New Bi-Gravity from New Massive Garvity

Understand

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.