# Axion Dark Matter Search with Interferometric Gravitational Wave Detectors

## TL;DR

This paper proposes a novel method using interferometric gravitational wave detectors to search for axion dark matter by measuring phase differences in photons, achieving high sensitivity across a range of axion masses without affecting gravitational wave detection.

## Contribution

It introduces a new scheme to detect axion-photon coupling using existing gravitational wave detectors, enhancing sensitivity to axion dark matter over a broad mass range.

## Key findings

- Potential sensitivity to axion-photon coupling reaches 8×10⁻¹³ GeV⁻¹ at specific masses.
- Sensitivity remains high across three orders of magnitude in axion mass.
- Achieves detection sensitivity without compromising gravitational wave measurements.

## Abstract

Axion dark matter differentiates the phase velocities of the circular-polarized photons. In this Letter, a scheme to measure the phase difference by using a linear optical cavity is proposed. If the scheme is applied to the Fabry-P\'erot arm of Advanced LIGO-like (Cosmic-Explorer-like) gravitational wave detector, the potential sensitivity to the axion-photon coupling constant, $g_{\text{a}\gamma}$, reaches $g_{\text{a}\gamma} \simeq 8\times10^{-13}$ GeV$^{-1}\, (4 \times 10^{-14}$ GeV$^{-1})$ at the axion mass $m \simeq 3\times 10^{-13}$ eV ($2\times10^{-15}$ eV) and remains at around this sensitivity for 3 orders of magnitude in mass. Furthermore, its sensitivity has a sharp peak reaching $g_{\text{a}\gamma} \simeq 10^{-14}$ GeV$^{-1}$ $(8\times10^{-17}$ GeV$^{-1})$ at $m = 1.563\times10^{-10}$ eV ($1.563\times10^{-11}$ eV). This sensitivity can be achieved without loosing any sensitivity to gravitational waves.