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Trap-induced ac Zeeman shift of the thorium-229 nuclear clock frequency



Kyle Beloy


We identify a significant threat to the accuracy of the highly anticipated nuclear clock based on $^229}$Th$^3+}$ [C. J. Campbell \it et al.}, Phys.\ Rev.\ Lett.\ 108, 120802 (2012)]. In particular, we demonstrate that the clock is susceptible to parasitic rf magnetic fields associated with the ion trapping. For typical field strengths ($\sim\!\mu$T), the ac Zeeman shift to the clock frequency may exceed the projected systematic uncertainty of the clock by orders of magnitude. By developing a theoretical treatment that incorporates the effects of a dc magnetic field, we propose a means to suppress this problematic shift. Specifically, we show that the ac Zeeman shifts to the clock levels cancel to a high degree when operating with a large dc magnetic field, restoring prospects for unprecedented clock accuracy.
Physical Review Letters


atomic clock, nuclear clock


Beloy, K. (2023), Trap-induced ac Zeeman shift of the thorium-229 nuclear clock frequency, Physical Review Letters, [online], (Accessed June 2, 2023)
Created March 8, 2023, Updated April 27, 2023