Researchers have created the first functional nuclear clock, using vibrations from radioactive thorium nuclei to measure time. The device marks a milestone after more than two decades of development and could eventually surpass the precision of current atomic clocks.
Thorsten Schumm at the Vienna University of Technology led the team that built the clock by embedding thorium atoms in a calcium fluoride crystal and tuning an ultraviolet laser to the nuclei’s energy transitions. The system runs at room temperature and requires no vacuum or extreme cooling, unlike atomic clocks.
The prototype loses tens of seconds every billion years, which is less stable than the best atomic clocks. Team members describe it as a proof of principle that can be refined with better lasers and electronics.
The clock has already been used to search for dark matter by monitoring tiny shifts in nuclear energy levels. Schumm called the achievement the culmination of 15 to 20 years of research.
