Slowly rotating black hole solution to Einstein-Bel-Robinson gravity

TL;DR

This paper investigates slowly rotating black hole solutions in Einstein-Bel-Robinson gravity, analyzing their physical properties and superradiance phenomena to understand modifications due to rotation and higher-curvature effects.

Contribution

It provides approximate solutions for slowly rotating black holes in EBR gravity and explores their physical characteristics and superradiance behavior at leading order.

Findings

Rotation introduces a non-zero g_{t} component.

Black hole properties like photon sphere and shadow are modified.

Superradiance conditions depend on rotation and wave frequency.

Abstract

We study slowly rotating black hole solutions in the Einstein-Bel-Robinson gravity (EBR) in four dimensions. At the leading order in the rotation parameter, the only modification with respect to the static case is the appearance of a non-vanishing $g_{t\phi}$ component. We construct approximate solutions to these equations and study how physical properties of the solutions, such as the angular velocity, photon sphere, black hole shadow, and innermost stable circular orbit, are modified, working to leading order in the coupling constant and the rotation parameter. Finally, we study the superradiance of a massive scalar wave scattering off slowly rotating black holes. Using direct integration, we derive the superradiant conditions and compute the energy flux through the event horizon and amplification factor. We demonstrate how the flux and amplification factor will change as a function of the black hole rotation and frequency of the incident wave.