Black holes and asymptotics of 2+1 gravity coupled to a scalar field

TL;DR

This paper explores 2+1 dimensional gravity coupled with a scalar field, revealing that the asymptotic symmetry remains conformal, and introduces new massive black hole solutions with scalar hair.

Contribution

It demonstrates that the asymptotic symmetry group is preserved in scalar-coupled gravity and presents novel black hole solutions with scalar fields.

Findings

Asymptotic symmetry group remains conformal.

New massive black hole solutions with scalar hair.

Black holes connect continuously to zero mass solutions.

Abstract

We consider 2+1 gravity minimally coupled to a self-interacting scalar field. The case in which the fall-off of the fields at infinity is slower than that of a localized distribution of matter is analyzed. It is found that the asymptotic symmetry group remains the same as in pure gravity (i.e., the conformal group). The generators of the asymptotic symmetries, however, acquire a contribution from the scalar field, but the algebra of the canonical generators possesses the standard central extension. In this context, new massive black hole solutions with a regular scalar field are found for a one-parameter family of potentials. These black holes are continuously connected to the standard zero mass black hole.