Planck 2013 and Superconformal Symmetry

Abstract

We explain why the concept of a spontaneously broken superconformal symmetry is useful to describe inflationary models favored by the Planck. Non-minimal coupling of complex scalars to curvature, N(X, X*) R, is compulsory for superconformal symmetry. Here N is the Kahler potential of the embedding moduli space, including the inflaton and the conformon. It appears that such a non-minimal coupling allows generic chaotic models of inflation to reach an agreement with the observable (n_{s},r) values. We describe here the superconformal versions of the cosmological attractors whose bosonic part was presented in lectures of A. Linde in this volume. A distinguishing feature of this class of models is that they tend to lead to very similar predictions which are not very sensitive with respect to strong modifications of the theory. The (super)conformal symmetry underlying (super)gravity allows a universal description of a large class of models which agree with observations and predict the tensor to scalar ratio 10^{-3} < r < 10^{-1}.