UC San Diego

POLARBEAR is an experiment designed to measure the polarization of the cosmic microwave background (CMB). These measurements have scientific objectives spanning particle physics, cosmology, and astrophysics. The field of CMB polarization is rapidly evolving, with extraordinary progress being made on several fronts including the recently claimed detection of gravitational waves generated during cosmic inflation. This dissertation describes the POLARBEAR instrument and the measurements taken during its first season of observations. The results include the first evidence for a non-zero ClBB power spectrum at sub-degree angular scales, consistent with theoretical expectations