# Axion detection via Topological Casimir Effect

## TL;DR

This paper proposes a novel tabletop experiment to detect dark matter axions in the 10^{-6} to 10^{-2} eV range by exploiting topological effects in a system sensitive to static theta, differing from traditional methods.

## Contribution

It introduces a new experimental setup sensitive to static theta, enabling direct axion detection and setting limits on the QED theta parameter, with connections to the Witten effect.

## Key findings

- System sensitive to static theta ≥ 10^{-14}
- Potential to set limits on QED theta parameter
- Connection established with the Witten effect

## Abstract

We propose a new table-top experimental configuration for the direct detection of dark matter axions with mass in the $(10^{-6} \rm eV - 10^{-2} \rm eV)$ range using non-perturbative effects in a system with non-trivial spatial topology. Different from most experimental setups found in literature on direct dark matter axion detection, which relies on $\dot{\theta}$ or $\vec{\nabla}\theta$, we found that our system is in principle sensitive to a static $\theta\geq 10^{-14}$ and can also be used to set limit on the fundamental constant $\theta_{\rm QED}$ which becomes the fundamental observable parameter of the Maxwell system if some conditions are met. Connection with Witten effect when the induced electric charge $e'$ is proportional to $\theta$ and the magnetic monopole becomes the dyon with non-vanishing $e'=-e \frac{\theta}{2\pi}$ is also discussed.