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Development of a solid-state <sup>229</sup>Th nuclear clock

ORAL

Abstract

The 229mTh isomeric nuclear transition, with an energy of 8.4 eV (λ=148 nm), is a prime candidate for a nuclear optical frequency reference. The transition is expected to have a high quality factor and enhanced sensitivity for ultra-light dark matter searches. Last year, our team achieved quantum-state-resolved laser spectroscopy of the nucleus in a 229Th:CaF2 crystal using a vacuum-ultraviolet frequency comb.

To build a clock, state-dependent systematic shifts of the nuclear transition frequency must be well-characterized and understood. We present our study of the temperature dependence of the transition frequency and the 229Th concentration dependence of the transition linewidth. We also present our ongoing ‘time record’ of the nuclear transition frequency referenced to the JILA Sr atomic clock, providing a unique monitor for temporal variations in fundamental constants.

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Publication: 1. Zhang, C. et al. Frequency ratio of the 229mTh nuclear isomeric transition and the 87Sr atomic clock. Nature 633, 63–70 (2024).<br>2. Higgins, J. S. et al. Temperature sensitivity of a Thorium-229 solid-state nuclear clock. (accepted, PRL)

Presenters

  • Tian Ooi

    University of Colorado, Boulder

Authors

  • Tian Ooi

    University of Colorado, Boulder

  • John F Doyle

    JILA

  • Chuankun Zhang

    University of Colorado, Boulder

  • Jacob S Higgins

    JILA

  • Jun Ye

    JILA, National Institute of Standards and Technology and University of Colorado and Department of Physics, University of Colorado, Boulder, University of Colorado, Boulder