Vacua of Exotic Massive 3D Gravity

Understand

We consider the recently proposed exotic 3D massive gravity.

• We show that this theory has a rich space of vacua, including asymptotically Anti de-Sitter (AdS) geometries obeying either the standard Brown-Henneaux boundary conditions or the weakened asymptotic behavior of the so-called Log-gravity.
• Both sectors contain non-Einstein spaces with $SO(2)\times \mathbb{R}$ isometry group, showing that the Birkhoff theorem does not hold all over the parameter space, even if strong AdS boundary conditions are imposed.
• Some of these geometries correspond to 3D black holes dressed with a Log-gravity graviton.