Scalar scattering from black holes with tidal charge

TL;DR

This paper investigates how tidal charge in black holes, predicted by the Randall--Sundrum brane-world model, affects scalar wave scattering and absorption, revealing significant near-horizon effects and confirming universality in low-frequency absorption.

Contribution

It provides the first detailed analysis of scalar scattering cross sections for black holes with tidal charge, comparing with Schwarzschild and Reissner--Nordström cases, and confirms universality in low-frequency absorption.

Findings

Tidal charge increases black hole absorption cross section.

Narrowing of interference fringes correlates with tidal charge intensity.

Analytical high-frequency results match numerical partial-wave calculations.

Abstract

The cross sections of black holes with tidal charge predicted in the context of the Randall--Sundrum brane-world scenario are computed considering the massless scalar field. Results obtained for black holes with different tidal-charge intensities are compared in order to study how this charge modifies the black hole cross sections. Such results are also compared with the ones for Schwarzschild and extreme Reissner--Nordstr\"om black holes. The increase of the tidal-charge intensity makes the black hole absorb more and can also be measured by the narrowing of interference fringes of the differential scattering cross section. These results indicate that the effects of the tidal charge are very important in phenomena which take place near the black hole, but can be neglected in the far region. Analytical results are obtained in the high-frequency limit and are shown to excellently agree with the numeric results obtained via the partial-wave method. It is shown numerically that black holes with tidal charge obey the universality of the low-frequency absorption cross section of stationary black holes for the massless scalar field.