Asymptotically safe inflation from quadratic gravity

TL;DR

This paper explores inflationary models derived from quantum gravity modifications of quadratic gravity, emphasizing the role of non-integer power operators near a non-Gaussian fixed point and their compatibility with Planck data.

Contribution

It introduces a class of inflationary models based on asymptotically safe gravity with non-integer power operators, linking quantum gravity effects to cosmological inflation.

Findings

Constraints on new couplings from Planck data

Presence of non-integer power operators in effective Lagrangian

Viability of asymptotically safe inflation models

Abstract

Asymptotically Safe theories of gravity have recently received much attention. In this work we discuss a class of inflationary models derived from quantum-gravity modification of quadratic gravity according to the induced scaling around the non-Gaussian fixed point at very high energies. It is argued that the presence of a three dimensional ultraviolet critical surface generates operators of non-integer power of the type $R^{2-\theta/2}$ in the effective Lagrangian, where $\theta>0$ is a critical exponent. The requirement of a successful inflationary model in agreement with the recent Planck 2015 data puts important constraints on the strenght of this new type of couplings.