Submission + - Get ready for Nuclear Clocks (arxiv.org)
From the paper: "Optical atomic clocks use electronic energy levels to precisely keep track of time. A clock based on nuclear energy levels promises a next-generation platform for precision metrology and fundamental physics studies."..."These results mark the start of nuclear-based solid-state optical clock and demonstrate the first comparison of nuclear and atomic clocks for fundamental physics studies. This work represents a confluence of precision metrology, ultrafast strong field physics, nuclear physics, and fundamental physics."
Disclaimer: I do IT work for JILA, the CU Boulder/NIST department at which Jun and his group do their work.