Time dependent black holes and gravitational wave in Einstein-Gauss-Bonnet theory with two scalar fields

TL;DR

This paper studies dynamic black holes and gravitational wave propagation in Einstein-Gauss-Bonnet theory with two scalar fields, highlighting how coupling variations affect wave speed and black hole formation.

Contribution

It introduces models of time-dependent black holes in Einstein-Gauss-Bonnet theory with scalar fields and analyzes gravitational wave speed variations due to coupling changes.

Findings

Gravitational wave speed is affected by Gauss-Bonnet coupling.

Ghost modes can be eliminated with specific constraints.

Wave speed varies as waves enter and exit black holes.

Abstract

This paper explores time-varying black holes within the framework of the Einstein-Gauss-Bonnet theory with two scalar fields, examining the propagation of gravitational waves (GW). In reconstructed models, ghosts frequently emerge but can be eliminated by applying certain constraints. We investigate the behavior of high-frequency gravitational waves by examining the effects of varying Gauss-Bonnet coupling during their propagation. The speed of transmission is altered by the coupling in the creation of black holes. The speed of gravitational waves varies as they enter a black hole compared to when they exit.