Vienna team demonstrates self-stabilizing nuclear clock
Researchers in Vienna have built a nuclear clock that uses thorium nuclei rather than atomic electrons as its timekeeping reference. The device reportedly maintained stability for over 24 hours without relying on a conventional atomic clock. Such clocks could eventually improve precision measurement beyond current atomic timekeeping.
Researchers at TU Wien created a clock whose reference comes from thorium nuclei inside a specially made crystal. A laser drives transitions between two closely spaced nuclear energy states, and those nuclei then steady the laser’s frequency. The setup ran stably for more than a day without needing a standard atomic clock to correct it.
Earlier work had already pinpointed the thorium transition in 2024 and linked nuclear excitation to an optical atomic clock. This new step adds independent stabilization, a capability described as essential for a practical nuclear timekeeper.
If nuclear clocks mature, they could affect scientists who rely on precision measurement, as well as industries and public systems that depend on accurate timing, such as navigation and communications. Improved stability may enable tests of physical theories and more exact comparisons of time across locations. However, practical benefits would likely take years, and current atomic clocks would remain essential in the near term.