Cosmic Birefringence and Axiogenesis
Abstract
Recent analyses of Planck and ACT CMB data report a 2−4σ hint of isotropic cosmic birefringence (β≈ 0.3∘), corresponding to a parity-violating rotation of polarization planes that points to potential new physics. We show that both the hint of cosmic birefringence and the observed baryon asymmetry can be simultaneously explained by the rotation of an axion-like field. The minimal setup predicts a positive birefringence angle, consistent with the CMB hint, and matter and kination domination ending around a temperature of 𝒪(3−50) MeV, making the model falsifiable by astrophysical probes and potentially giving rise to characteristic gravitational-wave signals. We also introduce a mechanism that can exponentially enhance the angular momentum of the rotation generated by the Affleck-Dine mechanism.
Related
- De-lensing cosmic birefringence with joint reconstruction
- Cosmic birefringence tomography with radio galaxies I: Testing birefringence solutions to the CMB-BAO tension
- Cosmic Birefringence from Large Lepton Asymmetry
- Cosmic birefringence from a stiff axion field and its cosmological implications
- Alleviating CMB-BAO tension with a large cosmic birefringence angle during reionization induced by energy injection to axion-like particles
BibTeX
@misc{co2026cosmic,
title = {{Cosmic Birefringence and Axiogenesis}},
author = {Raymond T. Co and Lawrence J. Hall and Keisuke Harigaya and Taegyu Lee},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.25202},
eprint = {2609.25202},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.25202},
}
RIS
TY - UNPB
TI - Cosmic Birefringence and Axiogenesis
AU - Raymond T. Co
AU - Lawrence J. Hall
AU - Keisuke Harigaya
AU - Taegyu Lee
PY - 2026
DA - 2026/09/21
PB - arXiv
DO - 10.48550/arxiv.2609.25202
UR - https://arxiv.org/abs/2609.25202
AB - Recent analyses of Planck and ACT CMB data report a 2−4σ hint of isotropic cosmic birefringence (β≈ 0.3^∘), corresponding to a parity-violating rotation of polarization planes that points to potential new physics. We show that both the hint of cosmic birefringence and the observed baryon asymmetry can be simultaneously explained by the rotation of an axion-like field. The minimal setup predicts a positive birefringence angle, consistent with the CMB hint, and matter and kination domination ending around a temperature of 𝒪(3−50) MeV, making the model falsifiable by astrophysical probes and potentially giving rise to characteristic gravitational-wave signals. We also introduce a mechanism that can exponentially enhance the angular momentum of the rotation generated by the Affleck-Dine mechanism.
ER -