Effective theory for quantum gravity

TL;DR

This paper explores an effective theory for quantum gravity, analyzing bounds on its parameters, and argues that astrophysical measurements are unlikely to improve existing bounds on certain curvature terms.

Contribution

It provides a detailed discussion on bounds of effective quantum gravity parameters and argues their natural size based on dimensional analysis.

Findings

Pulsar binary measurements are unlikely to improve bounds on $R^2$ and $R_{ u u}$ terms.

Coefficients of these terms should be at most of order unity if induced by quantum gravity.

The same applies to the non-minimal coupling of the Higgs to Ricci scalar.

Abstract

In this paper, we discuss an effective theory for quantum gravity and discuss the bounds on the parameters of this effective action. In particular we show that measurement in pulsars binary systems are unlikely to improve the bounds on the coefficients of the $R^2$ and $R_{\mu\nu} R^{\mu\nu}$ terms obtained from probes of Newton's potential performed on Earth. Furthermore, we argue that if the coefficients of these terms are induced by quantum gravity, they should be at most of order unity since $R^2$ and $R_{\mu\nu} R^{\mu\nu}$ are dimension four operators. The same applies to the non-minimal coupling of the Higgs boson to the Ricci scalar.