Frequency ratio of the229mTh nuclear isomeric transition and the87Sr atomic clock
- PMID:39232152
- DOI: 10.1038/s41586-024-07839-6
Frequency ratio of the229mTh nuclear isomeric transition and the87Sr atomic clock
Abstract
Optical atomic clocks1,2 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. Thorium-229 nuclei exhibit a uniquely low-energy nuclear transition within reach of state-of-the-art vacuum ultraviolet (VUV) laser light sources and have, therefore, been proposed for construction of a nuclear clock3,4. However, quantum-state-resolved spectroscopy of the229mTh isomer to determine the underlying nuclear structure and establish a direct frequency connection with existing atomic clocks has yet to be performed. Here, we use a VUV frequency comb to directly excite the narrow229Th nuclear clock transition in a solid-state CaF2 host material and determine the absolute transition frequency. We stabilize the fundamental frequency comb to the JILA87Sr clock2 and coherently upconvert the fundamental to its seventh harmonic in the VUV range by using a femtosecond enhancement cavity. This VUV comb establishes a frequency link between nuclear and electronic energy levels and allows us to directly measure the frequency ratio of the229Th nuclear clock transition and the87Sr atomic clock. We also precisely measure the nuclear quadrupole splittings and extract intrinsic properties of the isomer. These results mark the start of nuclear-based solid-state optical clocks and demonstrate the first comparison, to our knowledge, 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.
© 2024. The Author(s), under exclusive licence to Springer Nature Limited.
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References
- Ludlow, A. D., Boyd, M. M., Ye, J., Peik, E. & Schmidt, P. O. Optical atomic clocks. Rev. Mod. Phys. 87, 637–701 (2015). - DOI
- Aeppli, A., Kim, K., Warfield, W., Safronova, M. S. & Ye, J. Clock with 8 × 10−19 systematic uncertainty. Phys. Rev. Lett. 133, 023401 (2024).
- Peik, E. & Tamm, C. Nuclear laser spectroscopy of the 3.5 eV transition in Th-229. EPL – Europhys. Lett. 61, 181 (2003). - DOI
- Tkalya, E. V., Varlamov, V. O., Lomonosov, V. V. & Nikulin, S. A. Processes of the nuclear isomer229mTh(3/2+, 3.5 ± 1.0 eV) resonant excitation by optical photons. Phys. Scr. 53, 296 (1996). - DOI
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