# Features in single field slow-roll inflation

## TL;DR

This paper compares local and branch features in single-field slow-roll inflation, analyzing their effects on primordial spectra and discussing how CMB data and non-Gaussianity could distinguish between models.

## Contribution

It provides a detailed comparison of local and branch potential features and explores their observational signatures and degeneracies in CMB spectra.

## Key findings

- LF affect a narrow scale range in the spectrum
- BF produce a step-like feature in the spectrum
- Degeneracy between some BF models can be broken by non-Gaussianity analysis

## Abstract

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.