论文标题
宇宙学21cm圆极化的标准模型预测
Standard Model Prediction for Cosmological 21cm Circular Polarization
论文作者
论文摘要
在宇宙电离之前，氢原子通过与各向异性21-CM辐射场相互作用而获得自旋极化四极。这四极杆与各向异性在宇宙微波背景（CMB）辐射场中的相互作用给出了氢原子的净旋转方向。这些面向自旋的氢原子发射的21厘米辐射是圆极化的。在这里，我们根据笛卡尔（而不是球形）张量，简洁地重新重新将这种圆极化的表达推导。然后，我们计算标准$λ$ CDM宇宙学模型中观察到的Stokes-$ v $参数的角功率谱，并显示其如何依赖于红移或等效地（观察到的频率）。
Before cosmic reionization, hydrogen atoms acquire a spin polarization quadrupole through interaction with the anisotropic 21-cm radiation field. The interaction of this quadrupole with anisotropies in the cosmic microwave background (CMB) radiation field gives a net spin orientation to the hydrogen atoms. The 21-cm radiation emitted by these spin-oriented hydrogen atoms is circularly polarized. Here, we reformulate succinctly the derivation of the expression for this circular polarization in terms of Cartesian (rather than spherical) tensors. We then compute the angular power spectrum of the observed Stokes-$V$ parameter in the standard $Λ$CDM cosmological model and show how it depends on redshift, or equivalently, the observed frequency.
