Unitarity and Different Phases of the Extended New Massive Gravity
arXiv:1912.09101 · doi:10.1103/PhysRevD.101.124018
Abstract
We study the New Massive Gravity extended by the curvature cubed invariant and the Cosmological Constant using the tree-level scattering amplitudes on a maximally symmetric space-time. We identify the parameter space, consisting of the ratio between C.C. and graviton mass squared and the relative coupling strength between curvature squared and cubed invariants, for which the massive spin-2 is a ghost. Different phases of this model are also discussed.
1+10 pages, 3 figures; v2: comments added; published in PRD