Nuclear clock

A nuclear clock is a notional clock that would use the frequency of a nuclear transition as its reference frequency, in the same manner as an atomic clock uses the frequency of an electronic transition in an atom's shell. Such a clock is expected to be more accurate than the best current atomic clocks,[1] with a fractional instability at the 10−19 level.[2]

The thorium-229m transition

Main article: Thorium-229m

The only nuclear transition suitable as a reference frequency is the gamma decay of thorium-229m, a nuclear isomer of thorium-229 and the lowest-energy nuclear isomer known. The transition is expected to be in the vacuum ultraviolet, which would make it accessible to laser excitation.

In 2016, the first direct detection of the isomeric transition has constrained its energy to be between 6.3 and 18.3 eV. [3][4]

References

  1. ↑ "Physics: From the atomic to the nuclear clock". Ludwig-Maximilians-Universität München. 6 May 2016. Retrieved 22 August 2016.
  2. ↑ G. A. Kazakov; A. N. Litvinov; V. I. Romanenko; L. P. Yatsenko; A. V. Romanenko; M. Schreitl; G. Winkler; T. Schumm (2 Oct 2012). "Performance of a 229 Thorium solid-state nuclear clock". arXiv:1204.3268v3Freely accessible [physics.atom-ph].
  3. ↑ von der Wense, Lars; Seiferle, Benedict; Laatiaoui, Mustapha; Neumayr, Jürgen B.; Maier, Hans-Jörg; Wirth, Hans-Friedrich; Mokry, Christoph; Runke, Jörg; Eberhardt, Klaus; Düllmann, Christoph E.; Trautmann, Norbert G.; Thirolf, Peter G. (5 May 2016). "Direct detection of the 229Th nuclear clock transition". Nature. 533 (7601): 47–51. doi:10.1038/nature17669.
  4. ↑ "Results on 229mThorium published in "Nature"" (Press release). Ludwig Maximilian University of Munich. 2016-05-06.
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