Quasi-topological mass generation for 3D linearized gravity

TL;DR

This paper introduces a novel mass generation method for 3D linearized gravity using a Chern-Simons-like term, resulting in a theory with a single massive degree of freedom and a well-defined massless limit.

Contribution

It proposes a new mass generation mechanism for 3D linearized gravity involving a Chern-Simons-like term, with a detailed analysis of its propagators and algebraic structure.

Findings

The theory exhibits a massive pole in the propagator.

It has a good massless limit.

The model propagates one massive degree of freedom.

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.