Chiral Topologically Massive Gravity and Extremal B-F Scalars

TL;DR

This paper explores the unique features of chiral topologically massive gravity at a critical coupling, revealing a scalar field description at the Breitenlohner-Freedman bound that explains solution branches and instabilities.

Contribution

It introduces a scalar field parametrization at the critical point, providing new insights into the solution structure and instabilities of chiral topologically massive gravity.

Findings

Emergence of a logarithmic solution branch.

Linearization instability under certain boundary conditions.

Scalar field description at the Breitenlohner-Freedman bound.

Abstract

At a critical ``chiral'' coupling, topologically massive gravity with a negative cosmological constant exhibits several unusual features, including the emergence of a new logarithmic branch of solutions and a linearization instability for certain boundary conditions. I show that at this coupling, the linearized theory may be parametrized by a free scalar field at the Breitenlohner-Freedman bound, and use this description to investigate these features.