An exponential correction to Starobinsky's inflationary model

TL;DR

This paper examines modifications to Starobinsky's inflationary model by adding an exponential term to the $f(R)$ gravity Lagrangian, analyzing its dynamical implications and potential effects on inflationary predictions.

Contribution

It introduces a novel exponential correction to Starobinsky's model and explores its impact on inflationary predictions, testing the model's robustness.

Findings

The exponential correction influences the inflationary dynamics.

The modified model affects the scalar spectral index predictions.

Potential for new observational tests of the inflationary scenario.

Abstract

We analyse $f(R)$ theories of gravity from a dynamical system perspective, showing how the $R^2$ correction in Starobinsky's model plays a crucial role from the viewpoint of the inflationary paradigm. Then, we propose a modification of Starobinsky's model by adding an exponential term in the $f(R)$ Lagrangian. We show how this modification could allow to test the robustness of the model by means of the predictions on the scalar spectral index $n_s$.