The first ticking ‘nuclear clocks’ are here — what can they do?

The clocks use a precise laser to measure transitions inside the nuclei of thorium-229 atoms. Credit: Getty Two teams of physicists have made the world’s first nuclear clocks . These radical new devices use fluctuations in the energy states of an atom’s nucleus to keep time, rather than those of its electrons, which atomic clocks currently use to define the length of a second. Working out how to extract the ‘tick’ from a nucleus and use it to keep time has taken more than 20-years . Nuclear clocks should be more robust and portable than the best available clocks today because nuclei are hard to perturb and protected in a crystal. As well as potentially someday being more precise, they also give physicists an unprecedented way to probe the forces at play inside a nucleus. Two nuclear clocks have been presented in two studies, which were posted on the preprint server arXiv on 3 and 7 June, by teams in Europe 1 and China 2 . They show that nuclear clocks have gone from a system with “potential” to “a functioning precision instrument” that can be used to search for new physics, says Gilad Perez, a theoretical physicist at the Weizmann Institute of Science in Rehovot, Israel. Creating a nuclear clock is “a dream come true”, says Thorsten Schumm, an atomic physicist at the Vienna University of Technology and a lead member of the European team. Until recently the field had been “a calm niche” to work in, he says. …