Cosmic 21-cm Delensing of Microwave Background Polarization and the Minimum Detectable Energy Scale of Inflation

Preprint
Publisher Website
Google Scholar
Abstract
The curl (B) modes of cosmic microwave background (CMB) polarization anisotropies are a unique probe of the primordial background of inflationary gravitational waves (IGWs). Unfortunately, the B-mode polarization anisotropies generated by gravitational waves at recombination are confused with those generated by the mixing of gradient-mode (E-mode) and B-mode polarization anisotropies as CMB photons propagate through the Universe and are gravitationally lensed. We describe here a method for delensing CMB polarization anisotropies using observations of anisotropies in the cosmic 21-cm radiation emitted or absorbed by neutral hydrogen atoms at redshifts 10 to 200. While the detection of cosmic 21-cm anisotropies at high resolution is challenging, a combined study with a relatively low-resolution (but high-sensitivity) CMB polarization experiment could probe inflationary energy scales well below the Grand Unified Theory (GUT) scale of 10^{16} GeV -- constraining models with energy scales below 10^{15} GeV (the detectable limit derived from CMB observations alone). The ultimate theoretical limit to the detectable inflationary energy scale via this method may be as low as 3 \times 10^{14} GeV.

This publication has 0 references indexed in Scilit: