First Nuclear Clocks Tick by Listening to an Atom's Core
Thorium 229 based nuclear clocks
Two independent teams—Thorsten Schumm's group at TU Wien and Shiqian Ding's at Tsinghua University—have built the first working nuclear clocks, using a feedback loop to lock a laser to the thorium-229 nucleus's uniquely low-energy transition. Reported in June 2026, these clocks promise rugged, portable timekeeping and a sensitive new probe for dark matter and shifting fundamental constants.
In some types of measurements, we're already outperforming all atomic clocks.