Chern-Simons-like formulation of 3D MMG-like massive gravity models
Büşra Dedeoğlu, Mehmet Ozkan, Özgür Sarıoğlu
TL;DR
This work addresses constructing a CS‑like, third‑way consistent family of 3D massive gravity models extending MMG and analyzes the simplest non‑trivial case (N=2). Using a torsionful CS‑like Lagrangian with an auxiliary hierarchy, they solve the field equations, obtain AdS$_3$ backgrounds, and compute the central charges $c^{3}$; linearization reveals two massless and three massive modes governed by a cubic mass polynomial. Along the chiral line a rank‑2 Jordan block appears, signaling logarithmic CFT behavior, while at a degenerate point a rank‑3 Jordan form yields two logarithmic partners and an ultra‑logarithmic boundary sector. The results show that unitary, tachyon‑free regimes compete with ghost or tachyonic modes in this class and motivate extending the analysis to higher‑$N$ and to supersymmetric or higher‑spin generalizations.
Abstract
We investigate the Chern-Simons-like formulation of 3D MMG-like massive gravity models that are "third-way consistent". Building on previous work on exotic massive gravities, we analyze a class of MMG-like theories characterized by a specific parity structure and an auxiliary field hierarchy. Focusing on the simplest non-trivial case, we solve the full set of field equations, determine the AdS background solutions, compute the central charges of the dual CFT, and perform a linearized analysis to obtain the mass spectrum. Along the chiral line, the linearized mass operator develops a rank-2 Jordan block, signaling logarithmic behavior of massive modes in the dual two-dimensional CFT. At a special degenerate point, this structure is enhanced to a rank-3 Jordan block, giving rise to two logarithmic partners and an ultra-logarithmic sector in the boundary theory.
