The Buildup to JILA Gen. III eEDM Experiment

The third-generation (Gen. III) apparatus for the measurement of the electric dipole moment of the electron (eEDM) at JILA utilizes ThF⁺. ThF⁺ has several potential advantages over HfF⁺ used in the second-generation experiment: (i) the eEDM-sensitive state (³Δ₁) has a longer coherence time of about 20 seconds suggested by [1,2]; (ii) ThF⁺’s effective electric field (35 GV/cm) is 50% larger than that of HfF⁺ [3], which promises a direct increase of the eEDM sensitivity. To fully exploit the advantage of ThF⁺’s long coherence time while enhancing the measurement count rate, we introduce a new multiplexing strategy, which would continuously load and read out ThF⁺. With this strategy, we expect Gen. III to reach a limit of |d_e| < 10^-31 e·cm. However, the price for achieving a long coherence time and the multiplexing strategy is highly homogeneous electromagnetic field during Ramsey oscillation and complicated ion trap structure. We will present the current status of the field simulation and the ion trap design.

[1] Gresh, Daniel N., et al. “Broadband velocity modulation spectroscopy of ThF⁺ for use in a measurement of the electron electric dipole moment.” Journal of Molecular Spectroscopy 319 (2016): 1-9.

[2] Zhou, Yan, et al. “Visible and ultraviolet laser spectroscopy of ThF.” arXiv:1901.06084 (2019)

[3] Denis, Malika, et al. "Theoretical study on ThF+, a prospective system in search of time-reversal violation." New Journal of Physics 17.4 (2015): 043005.