Axion detection via Topological Casimir Effect

Abstract

We propose a new table-top experimental configuration for the direct detection of dark matter QCD axions in the traditional open mass window 10^(-6)  eV ≲ m_a ≲ 10^(-2)  eV using nonperturbative effects in a system with nontrivial spatial topology. Different from most experimental setups found in literature on direct dark matter axion detection, which relies on ˙θ or ⃗∇θ, we found that our system is in principle sensitive to a static θ ≥ 10^(-14) and can also be used to set limit on the fundamental constant θ_(QED) which becomes the fundamental observable parameter of the Maxwell system if some conditions are met. Furthermore, the proposed experiments can probe entire open mass window 10^(-6)  eV ≲ m_a ≲10^(-2)  eV with the same design, which should be contrasted with conventional cavity-type experiments being sensitive to a specific axion mass. Connection with Witten effect when the induced electric charge e′ is proportional to θ and the magnetic monopole becomes the dyon with nonvanishing e′ = -eθ/2π is also discussed.