Holographic studies of Einsteinian cubic gravity

TL;DR

This paper explores Einsteinian cubic gravity as a holographic model for a three-dimensional CFT, providing exact solutions, thermodynamic analysis, and new insights into entanglement and transport properties, with a novel method for on-shell action evaluation.

Contribution

It introduces a new approach for calculating Euclidean on-shell actions in higher-order gravities and applies it to Einsteinian cubic gravity, revealing detailed holographic dictionary entries and physical phenomena.

Findings

Explicit non-hairy AdS4 black holes in Einsteinian cubic gravity

Non-perturbative calculations of thermodynamics and phase space

Dependence of Rènyi entropies on universal CFT quantities

Abstract

Einsteinian cubic gravity provides a holographic toy model of a nonsupersymmetric CFT in three dimensions, analogous to the one defined by Quasi-topological gravity in four. The theory admits explicit non-hairy AdS$_4$ black holes and allows for numerous exact calculations, fully nonperturbative in the new coupling. We identify several entries of the AdS/CFT dictionary for this theory, and study its thermodynamic phase space, finding interesting new phenomena. We also analyze the dependence of R\'enyi entropies for disk regions on universal quantities characterizing the CFT. In addition, we show that $\eta/s$ is given by a non-analytic function of the ECG coupling, and that the existence of positive-energy black holes strictly forbids violations of the KSS bound. Along the way, we introduce a new method for evaluating Euclidean on-shell actions for general higher-order gravities possessing second-order linearized equations on AdS$_{(d+1)}$. Our generalized action involves the very same Gibbons-Hawking boundary term and counterterms valid for Einstein gravity, which now appear weighted by the universal charge $a^*$ controlling the entanglement entropy across a spherical region in the CFT dual to the corresponding higher-order theory.