Distinguishing the origin of cosmic birefringence: dark energy, dark matter, and neutrino asymmetry
Abstract
Cosmic birefringence, the isotropic rotation of the plane of linear polarization of photons from sources at cosmological distances, can be generated by different parity-violating mechanisms. While the net rotation angle of a single polarized source carries little information about its physical origin, sources at various redshifts z can be used to distinguish between different origins. Parity-sensitive correlations of the E- and B-mode polarization fields of the cosmic microwave background measured on large and small angular scales probe sources at z≃ 10 and $1100$, respectively. Thus, the detailed shape of the EB power spectrum is sensitive to the redshift evolution of the birefringence source. In this paper, we calculate the EB power spectrum due to a neutrino-asymmetry current, and compare it to axion dark energy and dark matter using a common Chern--Simons framework. We find that the EB power spectrum due to a neutrino asymmetry is suppressed at low multipoles, ℓ≲ 20, similar to the dark matter case. This can be clearly distinguished from the dark energy case, which has no such suppression. Large-scale polarization measurements, including \textit{LiteBIRD}, can therefore distinguish late-time dark energy birefringence from that generated at higher redshifts by axion dark matter or neutrino asymmetry. We also find that the evolution of the neutrino density during recombination alters the shape of the EB power spectrum at high multipoles. This signature can be used to distinguish between the neutrino and axion dark matter interpretations, using ground-based experiments such as the Simons Observatory.
Related
- Cosmic Birefringence from Large Lepton Asymmetry
- De-lensing cosmic birefringence with joint reconstruction
- Can cosmic neutrinos induce a cosmic birefringence signal?
- Cosmic Birefringence and Axiogenesis
- Cosmic birefringence tomography with radio galaxies I: Testing birefringence solutions to the CMB-BAO tension
BibTeX
@misc{yin2026distinguishing,
title = {{Distinguishing the origin of cosmic birefringence: dark energy, dark matter, and neutrino asymmetry}},
author = {Lu Yin and Eiichiro Komatsu},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.02667},
eprint = {2610.02667},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.02667},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Distinguishing the origin of cosmic birefringence: dark energy, dark matter, and neutrino asymmetry
AU - Lu Yin
AU - Eiichiro Komatsu
PY - 2026
DA - 2026/10/02
PB - arXiv
DO - 10.48550/arxiv.2610.02667
UR - https://arxiv.org/abs/2610.02667
AB - Cosmic birefringence, the isotropic rotation of the plane of linear polarization of photons from sources at cosmological distances, can be generated by different parity-violating mechanisms. While the net rotation angle of a single polarized source carries little information about its physical origin, sources at various redshifts z can be used to distinguish between different origins. Parity-sensitive correlations of the E- and B-mode polarization fields of the cosmic microwave background measured on large and small angular scales probe sources at z≃ 10 and $1100$, respectively. Thus, the detailed shape of the EB power spectrum is sensitive to the redshift evolution of the birefringence source. In this paper, we calculate the EB power spectrum due to a neutrino-asymmetry current, and compare it to axion dark energy and dark matter using a common Chern--Simons framework. We find that the EB power spectrum due to a neutrino asymmetry is suppressed at low multipoles, ℓ≲ 20, similar to the dark matter case. This can be clearly distinguished from the dark energy case, which has no such suppression. Large-scale polarization measurements, including \textit{LiteBIRD}, can therefore distinguish late-time dark energy birefringence from that generated at higher redshifts by axion dark matter or neutrino asymmetry. We also find that the evolution of the neutrino density during recombination alters the shape of the EB power spectrum at high multipoles. This signature can be used to distinguish between the neutrino and axion dark matter interpretations, using ground-based experiments such as the Simons Observatory.
ER -