Decoupling during inflation, and the effects of heavy physics in the Cosmic Microwave Background

by Dr Vincent Atal (Leiden University - Olanda)

Wednesday 11 Nov 2015, 15:00 → 16:00 Europe/Rome

Aula Teorici (Dipartimento di Fisica e Astronomia)

In this talk we present how heavy fields may influence low-energy observables during the period of cosmic inflation. Contrary to expectations, fields much heavier than the Hubble parameter can largely affect the dynamics of the low energy curvature perturbations, by inducing a reduction in the speed of sound and/or changes in the effective potential. This demands taking a close look at the multifield dynamics and the way in which the decoupling between the different energy scales is operative. The effects of a heavy field in the low-energy EFT may be divided in two phenomenological classes, depending on whether they are transient or sustained over time. We discuss the search for their observational signatures, such as oscillatory features in the n-point correlation functions and non-gaussianity in the CMB statistics.