Superradiance Of Anabal(?)n-Astefanesei-Mann Black Holes

The Einstein-Maxwell-dilaton(EMD)theory,which originated from string theory,is one of modified gravitational theories that contains the most types of bosons.It can unify the interaction among gravitational field,electromagnetic field and scalar field.Anabal(?)nAstefanesei-Mann(AAM)black hole is the main black hole of EMD theory.When AAM black hole is disturbed by gravitational wave,dilaton will leave obvious mark in the signal of gravitational wave.Because dilaton changes the space-time structure,we study the influence of dilaton on the scattering process when the charged massive scalar field is scattered by the AAM black hole.In chapter 2,we first introduce the theoretical basis of superradiance in curved spacetime,and derive the relationship among the incident coefficient I,transmitted coefficient T and reflected coefficient R.Then,according to the relationship among three coefficients,we analyzed the superradiant condition when charged massive scalar field is scattered by the Reissner-Nordstr?m(RN)black hole.Finally,for same scalar field’s mass,we compute the superradiant amplification factors corresponding to different charges of black hole and scalar field.In chapter 3,we study the motion’s equation of the charged massive scalar field in the spacetime of AAM black hole.We first introduce the specific form of EMD gravity theory,and sort out the types of black holes in the theory.Then,we introduce the solution of AAM black hole with coupling constant γ = 1,and determine the range of black hole’s charges corresponding to different parameters α.Finally,we derive the radial motion’s equation of the charged massive scalar field in the space-time of AAM black hole.In chapter 4,we first study superradiance when charged massive scalar field is scattered by the AAM black hole.We find that superradiant amplification factors increases with the increase of parameter α.Then,we compute the differential scattering cross section of charged massive field.We find that the width of interference fringes increases with the increase of parameter α.With the increase of parameter α,the values of wave crest and wave trough also increase.Finally,we compute the absorption cross section of charged massive scalar field.We compute the absorption cross section of scalar field and find that the absorption cross section decreases with the increase of parameter α.When superradiance occurs,the absorption cross section of charged scalar field with mass is negative.When superradiance occurs,the absorption cross section of charged massive scalar field is negative.