Black hole initial data in Gauss-Bonnet gravity: Momentarily static case

TL;DR

This paper develops a numerical method to generate initial data for black hole systems in Gauss-Bonnet gravity, enabling future simulations of black hole collisions in higher-curvature theories.

Contribution

It introduces a successful numerical relaxation approach to solve the nonlinear conformal factor equation for black hole initial data in Gauss-Bonnet gravity, including multi-black-hole systems.

Findings

The conformal factor equation is solvable numerically despite nonlinearity.

The apparent horizon analysis suggests Penrose inequalities hold in this setup.

This work paves the way for simulating black hole collisions in higher-curvature theories.

Abstract

We study the method for generating the initial data of black hole systems in Gauss-Bonnet (GB) gravity. The initial data are assumed to be momentarily static and conformally flat. Although the equation for the conformal factor is highly nonlinear, it is successfully solved by numerical relaxation for one-black-hole and two-black-hole systems. The common apparent horizon is studied in the two-black-hole initial data, and the result suggests that the Penrose inequalities are satisfied in this system. This is the first step for simulating black hole collisions in higher-curvature theories.