Scattering of massless scalar field by charged dilatonic black holes

Abstract

Wave propagations in the presence of black holes is a significant problem both in theoretical and observational aspects, especially after the discovery of gravitational wave and confirmation of black holes. We study the scattering of massless scalar field by a charged dilatonic black hole in frame of full wave theory. We apply partial wave method to obtain the scattering cross sections of the scalar field, and investigate how the black hole charge affects the scalar scattering cross sections. Furthermore, we investigate the Regge pole approach of the scattering cross section of the dilatonic black hole. We find that in order to obtain results at the same precision, we need more Regge poles as the black hole charge increases. We compare the results in the full wave theory and results in the classical geodesic scattering and the semi-classical glory approximations, and demonstrate the improvements and power of our approach.

Scattering and absorption of a scalar field impinging on a charged black hole in the Einstein-Maxwell-dilaton theory

“…In Sec. VIA, the reflection coefficient is obtained, finding that there is a superradiant phenomenon and extending previous results on the literature [36], [43], [44]. In Sec.…”

“…These facts motivate the exploration of both the process of scattering and absorption of massless scalar wave by a charged dilaton black hole, extending previous analysis [36]. In Sec.…”

“…In this section we will determine the absorption differential cross-section working within the short-wavelength approximation (λ r h ), so it is sufficient to visualize plane waves as rays associated with the null geodesics [36]. To do so, we begin by exploring the behavior of null geodesic in terms of the impact parameter.…”

“…Consequently, the photon which is scattered by the compact object and goes back to infinity has an angle of deflection [36] given by…”

“…Since these seminal works, the typical pattern produced by the scattering of wave with a black hole has been used as a powerful tool to extract properties of black hole. The scattering/absorption process of wave by a black hole was examined in the case a canonical acoustic black hole [31], a charged black hole [32], [33], dirty black holes [34], Kerr black holes [35], charged dilatonic black hole [36], and for black hole in Hovara-Lifshitz gravity [37]. The absorption of s-waves by a remanent black hole within in metric-affine gravity was explored by Delhom et al [38].…”