Teams at Tsinghua University and TU Wien published operating thorium-229 nuclear clocks in Nature. They do not yet beat the best atomic clocks, but the researchers say the approach is now shown to work.
Teams working separately in Beijing and Vienna have built the first two operating nuclear clocks, Reuters reported on Wednesday from papers in Nature. The devices use a laser to track energy jumps inside the nucleus of thorium-229 atoms held in calcium fluoride crystals. They are not powered by fission or fusion.
Shiqian Ding of Tsinghua University, who helped lead the Beijing clock, said the teams reached operating clocks at the same time with different setups, which he took as a sign the concept is robust. Thorsten Schumm of TU Wien said his group has pursued a nuclear clock since 2008 and that physicists had wanted one for nearly 50 years.
Conventional atomic clocks time electron jumps in atoms such as cesium. A nuclear clock times protons and neutrons inside the nucleus, which is smaller and, the researchers argue, could eventually be more stable. Schumm said the clocks are still far from their target and do not yet beat the best atomic clocks, which can run for billions of years and lose or gain about a second.
He said the Vienna crystals are better and the Beijing laser is stronger, so combining the parts could improve the next device. Possible uses he named include satellite navigation, data-transfer timing, surveying and metrology. The Vienna team also used its clock in a dark-matter search that did not find dark matter but matched the precision of leading atomic clocks.
The papers are the operating demonstrations. No commercial device was announced.
People Sentiments Positive
- Shiqian Ding said the matching results show the concept does not depend on one design.
- Thorsten Schumm said a nuclear clock had been a goal for almost 50 years.
- He said the clocks are still far from their target performance.