Massive Gravity Acausality Redux
arXiv:1306.5457 · doi:10.1016/j.physletb.2013.09.001
Abstract
Massive gravity (mGR) is a 5(=2s+1) degree of freedom, finite range extension of GR. However, amongst other problems, it is plagued by superluminal propagation, first uncovered via a second order shock analysis. First order mGR shock structures have also been studied, but the existence of superluminal propagation in that context was left open. We present here a concordance of these methods, by an explicit (first order) characteristic matrix computation, which confirms mGR's superluminal propagation as well as acausality.
16 pages LaTeX, references added, Physics Letters B version