Countdown to a nuclear clock

In September, the group of Jun Ye from JILA in Boulder, Colorado published exciting news about the Thorium-229m nuclear isomeric transition in Nature. ^229mTh nuclei are due to the uniquely low-lying energy transition interesting for the implementation of a nuclear clock. However, driving this transition is challenging. The group of Jun Ye they built a VUV frequency comb to excite the nuclear transition. This frequency comb enabled the experimentalists to synchronize the ²²⁹Th nuclear clock transition with an optical clock based on ⁸⁷Sr atoms. Since the implementation of a nuclear clock is of great relevance for metrology purposes, these results are an important step to answer questions like whether nuclear and electromagnetic forces are constant in time.
Due to its significance, this publication adorns the cover of the Nature magazine. Furthermore, Adriana was invited to write a "News and Views" editorial article together with José R. Crespo López-Urrutia, explaining the results for a wide audience.