Inflationary solutions in asymptotically safe f(R) theories

TL;DR

This paper investigates inflationary solutions within asymptotically safe f(R) gravity theories, demonstrating that certain polynomial models admit reliable power law and exponential inflationary solutions near a nontrivial ultraviolet fixed point.

Contribution

It introduces inflationary solutions in renormalization group improved polynomial f(R) theories linked to asymptotic safety in quantum gravity, showing their reliability at high polynomial orders.

Findings

Existence of power law and exponential inflationary solutions.

Solutions are reliable at sufficiently high polynomial orders.

Modified Friedmann equations support inflation in these models.

Abstract

We discuss the existence of inflationary solutions in a class of renormalization group improved polynomial f(R) theories, which have been studied recently in the context of the asymptotic safety scenario for quantum gravity. These theories seem to possess a nontrivial ultraviolet fixed point, where the dimensionful couplings scale according to their canonical dimensionality. Assuming that the cutoff is proportional to the Hubble parameter, we obtain modified Friedmann equations which admit both power law and exponential solutions. We establish that for sufficiently high order polynomial the solutions are reliable, in the sense that considering still higher order polynomials is very unlikely to change the solution.