标题： 宇宙双折射可观测量的协变对称性分类 显示英文标题

标题： Covariant Symmetry Classifications for Observables of Cosmological Birefringence

摘要： 电磁波来自遥远星系的偏振已知与源方向相关。 这些量已被用于搜索宇宙学双折射的信号。 我们回顾并分类偏振和源方向可观测量的变换性质。 这些分类为文献中非正式出现的某些做法提供了坚实的基础。 在宇称变换下起核心作用，表明发射或随后传播中的宇称破坏是可观测现象。 我们还讨论了能正确变换的统计量、相关性和分布，这些可用于系统数据分析。 显示英文摘要

摘要： Polarizations of electromagnetic waves from distant galaxies are known to be correlated with the source orientations. These quantities have been used to search for signals of cosmological birefringence. We review and classify transformation properties of the polarization and source orientation observables. The classifications give a firm foundation to certain practices which have sprung up informally in the literature. Transformations under parity play a central role, showing that parity violation in emission or in the subsequent propagation is an observable phenomenon. We also discuss statistical measures, correlations and distributions which transform properly and which can be used for systematic data analysis.