A remarkably simple theory of 3d massive gravity

Understand

We propose and study a new action for three-dimensional massive gravity.

• This action takes a very simple form when written in terms of connection and triad variables, but the connection can also be integrated out to obtain a triad formulation.
• The quadratic action for the perturbations around a Minkowski background reproduces the action of self-dual massive gravity, in agreement with the expectation that the theory propagates a massive graviton.
• We confirm this result at the non-linear level with a Hamiltonian analysis, and show that this new theory does indeed possess a single massive degree of freedom.