New Experimental Limit on the Electric Dipole Moment of the Electron in a Paramagnetic Insulator

TL;DR

This paper presents a new experimental limit on the electron's electric dipole moment using a solid-state approach with gadolinium gallium garnet, achieving improved sensitivity and background suppression.

Contribution

It introduces a novel solid-state experimental technique with enhanced background suppression to set a more stringent limit on the electron EDM.

Findings

First limit on the eEDM using GGG with value (-5.57 ± 7.98 ± 0.12)×10^{-25} e·cm.

Achieved background suppression allowing measurements at the statistical uncertainty level.

Demonstrated the feasibility of solid-state methods for fundamental particle property measurements.

Abstract

We report results of an experimental search for the intrinsic Electric Dipole Moment (EDM) of the electron using a solid-state technique. The experiment employs a paramagnetic, insulating gadolinium gallium garnet (GGG) that has a large magnetic response at low temperatures. The presence of the eEDM would lead to a small but non-zero magnetization as the GGG sample is subject to a strong electric field. We search for the resulting Stark-induced magnetization with a sensitive magnetometer. Recent progress on the suppression of several sources of background allows the experiment to run free of spurious signals at the level of the statistical uncertainties. We report our first limit on the eEDM of $(-5.57 \pm 7.98 \pm 0.12)\times$10$^{-25}$e$\cdot$cm with 5 days of data averaging.