Shaping black holes with free fields

TL;DR

This paper constructs new static black hole solutions with matter fields like scalar and p-form fields, exploring their properties and regularization effects, including in higher dimensions and with cosmological constant.

Contribution

It introduces a metric Ansatz allowing matter fields in black hole solutions, including multiple p-forms and axionic fields, expanding the landscape of known black hole configurations.

Findings

Multiple p-form fields enable higher-dimensional dyonic black holes.

Axionic fields can regularize small mass black holes.

Solutions include black holes with Einstein-Kaehler horizons and cosmological constant.

Abstract

Starting from a metric Ansatz permitting a weak version of Birkhoff's theorem we find static black hole solutions including matter in the form of free scalar and p-form fields, with and without a cosmological constant \Lambda. Single p-form matter fields permit multiple possibilities, including dyonic solutions, self-dual instantons and metrics with Einstein-Kaelher horizons. The inclusion of multiple p-forms on the other hand, arranged in a homogeneous fashion with respect to the horizon geometry, permits the construction of higher dimensional dyonic p-form black holes and four dimensional axionic black holes with flat horizons, when \Lambda<0. It is found that axionic fields regularize black hole solutions in the sense, for example, of permitting regular -- rather than singular -- small mass Reissner-Nordstrom type black holes. Their cosmic string and Vaidya versions are also obtained.