AI 中文总结
本研究联合分析ACT与Planck的偏振数据，发现宇宙双折射角非零，统计显著性达4.8σ，排除β=0°，但需进一步明确数据中的系统误差以得出可靠结论。
AI 中文摘要
暗物质与暗能量可能是超轻赝标量场，它们通过陈-西蒙斯项与电磁相互作用，这会导致宇宙微波背景中线性偏振光的偏振面发生宇称破缺旋转，该现象被称为宇宙双折射，而ΛCDM模型并未预测这一现象。近期，Planck数据发布4（Planck Data Release 4）与ACT数据发布6（ACT Data Release 6）的独立分析均发现了非零宇宙双折射角的迹象。本研究对两者的偏振图进行联合分析，利用两台望远镜之间的交叉功率谱，在直接采用已报道的仪器先验的情况下，联合分析得到β=0.277°±0.057°，其非零的统计显著性达4.8σ。针对尘埃发射污染的稳健性检验以3.5σ的置信度排除β=0°，若要得到β=0°的结果，则需尘埃EB建模与仪器先验同时失效。不过，在得出可靠的宇宙学结论前，必须明确数据中未解决的系统误差。
英文摘要
Dark matter and dark energy could be ultra-light pseudoscalar fields that couple to electromagnetism through a Chern-Simons term. This would cause a parity-breaking rotation of the plane of linearly polarized light from the cosmic microwave background, known as cosmic birefringence, which is not predicted by $Λ$CDM. Recent hints of a non-zero cosmic birefringence angle have been found in both the Planck Data Release 4 and ACT Data Release 6 datasets independently. This work jointly analyzes the polarized maps of both, leveraging the cross-power spectra between the two telescopes. Taking the reported instrumental priors at face value, the joint analysis yields $β= 0.277^{\circ} \pm 0.057^{\circ}$, which is non-zero with a statistical significance of $4.8σ$. A robustness test mitigating contamination from dust emission excludes $β= 0^{\circ}$ at $3.5σ$, and retrieving $β=0^{\circ}$ would require both the dust $EB$ modeling and instrumental priors to fail simultaneously. However, unresolved systematics in the data must be understood before we can draw strong cosmological conclusions.
Comments8 pages, 5 figures. The code to reproduce the results of this paper is available at https://github.com/LilleJohs/cosmic-birefringence-planck-act
