In the last few decades, measurements of the Cosmic Microwave Background (CMB), microwave-wavelength light generated when the Universe was in its infancy, have revolutionized our knowledge about the origins and history of the Universe, and hold promise for probing the Universe’s earliest moments. Currently, observations of the CMB are being used to test the theory of Inflation, which postulates that the Universe underwent a period of rapid expansion less than 10^-32 seconds after birth, seeding the Universe with the first hints of structure. Inflation is also predicted to have launched gravitational waves that would have imprinted a subtle curl pattern, or B-modes, in the polarization of the CMB light on degree angular scales. At sub-degree angular scales, theories predict that B-mode polarization would arise due to gravitational lensing by intervening matter. This lensing signal can be used to place constraints on the structure formation history of the universe and the mass of the neutrino.
In this talk, I will review the promise that precision measurements of CMB polarization hold to reveal the fundamental nature of our universe, and will describe several next-generation CMB experiments with the potential to constrain the inflationary signal and neutrino mass, including the South Pole Telescope, Polarbear/Simons Array, and the LiteBIRD CMB satellite mission.