Non-Standard Mechanisms for Cosmic Microwave Background B-mode Production

在宇宙微波背景（CMB）中寻找起源于早期宇宙中引力波的原始B模式偏振信号是许多当代和未来实验的主要科学目标。然而，一些宇宙学效应和仪器设计的不完善也可能导致B模式污染原始信号。在这个项目中，我们将研究这些系统的仪器缺陷，和宇宙学效应，可能源B-模式，称为宇宙学双折射CB。CB效应涉及赝标量场（例如轴子）与光子之间的超标准模型耦合，其可以产生CMB光子的线性偏振角的均匀或方向相关的旋转。

The search for the primordial B-mode polarization signal in the cosmic microwave back- ground (CMB), sourced by gravitational waves in the early universe, is a primary science goal of many contemporary and future experiments. However, a number of cosmological effects and imperfections in instrument design may also source B-modes that may contaminate the primordial signal. In this project we will study these systematic instrument imperfections, and a cosmological effect, that may source B-modes, known as cosmological birefringence CB. The CB effect involves a beyond standard model coupling between a pseudo-scalar field (such as the axion) and the photon that can generate either a uniform, or a direction dependent rotation of the linear polarization angle of CMB photons.