Validity and violation of the consistency relations in Cosmology

by Rocco Rollo


In this talk, the study of primordial non-Gaussianity (PNG) during inflation will be presented.
PNG can be considered one of the best avenues to probe inflation, trying to resolve the large degeneracy among different models still present after analyzing Cosmic Microwave Background data. Indeed, on the one hand, the amount of non-Gaussianity in single-field inflation is very tiny and entirely fixed by the spontaneous breaking of time reparameterization; on the other hand, different symmetry breaking patterns, typical of multi-field theories, lead to quite different predictions.
In this context, we will introduce a controversial issue regarding the observability of the consistency relation in single-field inflation. Later, we will discuss a completely different scenario (supersolid inflation) featuring the spontaneous symmetry breaking of both time and space reparametrization.