Axion Wind Detection with the Homogeneous Precession Domain of Superfluid Helium-3

Phys Rev Lett. 2022 Nov 18;129(21):211801. doi: 10.1103/PhysRevLett.129.211801.

Abstract

Axions and axionlike particles may couple to nuclear spins like a weak oscillating effective magnetic field, the "axion wind." Existing proposals for detecting the axion wind sourced by dark matter exploit analogies to nuclear magnetic resonance (NMR) and aim to detect the small transverse field generated when the axion wind resonantly tips the precessing spins in a polarized sample of material. We describe a new proposal using the homogeneous precession domain of superfluid ^{3}He as the detection medium, where the effect of the axion wind is a small shift in the precession frequency of a large-amplitude NMR signal. We argue that this setup can provide broadband detection of multiple axion masses simultaneously and has competitive sensitivity to other axion wind experiments such as CASPEr-Wind at masses below 10^{-7} eV by exploiting precision frequency metrology in the readout stage.