Speaker
Description
Cosmic inflationary models predict a background of primordial gravitational waves that would imprint a B-mode polarization signature in the cosmic microwave background (CMB). The South Pole Observatory (SPO), a joint effort between BICEP and the South Pole Telescope (SPT), aims to constrain the strength of this signature, parameterized by the tensor-to-scalar ratio r, and thereby constrain the energy scale of inflation. B-mode results using BICEP data through the 2018 observing season continue to be world-leading in constraining r (r < 0.036 at 95% confidence) at an uncertainty of σ(r) = 0.009. At levels lower than this, gravitational lensing of the CMB from large-scale structure becomes a key foreground that contributes to the uncertainty. SPO plans to leverage the higher angular resolution of SPT to enable delensing of the CMB to separate out primordial B-modes from the lensing foreground and push to lower uncertainty. Hardware improvements will also play a major role, including the upcoming BICEP Array 90/150 GHz receiver and SPT-3G+ camera. In this talk, I will summarize the history up to the current state of r constraints, give a preview for BICEP and SPT hardware upgrades, and present SPO’s road map for reaching σ(r) ~ 0.001 by 2034.