Centre de Physique Théorique

Agenda

Vendredi 3 mars 2023

14h00 – 15h00, BU, 0th floor

Cosmology and new physics

Giovanni Cabass (IAS, Princeton)

I review the two main observables that make cosmology one of the main avenues for discovering physics beyond the Standard Model : primordial Gravitational Waves and Large-Scale Structure. Primordial gravitational waves are quantum fluctuations of the metric during the epoch of cosmological inflation and source a peculiar pattern of polarization of the Cosmic Microwave Background, the so-called B modes. LSS observations, instead, probe the structure of the universe on its largest scales by looking at the clustering of galaxies. I discuss how B-mode experiments targeted at measuring primordial Gravitational Waves probe frequencies unaccessible to Earth- and space-based interferometers. They will allow us to answer fundamental questions about inflation, e.g. what was its energy scale, and to distinguish between different models for the potential of the inflaton field that drives the epoch of accelerated expansion. I show how recent developments in the "Cosmological Bootstrap" program have been instrumental in understanding the properties of primordial Gravitational Waves, more precisely their interactions and resulting primordial non-Gaussianity. I then discuss how the modern techniques of the Effective Field Theory of Large-Scale Structure are fundamental in discovering new light degrees of freedom and interactions in the dark sector, learning the composition and properties of dark matter, and constraining modified gravity. I conclude by showing how these techniques applied to the analysis of data from the BOSS galaxy survey allow to learn about the properties (mass, spin, speed of propagation) of light degrees of freedom during inflation.

Agenda