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

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.