Detecting Extragalactic Axion-like Dark Matter with Polarization Measurements of Fast Radio Bursts

Axions or axion-like particles (ALPs) are one of the promising dark matter (DM) candidates. A prevalent method to detect axion-like DM is to seek periodic oscillation in the polarization angles (PAs) of linearly polarized light emitted from astrophysical sources. In this work, we use the time-resolved polarization measurements of the hyperactive repeating fast radio burst, FRB 20220912A, detected by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) to search for extragalactic axion-like DM. Given a DM density profile of FRB 20220912A's host, we obtain upper limits on the ALP-photon coupling constant of g a γ<(3.4 times 10-11-1.9 times 10-9), GeV-1 for the ALP masses m a about (1.4 times10-21-5.2 times10-20), eV. Persistent polarimetric observations with FAST would extend the constraints to lower masses. Although the g a γ constraints derived from FRBs are less competitive than those from other methods, FRBs offer an alternative way to detect axion-like DM on extragalactic distance scales, complementary to galactic DM probes.