# (2+1)-dimensional interacting model of two massless spin-2 fields as a bi-gravity model

## TL;DR

This paper introduces a new Chern-Simons formulation for a (2+1)-dimensional bi-gravity model with two interacting massless spin-2 fields, using a mixed AdS-AdS algebra, and explores its boundary CFT and cosmological implications.

## Contribution

It presents a novel group-theoretical Chern-Simons approach to bi-gravity in (2+1) dimensions using a mixed AdS-AdS algebra, with boundary CFT analysis.

## Key findings

- Model formulated with two dreibeins instead of metrics
- Boundary CFT has central charge proportional to AdS mass
- Cosmological implications of the bi-gravity model analyzed

## Abstract

We propose a new group-theoretical (Chern-Simons) formulation for the bi-metric theory of gravity in (2+1)-dimensional spacetime which describe two interacting massless spin-2 fields. Our model has been formulated in terms of two dreibeins rather than two metrics. We obtain our Chern-Simons gravity model by gauging {\it mixed AdS-AdS Lie algebra} and show that it has a two dimensional conformal field theory (CFT) at the boundary of the anti de Sitter (AdS) solution. We show that the central charge of the dual CFT is proportional to the mass of the AdS solution. We also study cosmological implications of our massless bi-gravity model.