Inflationary scenarios in Starobinsky model with higher order corrections

TL;DR

This paper explores how higher order corrections in the Starobinsky inflation model affect its potential, identifying different inflationary regimes and analyzing stability and parameter constraints for successful inflation.

Contribution

It introduces a parametrized set of higher order corrections to the Starobinsky model, analyzing resulting potential features and inflationary behaviors not previously detailed.

Findings

Identified three inflationary regimes: plateau, local maximum, and saddle point.

Derived parameter constraints for successful and non-eternal inflation.

Confirmed stability of the local minimum away from the GR vacuum.

Abstract

We consider the Starobinsky inflation with a set of higher order corrections parametrised by two real coefficients $\lambda_1, \lambda_2$. In the Einstein frame we have found a potential with the Starobinsky plateau, steep slope and possibly with an additional minimum, local maximum or a saddle point. We have identified three types of inflationary behaviour that may be generated in this model: i) inflation on the plateau, ii) at the local maximum (topological inflation), iii) at the saddle point. We have found limits on parameters $\lambda_i$ and initial conditions at the Planck scale which enable successful inflation and disable eternal inflation at the plateau. We have checked that the local minimum away from the GR vacuum is stable and that the field cannot leave it neither via quantum tunnelling nor via thermal corrections.