Quasi-topological mass generation for 3D linearized gravity

Abstract: We present a new mass generation mechanism for linearized gravity in three spacetime dimensions, which consists of a lower-dimensional Chern-Simons-like term added to the invariant action. The propagators of the gauge fixed massive action show a massive pole and a good massless limit. Moreover, we show that, as the Topological Massive Gravity model of Deser, Jackiw and Templeton, this theory displays one propagating massive DoF, which can be traced back to the transverse part of the spatial Ricci tensor. Finally, the action of this linearized massive gravity is characterized by an algebraic structure formed by a set of Ward operators, which uniquely determine the theory.