Nuclear interferometer for ultralight dark matter detection

We propose the nuclear interferometer—a single-photon interferometry experiment based upon the thorium-229 nuclear clock transition—as a novel detector for ultralight dark matter. Thanks to the enhanced sensitivity of this transition to the variation of fundamental constants, we find that possible realizations of such an experiment deploying either single ions or clouds of atoms have the potential to complement advanced very-long-baseline terrestrial clock atom interferometers in the search for ultralight dark matter with scalar couplings to photons in the future. Nuclear interferometry may also offer an unparalleled window to new physics coupling to the QCD sector via quarks or gluons, with a discovery reach that could enhance existing and proposed experiments over a range of frequencies in the direction of well-motivated parameter space.