Conformal Invariance in Inflation

During Inflation the universe was approximately described by deSitter (dS) space. The symmetries of 4-dimensional dS space are the same as those of a 3-dimensional Euclidean Conformal field Theory. We will discuss how these symmetries impose important constraints on the correlation functions of perturbations produced during inflation. Using these symmetry considerations, we will understand the Ward identities for conformal invariance, imposing restrictions on those correlation functions.