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