Statistical Description of Rotating Kaluza-Klein Black Holes

TL;DR

This paper extends the microscopic analysis of extremal Kaluza-Klein black holes to include fast rotation, revealing how their entropy, mass, and ergosphere features align with macroscopic and Kerr black hole properties.

Contribution

It introduces a microscopic model for fast rotating Kaluza-Klein black holes, including ergospheres and superradiance, and connects these to Myers-Perry black holes as a limit.

Findings

Microscopic entropy matches macroscopic results for fast rotation.

Mass renormalization from weak to strong coupling is confirmed.

Ergosphere and superradiance are explained microscopically.

Abstract

We extend the recent microscopic analysis of extremal dyonic Kaluza-Klein (D0-D6) black holes to cover the regime of fast rotation in addition to slow rotation. Fastly rotating black holes, in contrast to slow ones, have non-zero angular velocity and possess ergospheres, so they are more similar to the Kerr black hole. The D-brane model reproduces their entropy exactly, but the mass gets renormalized from weak to strong coupling, in agreement with recent macroscopic analyses of rotating attractors. We discuss how the existence of the ergosphere and superradiance manifest themselves within the microscopic model. In addition, we show in full generality how Myers-Perry black holes are obtained as a limit of Kaluza-Klein black holes, and discuss the slow and fast rotation regimes and superradiance in this context.