Paolo Creminelli, Jorge Noreña, Marko Simonović, Manuel Peña
We study the possibility that the approximate time shift symmetry during inflation is promoted to the full invariance under time reparametrization t \to \tilde t(t), or equivalently under field redefinition of the inflaton \phi \to \tilde\phi(\phi). The symmetry allows only two operators at leading order in derivatives, so that all n-point functions of scalar perturbations are fixed in terms of the power spectrum normalization and the speed of sound. During inflation the decaying mode only decays as 1/a and this allows to violate some of the consistency relations in the squeezed limit. In particular the 3-point function is only suppressed by 1/k_L in the squeezed limit k_L \to 0 compared to the local shape.
View original:
http://arxiv.org/abs/1206.1083
No comments:
Post a Comment