We compare the effects of local features (LF) and branch features (BF) of the inflaton potential on the spectrum of primordial perturbations. We show that LF affect the spectrum in a narrow range of scales while BF produce a step between large and small scales with respect to the featureless spectrum. We comment on the possibility of distinguishing between these two types of feature models from the analysis of the Cosmic Microwave Background (CMB) radiation data.
We also show that there exists a quantitative similarity between the primordial spectra predicted by two of the BF potentials considered. This could lead to a degeneracy of their predicted CMB temperature spectra which could make difficult to discriminate between the models from a CMB analysis. We comment on the possibility that the degeneracy can be broken when higher order terms in the perturbations are considered. In this sense non-Gaussianity may play an important role in discerning between different inflationary models which predict similar spectra.
Tue, 14 Mar 17
Comments: To be published in Journal of Physics: Conference Series as the proceedings of the 70&70 Classical and Quantum Gravitation Party: Meeting with Two Latin American Masters on Theoretical Physics (Cartagena de Indias – Colombia, 28th-30th September, 2016)