The phase diagram of quantum gravity from diffeomorphism-invariant RG-flows

TL;DR

This paper investigates the phase diagram of quantum gravity using a background-independent renormalisation group approach, providing evidence for an ultraviolet fixed point and a stable infrared fixed point, advancing understanding of quantum gravity's fundamental structure.

Contribution

It introduces a fully diffeomorphism-invariant RG approach based on the Vilkovisky-DeWitt effective action, resolving background metric issues and refining fixed point analysis in quantum gravity.

Findings

Evidence for the ultraviolet fixed point scenario in quantum gravity.

Identification of a stable infrared fixed point related to classical Einstein gravity.

Quantitative updates on fixed point properties in the phase diagram.

Abstract

We evaluate the phase diagram of quantum gravity within a fully diffeomorphism-invariant renormalisation group approach. The construction is based on the geometrical or Vilkovisky-DeWitt effective action. We also resolve the difference between the fluctuation metric and the background metric. This allows for fully background-independent flows in gravity. The results provide further evidence for the ultraviolet fixed point scenario in quantum gravity with quantitative changes for the fixed point physics. We also find a stable infrared fixed point related to classical Einstein gravity. Implications and possible extensions are discussed.