“Minimal Massive Gravity” (MMG) is a particular extension of Einstein gravity in 3-dimensions with higher curvature terms which propagates a single massive spin-2 mode around an AdS background and is distinguished by the fact that its parameter space allows for a region in which the massive spin-2 mode is neither ghost nor tachyonic, while maintaining both boundary central charges positive. Therefore, remarkably, MMG satisfies both bulk and boundary unitarity simultaneously which most other 3D massive gravity models suffer. However, MMG also has a rather unusual property; its field equation, does not come from the variation of a local action of the metric alone. Consequently, the Bianchi identity on its own does not guarantee the consistency of this equation. Nevertheless, this equation still makes sense on-shell since its divergence vanishes if one uses the field equation again. This novel mechanism is called ”third way consistency”. At the ESI we would like to study supersymmetric solutions of the minimal massive supergravity which was constructed recently. Such solutions are pivotal in the study of supergravity theories since they enjoy stability properties that survive quantum deformations and have various important applications.

Research Team: Nihat Sadik Deger (Bogazici U, Istanbul) and Jan Rosseel (Rudjer Boskovic Institute, Zagreb).