Modified Starobinsky Inflation

TL;DR

This paper explores a modified Starobinsky inflation model incorporating quantum corrections, analyzing its inflationary dynamics, compatibility with CMB data, and reheating process, to assess its viability as an alternative to the original model.

Contribution

It introduces a quantum-corrected inflation model with R^2 and R^2 log(R) terms, and evaluates its observational viability and reheating behavior.

Findings

The model's parameters can be tuned to fit CMB observations.

Quantum corrections influence the inflationary potential.

Reheating dynamics are consistent with the modified model.

Abstract

Starobinsky has suggested an inflation model which is obtained from the vacuum Einstein's equations modified by the one-loop corrections due to quantized matter fields. Although the one-loop gravitational action is not known for a general FRW background, it can be obtained in a de Sitter space to give $\Mp^2 R + \alpha R^2 + \beta R^2 \ln (R/M^2)$. Thus, one needs to investigate the inflationary behavior of this model compared to the Starobinsky model (i.e. $\beta = 0$). The coefficient $\alpha$ can be changed by varying the renormalization scale $M^2$ and $\beta$ is obtained from the quantum anomaly which is related to the numbers of quantum fields. It has been assumed that $\alpha \gg \beta$. We investigate the viable values of $\alpha$ and $\beta$ based on the CMB observation. We also scrutinize the reheating process in this model.