Greybody factors for a spherically symmetric Einstein-Gauss-Bonnet–de Sitter black hole

Abstract

We study the greybody factors of the scalar fields in spherically symmetric Einstein-Gauss-Bonnet-de Sitter black holes in higher dimensions. We derive the greybody factors analytically for both minimally and non-minimally coupled scalar fields. Moreover, we discuss the dependence of the greybody factor on various parameters including the angular momentum number, the non-minimally coupling constant, the spacetime dimension, the cosmological constant and the Gauss-Bonnet coefficient in detail. We find that the non-minimal coupling may suppress the greybody factor and the Gauss-Bonnet coupling could enhance it, but they both suppress the energy emission rate of Hawking radiation. *

Black hole evaporation in Lovelock gravity with diverse dimensions

“…Furthermore, we apply the geometrical optics approximation and assume the emitted massless quanta move along null geodesics. However, to get a precise lifetime one has to compute the grey body factors of all the particles [46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63]. On the other hand, near the end of the evaporation, effective field theory starts to fail, and quantum gravity effect may stop the evaporation, leaving a black hole "remnant" [64][65][66][67].…”

Hawking radiation for scalar fields by Einstein-Gauss-Bonnet–de Sitter black holes

“…To get the information of the Hawking radiation, such as the greybody factor and power spectra of the scalar field, one should solve the radial equation (7) at first. In [40], by solving (7) near the event horizon and cosmological horizon separately and matching them in the intermediate region, they derived an approximatively analytical formula for the greybody factors when the cosmological constant and nonminimal coupling constant of the filed are small. Though it is valid for all partial modes and may hold beyond the low energy regime, the deviation in the high energy regime is obvious.…”

“…Here we would like to mention that a new approximate method was adopted to obtain the analytic expressions for the greybody factors of nonminimally scalar fields by a higher dimensional Schwarzschild-dS (SdS) black hole [19]. By using the same method the study was extended to the case of EGB-dS black holes in [40]. The properties of the greybody factors and power spectra of Hawking radiation in terms of the particle and spacetime parameters were analyzed in detail.…”

“…The potential vanishes at both the event horizon and cosmological horizon of EGB-dS black hole, which allows us to analytically derive the greybody factor by using matched asymptotic expansion method [40]. In the intermediate region of these two horizons, the potential has the form of a barrier.…”

“…In the intermediate region of these two horizons, the potential has the form of a barrier. In [40] it was revealed that due to the presence of the GB coupling constantα, the dependence of the profile of the barrier on both spacetime and particle parameters becomes more subtle. For example, withoutα the height of the barrier increase with the coupling parameter ξ of the scalar field, however, whenα has a large nonzero value, ξ suppresses the barrier.…”