Probing fast oscillating scalar dark matter with atoms and molecules

Light scalar dark matter (DM) with scalar couplings to matter is expected within several scenarios to induce variations in the fundamental constants of nature. Such variations can be searched for, among other ways, via atomic spectroscopy. Sensitive atomic observables arise primarily due to possible changes in the fine-structure constant or the electron mass. Most of the searches to date have focused on slow variations of the constants (i.e. modulation frequencies <1 Hz). In a recent experiment (2019 Phys. Rev. Lett. 123 141102) called weekend relaxion-search laboratory (WReSL), we reported on a direct search for rapid variations in the radio-frequency band. Such a search is particularly motivated within a class of relaxion DM models. We discuss the WReSL experiment, report on progress toward improved measurements of rapid fundamental constant variations, and discuss the planned extension of the work to molecules, in which rapid variations of the nuclear mass can be sensitively searched for.

Automated summary

In this study, the potential variations in fundamental constants of nature induced by light scalar dark matter with scalar couplings to matter is discussed. The focus is on rapid changes, with recent experiments like WReSL reporting on direct searches in the radio-frequency band. Future plans include extending the work to molecules for sensitive searches of rapid variations in nuclear mass.