Asymptotically flat black holes sourced by a massless scalar field

TL;DR

This paper presents exact asymptotically flat black hole solutions in Einstein-scalar gravity with a non-trivial scalar field, analyzing their properties and thermodynamics, and comparing them to Schwarzschild black holes.

Contribution

It introduces new exact black hole solutions sourced by a scalar field with specific asymptotic behavior and explores their thermodynamics, expanding understanding of scalar-hairy black holes.

Findings

Black holes with scalar hair have similar thermodynamics to Schwarzschild at large mass.

At small mass, these black holes show significant thermodynamic differences.

The solutions include a detailed scalar potential consistent with the scalar profile.

Abstract

We derive exact, asymptotically flat black hole solutions of Einstein-scalar gravity sourced by a non trivial scalar field with $1/r$ asymptotic behaviour. They are determined using an ansatz for the scalar field profile and working out, together with the metric functions, the corresponding form of the scalar self-interaction potential. Near to the singularity the black hole behaves as the Janis-Newmann-Winicour-Wyman solution. We also work out a consistent thermodynamical description of our black hole solutions. For large mass our hairy black holes have the same thermodynamical behaviour of the Schwarzschild black hole, whereas for small masses they differ substantially from the latter.