# Tunable axion plasma haloscopes

## TL;DR

This paper introduces a novel approach to detect dark matter axions using tunable cryogenic plasmas, enabling resonant conversion by matching axion mass to plasma frequency, which is independent of device size.

## Contribution

It proposes using wire metamaterials as tunable plasma media for axion detection, offering a scalable and potentially more sensitive alternative to existing haloscope methods.

## Key findings

- Potential to detect axions in the 35-400 μeV mass range
- Large conversion volumes due to plasma frequency independence from size
- Competitive sensitivity estimates for realistic experimental setups

## Abstract

We propose a new strategy to search for dark matter axions using tunable cryogenic plasmas. Unlike current experiments, which repair the mismatch between axion and photon masses by breaking translational invariance (cavity and dielectric haloscopes), a plasma haloscope enables resonant conversion by matching the axion mass to a plasma frequency. A key advantage is that the plasma frequency is unrelated to the physical size of the device, allowing large conversion volumes. We identify wire metamaterials as a promising candidate plasma, wherein the plasma frequency can be tuned by varying the interwire spacing. For realistic experimental sizes we estimate competitive sensitivity for axion masses $35-400\,\mu$eV, at least.