Massive spin-2 theories

Abstract

We give an introduction to massive spin-2 theories and the problem of their non-linear completion. We review the Boulware-Deser ghost problem and two ways to circumvent classic no-go theorems. In turn, massive spin-2 theories are not uniquely defined. In the case of truncated theories, we show that the Boulware-Deser ghost may only be avoided if the derivative structure of the theory is not tuned to be Einsteinian.

Comments: 14 pages - Invited review for the Central European Journal of Physics, topical issue devoted to "Cosmology and Particle Physics beyond Standard Models". v2: References added, extended discussion on massive gravity