Zwei-Dreibein Gravity

TL;DR

This paper introduces a new three-dimensional gravity model called zwei-dreibein gravity, which unifies previous models, propagates two massive spin-2 modes unitarily, and aligns with the AdS/CFT correspondence.

Contribution

It presents a generally-covariant, parity-invariant action for 3D gravity that propagates two massive modes and extends previous models within the AdS/CFT framework.

Findings

Unitarily propagates two massive spin-2 modes

Unifies and extends previous 3D massive gravity models

Allows for a positive central charge in AdS/CFT context

Abstract

We present a generally-covariant and parity-invariant "zwei-dreibein" action for gravity in three space-time dimensions that propagates two massive spin-2 modes, unitarily, and we use Hamiltonian methods to confirm the absence of unphysical degrees of freedom. We show how zwei-dreibein gravity unifies previous "3D massive gravity" models, and extends them, in the context of the AdS/CFT correspondence, to allow for a positive central charge consistent with bulk unitarity.