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Register a new userA precision measurement of the electrons electric dipole moment using trapped molecular ions
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We describe the first precision measurement of the electrons electric dipole moment (eEDM, $d_e$) using trapped molecular ions, demonstrating the application of spin interrogation times over 700 ms to achieve high sensitivity and stringent rejection of systematic errors. Through electron spin resonance spectroscopy on $^{180}{rm Hf}^{19}{rm F}^{+}$ in its metastable $^{3}Delta_{1}$ electronic state, we obtain $d_e = (0.9 pm 7.7_{rm stat} pm 1.7_{rm syst}) times 10^{-29},e,{rm cm}$, resulting in an upper bound of $|d_e| < 1.3 times 10^{-28},e,{rm cm}$ (90% confidence). Our result provides independent confirmation of the current upper bound of $|d_e| < 9.3 times 10^{-29},e,{rm cm}$ [J. Baron $textit{et al.}$, Science $textbf{343}$, 269 (2014)], and offers the potential to improve on this limit in the near future.
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The electric dipole moment of the electron (eEDM) can be measured with high precision using heavy polar molecules. In this paper, we report on a series of new techniques that have improved the statistical sensitivity of the YbF eEDM experiment. We increase the number of molecules participating in the experiment by an order of magnitude using a carefully designed optical pumping scheme. We also increase the detection efficiency of these molecules by another order of magnitude using an optical cycling scheme. In addition, we show how to destabilise dark states and reduce backgrounds that otherwise limit the efficiency of these techniques. Together, these improvements allow us to demonstrate a statistical sensitivity of $1.8 times 10^{-28}$ e cm after one day of measurement, which is 1.2 times the shot-noise limit. The techniques presented here are applicable to other high-precision measurements using molecules.
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We propose a novel approach in a search for the neutron electric dipole moment (EDM) by taking advantage of signal amplification in a weak measurement, known as weak value amplification. Considering an analogy to the weak measurement that can measure the spin magnetic moment interaction, we examine an experimental setup with a polarized neutron beam through an external electric field with spatial gradient, where the signal is sensitive to the EDM interaction. In particular, a dedicated analysis of effects from impurities in pre- and post-selections is performed. We show that the weak value amplification occurs where the signal is enhanced by up to two orders of magnitude, and demonstrate a potential sensitivity of the proposed setup to the neutron EDM.
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