Probing inflationary cosmology with BICEP-Keck small aperture telescopes

This talk will overview the trajectory of small aperture telescopes, deployed by the BICEP-Keck collaboration, to understand the process of inflation. We will review the state-of-the art and the future CMB-Stage4 project in this regard. Cosmic Microwave Background (CMB) measurements indicate a period of inflation occurred immediately following the Big-Bang, during which the universe expanded some 60 e-folds and primordial gravitational waves (PGWs) were generated. PGWs are tensor perturbations and leave their signature on the CMB as polarized anisotropies, commonly called B-modes. Detection of B-modes will directly probe inflation and will reveal physics at 10^16 GeV energy-scales, a trillion times larger than any terrestrial collider experiment. The BICEP-Keck collaboration has been leading the search for B-modes with a suite of small aperture telescopes (SATs) operating from the South Pole. This talk will introduce the physics behind B-modes, the signals that are being pursued and the cutting-edge technologies behind these telescopes. Today BICEP-Array is fielding four SATs which will measure the polarized CMB and associated foregrounds to unprecedented precision, charting the way for CMB-Stage 4. CMB-Stage 4 is a major collaborative undertaking to comprehensively map the CMB-sky and will set the ultimate standards for PGW detection with B-mode surveys. See talks by Hui on latest groundbreaking BICEP/Keck results, Yu for introduction to BICEP-Array and multicomponent analysis, Cheshire on performance of BICEP-Array and the future reach of the program and Fatigoni on Polar atmospheric monitoring for improving CMB sensitivities.