Condensed matter systems offer the opportunity to maximize the number of spins, probed in magnetic resonance experiments that search for physics beyond the standard model. EuCl3⋅6H2O is a promising solid-state platform for such searches. The narrow inhomogeneous linewidth of the Eu optical 7F0↔5D0 transition in this material opens the opportunity to optically pump the 153Eu nuclear spin ensemble into a single hyperfine sublevel. The closely-spaced opposite-parity nuclear energy levels, and the low-energy collective octupole mode, or a possible static octupole deformation, enhance the 153Eu nuclear Schiff moment. The optimistic estimate of the effective electric field is E∗=10MV/cm. With this estimate, the CASPEr-electric search for the gluon interaction of axion dark matter can reach QCD axion sensitivity with a 3~cm sample.
@article{arxiv.2304.12105,
title = {EuCl$_3\cdot 6$H$_2$O as the solid-state platform for searches for new P,T-odd physics},
author = {Alexander O. Sushkov},
journal= {arXiv preprint arXiv:2304.12105},
year = {2023}
}