Singapore team develops record-setting lutetium atomic clock

A research team in Singapore says it has built the world’s most accurate atomic clock using a single ion of the rare-earth element lutetium. The clock would lose one second every 260 billion years, according to the team at the National University of Singapore’s Centre for Quantum Technologies. That precision is about four times better than the previous record held by a calcium-ion clock developed by researchers in Wuhan, China.

The result also surpasses an aluminium-ion clock unveiled by the US National Institute of Standards and Technology. The decade-long project was described in a paper published in Nature. Team leader Murray Barrett said lutetium was unusually resistant to changes in temperature and magnetic fields.

A university statement quoted him as saying the clock would remain stable across extreme environments, from Death Valley to the Antarctic plateau. The researchers built two independent lutetium clocks and compared them directly to test their accuracy. After 200 hours of measurement, the clocks agreed to within 5.7 parts in 10¹⁹, which the researchers described as the most precise comparison between two atomic clocks reported so far.

Atomic clocks are important to GPS, telecommunications and navigation. The Singapore team said its work could help improve timekeeping and contribute to a future redefinition of the second. The clocks may also help scientists test general relativity and search for dark matter.

Lutetium can remain in an excited state for about a week, giving researchers more time to measure its frequency. The team’s next goal is to miniaturise the system for transport outside the laboratory.