We propose an approach to search for axion dark matter with a specially designed superconducting radio frequency cavity, targeting axions with masses $m_a lesssim 10^{-6} text{ eV}$. Our approach exploits axion-induced transitions between nearly degenerate resonant modes of frequency $sim$ 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 $10^{-8} text{ eV} lesssim m_a lesssim10^{-6} text{ eV}$ and axion-like particle dark matter as light as $m_a sim 10^{-14} text{ eV}$.
Download