682254 event 1746536463 1746536579 <![CDATA[A solid-state nuclear clock using a VUV frequency comb]]> Chuankun Zhang is a graduate student in the Ye group at JILA, NIST, and the University of Colorado Boulder, where he is working to develop an optical clock based on the thorium-229 nuclear transition. Together with his colleagues, he has contributed to multiple aspects of this effort, including generating and stabilizing a vacuum-ultraviolet frequency comb, fabricating thorium fluoride thin films, and demonstrating quantum state-resolved nuclear laser spectroscopy. Their ongoing work focuses on characterizing and improving the performance of this novel nuclear quantum platform for timekeeping.

]]> Leveraging the exceptional environmental insensitivity of nuclear transitions, we demonstrate a solid-state clock with more than 1015 thorium-229 nuclei hosted in a 1 mm3 crystal, unlocking access to quantum devices with unprecedented large numbers of coherently controlled quantum emitters.

A major technological obstacle in realizing nuclear clocks is the lack of coherent laser light sources at nuclear transition wavelengths. Using a frequency comb laser in the vacuum-ultraviolet (VUV), we resolve the individual nuclear quantum states of the low-energy thorium-229 nuclear transition in a CaF2 crystal host and precisely determine their frequencies, referenced to the JILA strontium-87 optical lattice clock. We systematically characterize the state-dependent clock frequency reproducibility with respect to temperature, doping concentration and time.

This nuclear clock promises a scalable and portable platform for quantum science and metrology. Nuclear-atomic clock comparisons will also enable stringent tests for new physics beyond the Standard Model.

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