Quantum Aspects of Massive Gravity II: Non-Pauli-Fierz Theory

TL;DR

This paper explores the non-Pauli-Fierz massive gravity theory, demonstrating that the Lee-Wick mechanism can address its ghost issue, potentially making it a viable large-scale gravity modification consistent with quantum principles.

Contribution

It shows how to use the Lee-Wick mechanism to handle ghosts in non-Pauli-Fierz massive gravity, establishing quantum consistency and viability for large-distance gravity modifications.

Findings

The ghost in non-Pauli-Fierz theory can be managed via the Lee-Wick mechanism.

The theory remains stable under radiative corrections.

It naturally converges to general relativity at short distances.

Abstract

We investigate the non-Pauli-Fierz(nPF) theory, a linearized massive gravity with a generic graviton mass term, which has been ignored due to a ghost in its spectrum and the resultant loss of unitarity. We first show that it is possible to use the Lee-Wick mechanism, a unitarization through the decay of a ghost, in order to handle the sixth mode ghost of nPF, and then check for the quantum consistency. Once proven to be consistent, nPF could become a viable candidate for a large distance modification of gravity, because it naturally solves the intrinsic problems that most dark energy/modified gravity models suffer from: It smoothly converges to general relativity at short distances, and the small graviton mass necessary to modify gravity at large scales can be stable under the radiative corrections from the minimal gravity-to-matter coupling.