 19 decimal places and achieved an uncertainty of 1 × 10^{-19} — the lowest figure among all optical atomic clocks to date.
To verify it, the scientists built two identical clocks and compared their rates. The agreement was 5,7 × 10^{-19} — the most precise comparison of clocks in history. "I am confident that what we have now is the most precise clock in the world," Barrett said.
The high sensitivity makes it possible to register gravitational effects: a difference in height of only 5 mm between two clocks on a single table. Such devices open the way to new tests of fundamental physics and to monitoring changes in gravity on Earth.
Lutetium, a rare-earth element, has proved particularly resistant to external influences such as temperature. The team, according to its own data, remains the only one using this element to build clocks. How will this precision affect the redefinition of the second in the coming years?
The development fits into global efforts to create a new time standard based on optical clocks, which are already hundreds of times more precise than caesium ones.
