Axion Dark Matter Detection by Superconducting Resonant Frequency Conversion

International audienceWe propose an approach to search for axion dark matter with a specially designed superconducting radio frequency cavity, targeting axions with masses m$_{a}$ ≲ 10$^{−6}$ eV. Our approach exploits axion-induced transitions between nearly degenerate resonant modes of frequency ∼ GHz. A scan over axion mass is achieved by varying the frequency splitting between the two modes. Compared to traditional approaches, this allows for parametrically enhanced signal power for axions lighter than a GHz. The projected sensitivity covers unexplored parameter space for QCD axion dark matter for 10$^{−8}$ eV ≲ m$_{a}$ ≲ 10$^{−6}$ eV and axion-like particle dark matter as light as m$_{a}$∼ 10$^{−14}$ eV