Testing cosmic tensions with new measurements of CMB lensing and the equality scale
5. November 2021 - 11:30
Blake Sherwin (University of Cambridge)
Abstract: Despite the remarkable success of the LCDM model overall, tensions have been reported between CMB and low-redshift measurements of the amplitude of density fluctuations (sigma_8) and (more significantly) the Hubble constant. Although systematic errors are a likely explanation, new physics explanations would, of course, be the most exciting possibility. In the first part of my talk, I will discuss current progress in measurements of gravitational lensing in the cosmic microwave background (CMB) with the Atacama Cosmology Telescope. These CMB lensing measurements will soon provide some of the most powerful probes of the amplitude of density fluctuations and of neutrino masses. In the second part of my talk, I will discuss new methods to measure the Hubble constant from large-scale structure without information from the sound horizon scale, using instead the matter-radiation equality scale; such measurements can provide a consistency test for the Hubble constant with potential sensitivity to new physics.