Confronting cosmological tensions through precision CMB lensing

April 29, 2026 PIRSA:26040124 Conference Cosmology

Conference/School: Cosmological Frontiers in Fundamental Physics 2026

Qu, F. (2026). Confronting cosmological tensions through precision CMB lensing. Perimeter Institute. https://pirsa.org/26040124

Qu, Frank. Confronting cosmological tensions through precision CMB lensing. Perimeter Institute, Apr. 29, 2026, https://pirsa.org/26040124

@misc{ pirsa_PIRSA:26040124,
  doi = {10.48660/26040124},
  url = {https://pirsa.org/26040124},
  author = {Qu, Frank},
  keywords = {Cosmology},
  language = {en},
  title = {Confronting cosmological tensions through precision CMB lensing},
  publisher = {Perimeter Institute},
  year = {2026},
  month = {apr},
  note = {PIRSA:26040124 see, \url{https://pirsa.org}}
}

Abstract

The cosmic microwave background (CMB) serves as a unique backlight for tracing the growth of cosmic structures. By measuring arc-minute-scale deflections experienced by CMB photons due to gravitational lensing, we can map matter distributions at high redshifts. This lensing signal provides a powerful probe of fundamental physics, including the sum of neutrino masses, and enables critical tests of the standard cosmological model, particularly in light of the persistent S₈ tension and the puzzling preference for negative neutrino masses emerging from recent cosmological data combinations. In this talk, I will discuss how recent CMB lensing measurements have become one of our most robust probes for assessing cosmological tensions, focusing on the joint ACT, SPT, and Planck lensing analysis that delivered one of the most precise measurements of cosmic structure growth to date. I will also preview preliminary results from an upcoming updated analysis of ACT's final data release (DR6+), and discuss how these measurements, together with the Simons Observatory, can play a decisive role in probing new physics and resolving current cosmological tensions.