AIP summer meeting 2025

Nuclear Clock and the Search for New Physics

4 Dec 2025, 16:10

30m

Hope Theatre (Building 40)

Invited/Keynote talk Atomic and Molecular Physics Atomic and Molecular Physics

Speaker

Victor Flambaum (University of New South Wales)

Description

Nuclear Clock and the Search for New Physics
The isomeric transition in 229Th - recently laser-excited by multiple groups [1] - opens a path to a nuclear clock with accuracy competitive with, and potentially exceeding, the best optical atomic clocks. Because the nucleus is well shielded from environmental perturbations, systematic shifts can be intrinsically small; however, the surrounding electrons strongly mediate excitation and decay via the electronic-bridge mechanism and can modify both transition frequency and lifetime by orders of magnitude [2]. Electron-induced shifts of the nuclear transition must therefore be quantified [3]. A “stretched-state” scheme suppresses leading-order electron–nucleus entanglement and mitigates key systematic effects [4].
The 229Th transition is exceptionally sensitive to physics beyond the Standard Model: spatial/temporal variation of fundamental constants (α, quark masses, Λ_QCD) [5], ultralight dark-matter couplings to gluons and nucleons [6], and violations of Lorentz invariance and Einstein’s equivalence principle [7]. Four orders enhancement factors relative to electronic transitions, together with frequency-ratio networks linking nuclear and atomic references, enable stringent, model-aware constraints.
[1]C.Zhang et al.,Nature 633,63(2024).
[2]S.G.Porsev,V.V.Flambaum,E.Peik,C.Tamm,Phys.Rev.Lett.105,182501(2010); S.G.Porsev,V.V.Flambaum,Phys. Rev.A81, 042516 (2010): V.A.Dzuba,V.V.Flambaum, Phys.Rev.A111,L041103 (2025);A111, 053109 (2025);A112,023103 (2025).
[3]V.A.Dzuba, V.V.Flambaum, Phys.Rev.Lett. 131, 263002 (2023).
[4] C. J. Campbell, A. G.Radnaev, A. Kuzmich, V. A. Dzuba, V. V. Flambaum, and A. Derevianko, Phys.Rev.Lett.108, 120802 (2012).
[5] V. V. Flambaum, Phys. Rev. Lett. 97, 092502 (2006). ] E. Litvinova, H. Feldmeier, J. Dobaczewski & V. V. Flambaum, Phys. Rev. C 79, 064303 (2009).J. C. Berengut, V. A. Dzuba, V. V. Flambaum, S. G. Porsev, Phys. Rev. Lett. 102, 210801 (2009). P. Fadeev, J. C. Berengut, V. V. Flambaum, Phys. Rev. A 102, 052833 (2020). V. V. Flambaum, A. J. Mansour, arxiv 2508.07266
[6] Y. V. Stadnik, V. V. Flambaum, Phys. Rev. Lett. 115, 201301 (2015).
[7] V. V. Flambaum, Phys. Rev. Lett. 117, 072501 (2016).