The Cosmic Microwave Background (CMB) is the thermal glow from the Big Bang birth of our Universe. Studying its pattern has taught us an enormous amount about the content, evolution and fate of the Universe in which we find ourselves. Basic theory allows us to push our understanding back to an enormously high energy state, and infer the very particular set of conditions which pertained at that time - almost uniform plasma with Gaussian, scale free perturbations.

However, we need an even more radical theory dubbed "Inflation" to explain
how those conditions were set up. If inflation did in fact occur it will have injected into the fabric of spacetime a background of gravitational waves, and searching for this signal is currently one of the most important quests in all of contemporary physics.

The world leader in this field are the BICEP/Keck series of experiments which are located at the South Pole in Antarctica. This talk will describe the cosmological paradigm, the basics of the CMB, and then move on to how our telescopes work and how we search for the imprint of primordial gravitational waves in the polarization pattern of the CMB.

If you would like to follow the presentation via Zoom from outside APC, please contact Ken Ganga (gangaapc.univ-paris7.fr; note that APC personnel have already received the Zoom link from Matteo Cerruti and Sonia El Hedri).