Conformally reduced quantum gravity revisited

TL;DR

This paper revisits conformally reduced quantum gravity using functional renormalization group methods, exploring different RG definitions and their implications for fixed points in a simplified four-dimensional model.

Contribution

It introduces two inequivalent approaches to defining the RG in conformally reduced gravity, explicitly considers the trace anomaly, and connects with previous research.

Findings

Presence or absence of fixed points depends on truncation and approximations

Explicit inclusion of the trace anomaly affects RG flow

Comparison of two RG definitions in conformally reduced gravity

Abstract

Applying functional renormalization group methods, we describe two inequivalent ways of defining the renormalization group of matter-coupled four dimensional gravity, in the approximation where only the conformal factor is dynamical and taking the trace anomaly explicitly into account. We make contact with earlier work and briefly discuss the presence or absence of fixed points, depending on the truncation of the action and other approximations.