Massive Vector Chern-Simons Gravity

TL;DR

This paper introduces a novel second order gravity theory combining Einstein gravity with a vector-like Chern-Simons term, which is ghost-free, propagates only spin-2 modes, and exhibits spontaneous Lorentz symmetry breaking.

Contribution

It presents a new ghost-free, diffeomorphism-invariant gravity model with a vector Chern-Simons term that breaks local Lorentz invariance spontaneously.

Findings

Propagates a pure spin-2 mode

Is ghost-free and diffeomorphism invariant

Features spontaneous Lorentz symmetry breaking

Abstract

We present a second order gravity action which consists of ordinary Einstein action augmented by a first-order, vector like, Chern-Simons quasi topological term.This theory is ghost-free and propagates a pure spin-2 mode. It is diffeomorphism invariant, although its local Lorentz invariance has been spontaneously broken.