Steven Eckel

The discovery of a permanent electric dipole moment (EDM) of a fundamental particle would prove a great discovery in modern physics, as such an EDM would violate some of the core symmetries of the fundamental forces of nature. Many models that go beyond the standard model of particle physics produce EDMs with magnitudes approaching the level detectable by the next generation of experiments. One possibility for such an experiment involves the use of a solid sample at low temperatures. In a paramagnetic material, the unpaired electrons, if they posses an EDM, can interact with the polarization of the sample and produce a magnetization that can be detected. I discuss an incarnation of such an experiment based on mixed europium-barium titanates. Such an experiment offers several advantages over other solid-state and atomic EDM searches including larger EDM induced interactions and the ability to measure without an applied electric field. This experiment has produced the world’s best limit on the electron’s EDM to date from a solid sample, at $|d_e|<6.05\times10^{-25}\ecm$ (90\% confidence limit). While this limit represents an improvement in the realm of solid-state experiments, it is not yet competitive with similar molecular and atomic experiments. However, there are many possibilities that could produce a superior solid-state experiment, and these will be discussed.