Grau, Matt

Date: Friday, June 19, 2015
Time: 14:00
Place: ETH Zurich, Hönggerberg, HPF G 6
Host: Jonathan Home

A precision measurement of the electron's electric dipole moment using trapped molecular ions

Matt Grau
JILA, Boulder, CO, USA

An electron electric dipole moment (eEDM) directly violates time-reversal symmetry, which has implications for physics beyond the Standard Model. An experiment using trapped molecular ions offers high sensitivity because of the large effective electric fields and long coherence times that are possible. Here we demonstrate precision spectroscopy on many trapped HfF⁺ ions in a radiofrequency quadrupole trap with rotating frame bias fields. We perform Ramsey spectroscopy between spin states of the metastable  ³𝚫₁ level with a coherence time exceeding 1 second. The Fourier-limited linewidth of 160 mHz is, to our knowledge, the narrowest line observed in a molecular system. In contrast to preceding eEDM experiments using molecular beams, we will be sensitive to a different class of systematic effects. We will discuss systematic errors arising from trapping and polarizing electric fields, magnetic field gradients, and motional effects such as geometric phases, and demonstrate a preliminary eEDM measurement with a statistical sensitivity of 3x10^-28 e·cm in 200 hours.