Searching for dark matter with a spin-based interferometer.

Gavilan-Martin, Daniel; Łukasiewicz, Grzegorz; Padniuk, Mikhail; Klinger, Emmanuel; Smolis, Magdalena; Figueroa, Nataniel L; Jackson Kimball, Derek F; Sushkov, Alexander O et al. · Nat Commun · 2025

basic_science · Level V

Where this comes from

Abstract

Axion-like particles (ALPs) arise from well-motivated extensions to the Standard Model and could account for dark matter. ALP dark matter would manifest as a field oscillating at an (as of yet) unknown frequency. The frequency depends linearly on the ALP mass and plausibly ranges from 10<sup>-22</sup> to 10 eV/c<sup>2</sup>. This motivates broadband search approaches. We report on a direct search for ALP dark matter with an interferometer composed of two atomic K-Rb-<sup>3</sup>He comagnetometers, one situated in Mainz, Germany, and the other in Kraków, Poland. We leverage the anticipated spatio-temporal coherence properties of the ALP field and probe all ALP-gradient-spin interactions covering a mass range of nine orders of magnitude. No significant evidence of an ALP signal is found. We thus place new upper limits on the ALP-neutron, ALP-proton and ALP-electron couplings reaching below g<sub>aNN</sub> < 10<sup>-9</sup> GeV<sup>-1</sup>, g<sub>aPP</sub> < 10<sup>-7</sup> GeV<sup>-1</sup> and g<sub>aee</sub> < 10<sup>-6</sup> GeV<sup>-1</sup>, respectively. These limits improve upon previous laboratory constraints for neutron and proton couplings by up to three orders of magnitude.