Publication: Scattering and absorption of a scalar field impinging on a charged black hole in the Einstein-Maxwell-dilaton theory
Дата
2022
Авторы
Richarte, M. G.
Martins, E. L.
Fabris, J. C.
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Аннотация
© 2022 American Physical Society.This study revisits the absorption and scattering process by which a massless scalar field impinges on a charged-dilatonic black hole. First, we review the classical analysis to obtain the deflection angle and the differential scattering cross section in terms of the mass, electric charge and dilatonic charge. Then, using the partial wave method, we determine the total absorption cross section numerically in terms of the decoupling parameter called Mω, finding that the amplitude of the dilatonic black hole is lower than the Reissner-Nordström one for mild frequencies. In the high-frequency limit, the absorption cross section exhibits two different complex behaviors; the fine structure and the hyperfine structure. For the differential scattering cross section, smaller values of Mω lead to more significant amplitudes; the opposite scenario is obtained by increasing the charge-to-mass ratio. To fully grasp the main properties of the charged dilatonic black hole, we consider a different framework where the compact object is impinged by a charged massive scalar field. The superradiant effect is lessened for intermediate frequency concerning the Reissner-Nordström case. However, this effect does not necessarily imply the existence of any dynamical instability. In order to trigger the superradiant instability, unstable modes must remain trapped outside the event horizon with a mechanism based on the reflecting-mirror boundary conditions. In this way, a charged scalar field plus a charged black hole configure a charged black hole bomb. We provide an analytic formula (lower bound) for the values of the charge field, which can trigger this superradiant instability. We extend this minimal setup by considering the dilaton perturbations while freezing the other degree of freedom. The new perturbation scheme enhances the superradiance scattering and reduces the lower bound of the charge-to-mass ratio to develop a superradiant instability.
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Richarte, M. G. Scattering and absorption of a scalar field impinging on a charged black hole in the Einstein-Maxwell-dilaton theory / Richarte, M.G., Martins, E.L., Fabris, J.C. // Physical Review D. - 2022. - 105. - № 6. - 10.1103/PhysRevD.105.064043
URI
https://www.doi.org/10.1103/PhysRevD.105.064043
https://www.scopus.com/record/display.uri?eid=2-s2.0-85128282243&origin=resultslist
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=WOS_CPL&DestLinkType=FullRecord&UT=WOS:000785794800004
https://openrepository.mephi.ru/handle/123456789/29025
https://www.scopus.com/record/display.uri?eid=2-s2.0-85128282243&origin=resultslist
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=WOS_CPL&DestLinkType=FullRecord&UT=WOS:000785794800004
https://openrepository.mephi.ru/handle/123456789/29025