A Stueckelberg Approach to Quadratic Curvature Gravity and its Decoupling Limits

TL;DR

This paper employs the Stueckelberg trick to analyze quadratic curvature gravity, revealing how the theory can evade strong coupling limits and become renormalizable by decoupling massive modes, despite stability issues.

Contribution

It introduces a Stueckelberg framework to study the high-energy behavior of quadratic curvature gravity and its decoupling limits, providing insights into renormalizability and stability.

Findings

The Stueckelberg approach clarifies the interplay between ghost and healthy gravitons.

The theory can evade the lambda-3 strong coupling scale of massive gravity.

Decoupling limits lead to a potentially renormalizable gravity theory.

Abstract

Curvature squared terms, when added to the Einstein-Hilbert action and treated non-perturbatively, generically result in the propagation of an extra massive scalar state and an extra massive spin-2 ghost state. Using the Stueckelberg trick, we study the high-energy limit in which the mass of the spin-2 state is taken to zero, with strong- coupling scales held fixed. The Stueckelberg approach makes transparent the interplay between the ghost graviton and the healthy graviton which allows the theory to evade the usual lambda-3 strong coupling scale of massive gravity and become renormalizable, at the expense of stability.