Searching for Axion Dark Matter in Atoms: Oscillating Electric Dipole Moments and Spin-Precession Effects

TL;DR

This paper proposes a novel method to detect axion dark matter by observing oscillating electric dipole moments and spin-precession effects in atoms and molecules, which are induced by axion interactions.

Contribution

It introduces a new experimental approach to search for axion dark matter through atomic and molecular electric dipole moments and spin-precession effects caused by axion couplings.

Findings

Theoretical framework for axion-induced electric dipole moments in atoms.

Analysis of spin-precession effects as a detection method.

Identification of multiple axion-fermion coupling channels.

Abstract

We propose to search for axion dark matter via the oscillating electric dipole moments that axions induce in atoms and molecules. These moments are produced through the intrinsic oscillating electric dipole moments of nucleons and through the $P,T$-violating nucleon-nucleon interaction mediated by pion exchange, both of which arise due to the axion-gluon coupling, and also directly through the axion-electron interaction. Axion dark matter may also be sought for through the spin-precession effects that axions produce by directly coupling to fermion spins.