Alternative approach to the Starobinsky model for inflation scenarios

TL;DR

This paper proposes a dynamical mechanism for the emergence of the Starobinsky inflation model, analyzing its parameter constraints, primordial perturbations, and non-Gaussianities to extend understanding of early Universe inflation scenarios.

Contribution

It introduces a novel dynamical approach to derive the Starobinsky model, providing new insights into its parameter constraints and primordial perturbation characteristics.

Findings

Constraints on model parameters to avoid ghost modes

Predictions for scalar spectral index and tensor-to-scalar ratio

Estimation of primordial non-Gaussianities

Abstract

The $R+R^2$ model of gravity with the corresponding shallow potential in the Einstein frame is consistent with the observations. Recently, many efforts have been made to generalize the $R+R^2$ (Starobinsky) model of inflation or use other shallow potentials to construct a model for the early Universe. We revise the question about the shallow potential. We propose a model in which the Starobinsky model can emerge through a dynamical mechanism. We show that the absence of ghost modes results to constraints on the parameters of the Starobinsky model. We obtain the scalar spectral index and the tensor-to-scalar ratio of the extended model and study the three-point correlation function of the curvature perturbation to estimate the primordial non-Gaussianities of the proposed model.