Inflationary cosmology in modified gravity theories

TL;DR

This paper reviews inflationary models within modified gravity theories, demonstrating their consistency with observational data and exploring related phenomena like bounce cosmology.

Contribution

It generalizes the Starobinsky inflation model by incorporating modifications of gravity, quantum anomalies, and loop quantum cosmology effects.

Findings

Inflation models in modified gravity align with Planck data.

Explicit demonstration of spectral index and tensor-to-scalar ratio compatibility.

Discussion of bounce cosmology within $F(R)$ gravity.

Abstract

We review inflationary cosmology in modified gravity such as $R^2$ gravity with its extensions in order to generalize the Starobinsky inflation model. In particular, we explore inflation realized by three kinds of effects: modification of gravity, the quantum anomaly, and the $R^2$ term in loop quantum cosmology. It is explicitly demonstrated that in these inflationary models, the spectral index of scalar modes of the density perturbations and the tensor-to-scalar ratio can be consistent with the Planck results. Bounce cosmology in $F(R)$ gravity is also explained.