Higher-Derivative Corrected Black Holes: Perturbative Stability and Absorption Cross-Section in Heterotic String Theory

TL;DR

This paper investigates the stability and absorption properties of higher-derivative corrected black holes in heterotic string theory, demonstrating their perturbative stability and analyzing how stringy corrections affect their scattering characteristics.

Contribution

It develops a perturbation framework for higher-derivative corrected black holes, proves their stability in any dimension, and computes  corrections to the absorption cross-section.

Findings

Black holes are perturbatively stable in any dimension.

 corrections modify the absorption cross-section, but it remains proportional to the horizon area.

Proposed an expression for the absorption cross-section valid to all orders in .

Abstract

This work addresses spherically symmetric, static black holes in higher-derivative stringy gravity. We focus on the curvature-squared correction to the Einstein-Hilbert action, present in both heterotic and bosonic string theory. The string theory low-energy effective action necessarily describes both a graviton and a dilaton, and we concentrate on the Callan-Myers-Perry solution in d-dimensions, describing stringy corrections to the Schwarzschild geometry. We develop the perturbation theory for the higher-derivative corrected action, along the guidelines of the Ishibashi-Kodama framework, focusing on tensor type gravitational perturbations. The potential obtained allows us to address the perturbative stability of the black hole solution, where we prove stability in any dimension. The equation describing gravitational perturbations to the Callan-Myers-Perry geometry also allows for a study of greybody factors and quasinormal frequencies. We address gravitational scattering at low frequencies, computing corrections arising from the curvature-squared term in the stringy action. We find that the absorption cross-section receives \alpha' corrections, even though it is still proportional to the area of the black hole event-horizon. We also suggest an expression for the absorption cross-section which could be valid to all orders in \alpha'.