Gauge dependence of momentum running in higher-derivative gravity

TL;DR

This paper investigates the gauge dependence of the momentum running in higher-derivative gravity theories, revealing that the one-loop beta-functions are gauge dependent, which questions their physical interpretability.

Contribution

It provides the first explicit calculation of gauge dependence of the one-loop momentum running in quadratic and conformal gravity theories.

Findings

One-loop momentum running is gauge dependent.

Gauge dependence challenges the physical predictivity of these beta-functions.

Results suggest caution in interpreting high-energy behavior from these functions.

Abstract

Recent works have argued that improved one-loop beta-functions capturing the physical momentum dependence of one-loop corrected higher-derivative gravity theories are the most suitable to describe their high-energy behaviour. This work critically tests the validity of this claim. We compute the explicit gauge dependence of the one-loop momentum running of curvature-squared operators in quadratic gravity and conformal gravity using the background field method. We find them to be gauge dependent, and we discuss the implications of this result for the theory and its physical predictivity.