A Possible Test for Quadratic Gravity in $d \ge 4$ dimensions

TL;DR

This paper investigates the Einsteinian strengths and degrees of freedom in quadratic gravity theories across dimensions, highlighting differences between metric and torsion-admitting models in terms of their theoretical robustness.

Contribution

It introduces a comparative analysis of Einsteinian strengths and degrees of freedom for quadratic gravity theories, emphasizing the distinction between metric-only and torsion-inclusive models.

Findings

Purely metric quadratic gravity is stronger in Einsteinian sense.

Quadratic gravity theories with torsion are less robust.

The analysis provides insights into testing quadratic gravity in higher dimensions.

Abstract

In this letter we consider the Einsteinian strengths and dynamical degrees of freedom for quadratic gravity. We show that purely metric quadratic gravity theories are much stronger in Einsteinian sense than the competitive quadratic gravity theories which admit torsion.