Large N Quantum Gravity

TL;DR

This paper derives the effective action for four-dimensional quantum gravity with many matter fields, highlighting how key quantum gravity phenomena are represented in the large N limit through curvature expansions.

Contribution

It provides a large N approximation framework for quantum gravity, connecting asymptotic safety, quantum corrections, and anomalies via the effective action.

Findings

Effective action derived in the large N limit.

Representation of quantum gravity aspects in curvature expansion.

Insights into quantum corrections and anomalies.

Abstract

We obtain the effective action of four dimensional quantum gravity, induced by N massless matter fields, by integrating the RG flow of the relative effective average action. By considering the leading approximation in the large N limit, where one neglects the gravitational contributions with respect to the matter contributions, we show how different aspects of quantum gravity, as asymptotic safety, quantum corrections to the Newtonian potential and the conformal anomaly induced effective action, are all represented by different terms of the effective action when this is expanded in powers of the curvature.