New Bi-Gravity from New Massive Garvity

TL;DR

This paper introduces a new three-dimensional bi-gravity model derived from New Massive Gravity by making an auxiliary field dynamical, demonstrating its stability and positive central charges, indicating potential consistency.

Contribution

It constructs a novel 3D bi-gravity model from NMG by promoting an auxiliary field to a dynamical one, analyzing its stability and dual CFT properties.

Findings

Fluctuations around AdS are non-tachyonic and ghost free within certain parameters.

Central charges of the dual CFT are positive in the stable parameter range.

The model may represent a consistent 3D bi-gravity theory.

Abstract

Using the action of three dimensional New Massive Gravity (NMG) we construct a new bi-gravity in three dimensions. This can be done by promoting the rank two auxiliary field appearing in the expression of NMG's action into a dynamical field. We show that small fluctuations around the AdS vacuum of the model are non-tachyonic and ghost free within certain range of the parameters of the model. We study central charges of the dual field theory and observe that in this range they are positive too. This suggests that the proposed model might be a consistent three dimensional bi-gravity.