Possible Derivative Interactions in Massive bi-Gravity
arXiv:1704.08603
Abstract
Using the metric formalism, we study the derivative mixings of spin-2 fields in massive bi-Gravity. Necessary (but not sufficient) criteria are given for such mixings to be ghost free. Examples satisfying those criteria are studied and it is shown that in the decoupling limit they host a ghost.
13 pages, 2 figures