Rotating $(2+1)$-dimensional Black Holes in Einstein-Maxwell-Dilaton Theory

TL;DR

This paper derives new exact rotating black hole solutions in (2+1)-dimensional Einstein-Maxwell-Dilaton theory, showing how the dilaton coupling influences black hole properties and thermodynamics, with potential higher entropy than BTZ black holes.

Contribution

It introduces novel rotating black hole solutions in (2+1)D Einstein-Maxwell-Dilaton theory with explicit dilaton coupling effects.

Findings

Dilatonic black holes can have higher entropy than BTZ black holes.

The dilatonic parameter affects the black hole's thermodynamics and rotation.

The solutions generalize BTZ black holes by including scalar field effects.

Abstract

We consider Einstein-Maxwell-Dilaton theory in $(2+1)$-dimensions where the coupling between the scalar field and the Maxwell invariant is the dilatonic coupling $f(\phi) = \exp (-2\alpha \phi)$ and obtain novel exact rotating black hole solutions. The dilatonic parameter $\alpha$ impacts the metric function, affecting the rotating properties of the black hole, its mass and also its thermodynamics. Calculating the entropy we find that it is always positive and the dilatonic black holes may have higher entropy than the BTZ black hole. Depending on the parameters, the dilatonic BTZ-like black hole may be thermodynamically preferred than the BTZ black hole which is recovered when $\alpha=0$.