Searching for axion-like particles with space-based optical lattice clock networks

Abstract

Axion like particles (ALPs) are particularly well motivated candidates for dark matter, and physics beyond the Standard Model more generally. However, direct detection remains extremely challenging due to the weakness of their interactions. In this work, we propose to employ space-based optical lattice clock networks (SOLCN), originally targeted to probe the stochastic gravitational wave background (SGWB), to detect axion dark matter through cosmic birefringence via minor modifications to their laser links. Searching for cross-correlated signals then provides significant sensitivity to low mass ALPs as a result of their large correlation lengths. In this work we focus on ALPs in the mass range $10^{-18.55}\text{eV}-10^{-14}\text{eV}$, For ALPs mass region $10^{-18}-10^{-14}\text{eV}$, finding that we can probe down to $g_{aγ}\geq 10^{-12}\,\text{GeV}^{-1}$. Moreover, we find that the SOLCN sensitivity to the ALP-photon coupling depends crucially on the frequency of the network link. With an $8$ GHz frequency link, we then have the potential to reach $g_{aγ}\geq10^{-16}\,\text{GeV}^{-1}$ in this region.