Axion Dark Matter Detection by Superconducting Resonant Frequency Conversion

Abstract

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 $10^{-8}\text{ eV}\lesssim m_a\lesssim 10^{-6}\text{ eV}$ and axion-like particle dark matter as light as $m_a\sim 10^{-14}\text{ eV}$.

30 pages, 7 figures