Work

The Atacama Cosmology Telescope: DR6 Constraints on Isotropic Time-Dependent Cosmic Birefringence from Axion-like Particles

Year: 2026

Type: preprint

Abstract: Axion-like particles (ALPs) with sufficiently low masses are dark matter candidates because they could account for much or all of the observed dark matter energy density and help explain observations of galactic substructure. Such pseudoscalar fields could couple to photons, causing a time-dependent rotation of the polarization of the light with an oscillation frequency equal to the ALP mass. We use measurements of the polarization of the cosmic microwave background (CMB) by the Atacama Cosmology Telescope (ACT) between 2017 and 2022 to search for this effect using an EB power spectrum estimator. By probing oscillation periods from days to years, the data constrain the coupling between ALPs and photons for ALP masses between $2.5\times 10^{-23}$ eV and $4.8\times 10^{-20}$ eV. We find no evidence for such a signal and set a 95% upper bound on the axion-photon coupling constant, $g_{ϕγ} < 1.1\times10^{-11}\left({m_ϕ}/{10^{-21}\,\mathrm{eV}}\right)\,\mathrm{GeV}^{-1} .$ This limit assumes that ALPs make up all of the dark matter and that the ALP field amplitude is stochastically distributed, which leads to more conservative bounds than the deterministic-field assumption used in some previous CMB polarization analyses. Among searches for ALP-photon coupling using CMB polarization, we set the strongest bounds to date under the stochastic-field assumption. This work develops a methodology to analyze over 10,000 time-sliced "depth-1" polarization maps from ACT, a data product that will be standard for time-domain astrophysics with the Simons Observatory, enabling searches with a higher sensitivity and observing span.

Source: arXiv (Cornell University)

DOI: 10.48550/arxiv.2610.19049

Authors: Huber, Zachary B., Yang, Huajian, Choi, Steve K., Calabrese, Erminia, Gluscevic, Vera, Naess, Sigurd, Niemack, Michael D., Page, Lyman A., van Engelen, Alexander, Wollack, Edward J.

Institutions: Cornell University, Cardiff University, University of Southern California, University of Oslo, Goddard Space Flight Center

Language: English

Topic: Dark Matter and Cosmic Phenomena

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, National Aeronautics and Space Administration, Princeton University, University of Pennsylvania, National Energy Research Scientific Computing Center, Agencia Nacional de Investigación y Desarrollo, National Institute of Standards and Technology

Awards: BROAD BANDWIDTH METAMATERIAL ANTIREFLECTION COATINGS FOR MEASUREMENT OF THE COSMIC MICROWAVE BACKGROUND WE PROPOSE TO DEVELOP BROAD-BAND METAMATERIAL, THIS PROPOSAL SEEKS SUPPORT FOR THE DEVELOPMENT OF MILLIMETER-WAVELENGTH MULTICHROIC POLARIMETERS OPTIMIZED FOR DETECTING COSMIC MICROWAVE BACKGROUND, Gravitational Physics from the Cosmic Microwave Background, Gravitational Physics from the Cosmic Microwave Background, Collaborative Research with the Atacama Cosmology Telescope (ACT): Probing Fundamental Physics Through Observations of Cosmic Structure, Advanced ACTPol, Gravitational Physics from the Cosmic Microwave Background, ACTPol: The Atacama Cosmology Telescope with Polarization

OpenAlex ID: W7222153836

Cites: 44

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Related to: 10