Exact results for evaporating black holes in curvature-squared Lovelock gravity: Gauss-Bonnet greybody factors

Abstract

Lovelock gravity is an important extension of general relativity that provides a promising framework to study curvature corrections to the Einstein action, while avoiding ghosts and keeping second order field equations. This paper derives the greybody factors for $D$-dimensional black holes arising in a theory with a Gauss-Bonnet curvature-squared term. These factors describe the nontrivial coupling between black holes and quantum fields during the evaporation process: they can be used both from a theoretical viewpoint to investigate the intricate space-time structure around such a black hole, and for phenomenological purposes in the framework of braneworld models with a low Planck scale. We derive exact spectra for the emission of scalar, fermion and gauge fields emitted on the brane, and for scalar fields emitted in the bulk, and demonstrate how the Gauss-Bonnet term can change the bulk-to-brane emission rates ratio in favor of the bulk channel in particular frequency regimes.