Inflationary universe from higher-derivative quantum gravity

TL;DR

This paper explores how higher-derivative quantum gravity can produce an inflationary universe, analyzing its stability and compatibility with observational data through quantum-corrected equations and slow-roll parameters.

Contribution

It derives a renormalization group improved effective action for higher-derivative quantum gravity and analyzes its implications for inflationary cosmology, including stability and observational consistency.

Findings

De Sitter universe solution is found but is unstable.

Quantum corrections yield slow-roll parameters consistent with Planck data.

Gauss-Bonnet term influences stability and observable predictions.

Abstract

We consider higher-derivative quantum gravity where renormalization group improved effective action beyond one-loop approximation is derived. Using this effective action, the quantum-corrected FRW equations are analyzed. De Sitter universe solution is found. It is demonstrated that such de Sitter inflationary universe is instable. The slow-roll inflationary parameters are calculated. The contribution of renormalization group improved Gauss-Bonnet term to quantum-corrected FRW equations as well as to instability of de Sitter universe is estimated. It is demonstrated that in this case the spectral index and tensor-to-scalar ratio are consistent with Planck data.