NatureFrequency reproducibility of solid-state thorium-229 nuclear clocksTian OoiJack F. DoyleChuankun ZhangJacob S. HigginsJun YeKjeld BeeksTomas SikorskyThorsten Schumm2026-01-28Full textDOI https://doi.org/10.1038/s41586-025-09999-5