Gyromagnetic Ratio of Charged Kerr-Anti-de Sitter Black Holes

TL;DR

This paper investigates the gyromagnetic ratios of charged Kerr-AdS black holes across various dimensions, revealing a universal value of g=2 at critical rotation, and confirms these findings in five-dimensional supergravity solutions.

Contribution

It provides the first comprehensive calculation of gyromagnetic ratios for Kerr-AdS black holes in multiple dimensions, including exact solutions in supergravity, highlighting universal behaviors.

Findings

Gyromagnetic ratio g=2 at critical rotation in all dimensions.

Gyromagnetic ratio remains unchanged in five-dimensional supergravity black holes.

The ratio depends on the rotation parameter and AdS curvature radius.

Abstract

We examine the gyromagnetic ratios of rotating and charged AdS black holes in four and higher spacetime dimensions. We compute the gyromagnetic ratio for Kerr-AdS black holes with an arbitrary electric charge in four dimensions and show that it corresponds to g=2 irrespective of the AdS nature of the spacetime. We also compute the gyromagnetic ratio for Kerr-AdS black holes with a single angular momentum and with a test electric charge in all higher dimensions. The gyromagnetic ratio crucially depends on the dimensionless ratio of the rotation parameter to the curvature radius of the AdS background. At the critical limit, when the boundary Einstein universe is rotating at the speed of light, it exhibits a striking feature leading to g=2 regardless of the spacetime dimension. Next, we extend our consideration to include the exact metric for five-dimensional rotating charged black holes in minimal gauged supergravity. We show that the value of the gyromagnetic ratio found in the "test-charge" approach remains unchanged for these black holes.