Description
We propose a systematic way to classify inflationary models by using the most basic property of inflation: the approximate scaling invariance. This new framework relies on the possibility of describing inflation in terms of a renormalisation group equation. The slow rolling regime in this context is thus interpreted as the slow evolution close to a fixed point. This explains in part the universality observed in the predictions of a certain number of inflationary models. Our choice of describing inflation with a renormalisation group equation indeed is motivated by theoretical arguments. As suggested by Mc Fadden and Skenderis, it is interesting to provide an holography description for the inflationary universe. In the language of the well known (A)dS/CFT correspondence the departure from (Anti) de Sitter spacetime is mapped into a departure from conformal invariance which is described as usual by a renormalisation group equation.
