Title: The thorium-229 low-energy isomer and the nuclear clock
Authors: Beeks, Kjeld, Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Vienna, AUSTRIA, ORCID: 0000-0002-8707-6723
Sikorsky, Tomas, Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Vienna, AUSTRIA, ORCID: 0000-0003-0280-0928
Schumm, Thorsten, Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Vienna, AUSTRIA, ORCID: 0000-0002-1066-202X
Thielking, Johannes, Physikalisch-Technische Bundesanstalt (PTB), Fachbereich 4.4, Zeit und Frequenz, ORCID: 0000-0002-4511-2407
Okhapkin, Maxim V., Physikalisch-Technische Bundesanstalt (PTB), Fachbereich 4.4, Zeit und Frequenz, ORCID: 0000-0003-0420-3115

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Contributors: HostingInstitution: Physikalisch-Technische Bundesanstalt (PTB), ISNI: 0000 0001 2186 1887
Pages:18
Language:en
DOI:10.7795/120.20211006
Resource Type: Text / Article
Publisher: Physikalisch-Technische Bundesanstalt (PTB)
Rights: Download for personal/private use only, if your national copyright law allows this kind of use.
Relationships: IsVariantFormOf: DOI 10.1038/s42254-021-00286-6
Dates: Available: 2021-10-06
Created: 2021-02
File: Download File (application/pdf) 958.90 kB (981912 Bytes)
MD5 Checksum: ab433b953ff8bde95c92832ab0ec0b12
SHA256 Checksum: 5adde582f88f97effd17d7745313c3ed1bfd5a81f3e24e871a7dae10b6c92c6c
Keywords Thorium ; Th-229 ; nuclear clock ; fundamental constants
Abstract: The Th-229 nucleus is known to possess an isomeric state at an energy of about 8 eV above the ground state,
several orders of magnitude lower than typical nuclear excitation energies. This has inspired a field of
low-energy nuclear physics where nuclear transition rates will be influenced by the electron shell.
The low energy makes the Th-229 isomer accessible to resonant laser excitation. Realized with laser-cooled
trapped thorium ions or with thorium dopant ions in a transparent solid, the nuclear resonance may serve as
the reference for an optical clock of very high accuracy. Precision frequency comparisons between such a
nuclear clock and conventional atomic clocks will provide sensitivity to effects of hypothetical new physics
beyond the standard model. While laser excitation of Th-229 remains an unsolved challenge, recent experiments
have provided essential information on the transition energy and relevant nuclear properties.
Citation: Beeks, Kjeld ; Sikorsky, Tomas ; Schumm, Thorsten ; et al. The thorium-229 low-energy isomer and the nuclear clock, 2021. Physikalisch-Technische Bundesanstalt (PTB). DOI: https://doi.org/10.7795/120.20211006
Remark: Original article published in: Nature Reviews Physics 3, 238–248 (2021)