Macroscopic and Microscopic Description of Black Diholes

TL;DR

This paper presents exact solutions for pairs of non-extremal black holes with opposite charges in four-dimensional Einstein-Maxwell and string theory contexts, analyzing their physical properties and providing a microscopic entropy description.

Contribution

It introduces new exact solutions for diholes with opposite charges and offers a microscopic entropy model considering string interactions.

Findings

Physical properties like area and charge have simple expressions.

Exact solutions are obtained for Einstein-Maxwell and string theories.

Microscopic entropy matches macroscopic calculations.

Abstract

We study configurations consisting of a pair of non-extremal black holes in four dimensions, both with the same mass, and with charges of the same magnitude but opposite sign---diholes, for short. We present such exact solutions for Einstein-Maxwell theory with arbitrary dilaton coupling, and also solutions to the U(1)^4 theories that arise from compactified string/M-theory. Despite the fact that the solutions are very complicated, physical properties of these black holes, such as their area, charge, and interaction energy, admit simple expressions. We also succeed in providing a microscopic description of the entropy of these black holes using the `effective string' model, and taking into account the interaction between the effective string and anti-string.