Evidence is mounting that the entire universe was spawned in a superluminal “inflation” of a sub-nuclear volume. This process would have produced a gravitational-wave background, which leaves a distinct curly pattern in the Cosmic Microwave Background (CMB) polarization known as the B-modes. We seek funding to support the BICEP3 experiment, the latest major expansion to the BICEP/Keck program looking for this feature. In March 2014, BICEP2, the second generation of this series, reported a clear B-mode signal that appear to be consistent with inflationary predictions. BICEP2's measurements are made at a single microwave frequency, however, leaving open other interpretations for the origin of the signal. These possibilities could be conclusively distinguished by BICEP3's data at a different frequency.

BICEP3 will start observation in 2015 at the South Pole. Together with BICEP2 and Keck Array, the program will produce deep polarization maps at multiple frequency bands. These data sets could confirm the cosmological origin of the BICEP2 signal beyond any reasonable doubt, providing invaluable information on quantum gravity and our cosmic origin. Alternatively, it would provide the most comprehensive, the deepest search of the inflationary B-modes using well-established technologies and methodologies.

The BICEP3 instrument, as well as its operation, have been supported by the National Science Foundation (NSF). However, the awarded funding is only 50% of the requested amount, which was already the bare minimum for the anticipated calibration and analysis effort. The cut also reduces the originally planned 3 years of observation to 2 years. The funding of this proposal will restore the original 3-year observation/analysis plan.

BICEP3 will be executed by a team with exceptional track record in doing CMB experiments at the South Pole. This is a low-risk proposal that could potentially produce ground-breaking results with only a very modest investment.