The Upcoming JILA Gen. III eEDM Experiment

ThF$^+$ is the champion for the third-generation (Gen. III) measurement of the electric dipole moment of the electron (eEDM) at JILA. Compared to the current HfF$^+$ eEDM experiment, ThF$^+$ has several advantages: (i) the eEDM-sensitive state ($^3\Delta_1$) is the ground state [1,2], with a projected coherence time on the order of a few minutes; and (ii) its effective electric field (38 GV/cm) is 50\% larger than that of HfF$^+$ [3], which promises a direct increase of the eEDM sensitivity. Herein, we present the final spectroscopic work on the $^3\Delta_1$ state, and discuss multiplexing strategies to increase our effective count rate in Gen. III by two orders of magnitude over the Gen. II experiment.\\ \\ 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. Skripnikov, L. V., and A. V. Titov. ``Theoretical study of ThF+ in the search for T, P-violation effects: Effective state of a Th atom in ThF+ and ThO compounds.'' Physical Review A 91.4 (2015): 042504.