First Light: Using the Cosmic Microwave Background to Constrain Physics and Cosmology

Observations of the cosmic microwave background (CMB) has been spectacularly successful in providing precise answers to age-old questions, including the age, geometry, and composition of the universe. CMB data are often analyzed in conjunction with other cosmological data. While this provides significantly improved constraints, at times it also highlights tensions between observations. The tensions could indicate underestimated measurement errors or could be due to exciting physics that has been missed. Understanding the detailed nature of the tensions is crucial so as not to miss new physics. The CMB has yet to be fully explored and current experiments are aimed at sensitive measurements of CMB polarization at a wide range of angular scales. New discoveries may relate to inflation, neutrino masses, reionization, cosmological birefringence (caused by the coupling between the cosmic scalar field and the CMB photons) or completed unexpected new physics. This talk will provide an overview of the field and select recent advances.