The JILA Gen III Experiment on electron's Electric Dipole Moment (eEDM): Achieving long coherence time

Using molecular ions HfF⁺, the second generation of the JILA eEDM experiment recently reported the most precise measurement of the eEDM, d_e = (-1.3±2.0_stat±0.6_syst) x 10^-30 e cm [1,2]. To improve upon this precision, the third generation of the experiment utilizes ThF⁺ whose eEDM sensitive state promises coherence time of ~20 s [3,4,5]. To take full advantage of the long coherence time, the third-generation experiment will include a “conveyor belt” of 25 consecutive ion traps, named the Bucket Brigade, which will continuously load and read out ThF⁺, allowing for an increased repetition rate without compromising long interrogation times. We are currently studying a prototype of the Bucket Brigade at a reduced scale. We will present our progress on the prototype towards the realization of long coherence time, including cryogenics designs, field homogeneity requirements, and improved state detection techniques.





[1] Roussy, Tanya S., et al. Science 381, 46-50 (2023).

[2] Caldwell, Luke, et al. Physical Review A 108 (2023): 012804

[3] Gresh, Daniel N., et al. Journal of Molecular Spectroscopy 319 (2016): 1-9.

[4] Zhou, Yan et al. J. Mol. Spec. 358, (2019) 1-16

[5] Ng, Kia Boon et al. Physical Review A 105 (2022): 022823