Joint Astrophysics Colloquium

CMB Polarimetry and the Search for Inflationary Gravitational Waves

John Kovac

JPL / Caltech

Inflation predicts a cosmic gravitational-wave background (CGB), the amplitude of which measures the Inflationary energy scale. The CGB in turn produces a faint but unique signature in the ‘B-mode’ polarization of the cosmic microwave background (CMB). BICEP, the first experiment specifically designed to search for this signature, began observing from the South Pole in early 2006 and has produced the highest sensitivity measurements yet made of CMB polarization at the ~2 degree angular scales where the inflationary signal is expected to peak. A sister experiment, QUAD, is pushing the limits of CMB polarimetry at smaller angular scales where measurements of B-modes from lensing promise a sensitive probe of the Dark Energy equation of state, the sum of neutrino masses, and improved constraints on Inflation. Lessons learned from these pathfinder projects inform the next generation of efforts to probe fundamental physics through CMB polarization.