Speaker
Description
Axion-like particles offer a unified framework to address both dark matter (DM) and dark energy (DE) in cosmology. In this presentation, I will discuss recent advancements in two complementary areas. First, I will explore a quintessence axion model for dynamical dark energy, motivated by recent Baryon Acoustic Oscillation measurements from the Dark Energy Spectroscopic Instrument and Cosmic Microwave Background (CMB) observations. Our analysis identifies a preferred parameter space with a sub-Planckian axion decay constant and a relatively large axion mass, naturally avoiding the quality problem and remaining consistent with theoretical constraints. This model also provides a potential explanation for the recently reported non-zero rotation of the CMB linear polarization angle, emphasizing a broader cosmological implications. Second, I will discuss indirect detection strategies for the QCD axion as a DM candidate. Specifically, we investigate the resonant conversion of axions into photons in the presence of strong magnetic fields, such as those around neutron stars. Radio-telescope observations targeting the Andromeda galaxy have been employed to search for radio transients arising from interactions between neutron stars and dense dark matter clumps, constraining the axion-photon coupling in the mass range of 33 to 42 μeV and offering a novel observational tool to probe axion DM. Based on 2407.13060, 2504.17638 and ongoing work.
