Slowly rotating Einstein-bumblebee black hole solution and its greybody factor in a Lorentz violation model

We obtain an exact slowly rotating Einstein-bumblebee black hole solution by solving the corresponding rr and tθ components of the gravitational field equations for both cases:A)b u=(0,b(r),0,0) and B) bu=(0,b(r),b(θ),0) .Then,we check the other gravitational field equations and the bumblebee field motion equations using this solution.We find that for case A,there indeed exists a slowly rotating black hole solution for an arbitrary LV(Lorentz violation)coupling constant l;however,for case B,this slowly rotating solution exists if and only if coupling constant l is as small as or smaller than angular momentum a.Thus far,no full rotating black hole solution has been published;hence,the Newman-Janis algorithm cannot be used to generate a rotating solution in the Einstein-bumblebee theory.This is similar to the Einstein-aether theory,wherein only some slowly rotating black hole solutions exist.To study the effects of this broken Lorentz symmetry,we consider the black hole greybody factor and find that,for angular index l=0 ,LV constant l decreases the effective potential and enhances the absorption probability,which is similar to the results for the non-minimal derivative coupling theory.

Destroying a Peldan Electrostatic Solution Black Hole

By throwing a particle with electric charge and angular momentum into the black holes, much evidence shows that the naked singularity of some （3＋1）-dimensional black holes might be seen, which is not allowed in the weak cosmic censorship conjecture. In this study, we consider a （2＋1）-dimensional Peldan black hole and find that it could be destroyed under certain conditions in both extreme and near-extreme cases.

Inconsistence of Non-Singular Spherically Symmetric Solution and a Satisfactory Energy-Momentum Complex

Two spherically symmetric non-singular black hole solutions in Moiler tetrad theory of gravitation have been obtained. Although the two solutions have the same form of metric （spherically symmetric nonsingular black hole）, their energy contents are different. We use another method given by Gibbons and Hawking to calculate the energy content of these solutions. We also obtained different value of energy. Study the requirements of a satisfactory energymomentum complex given by Moiler we find that the second solution, which behaves as 1/√r, is not transformed as a four-vector under Lorentz transformation.

Gravitational decoupling for hairy black holes in asymptotic AdS spacetimes

In this study,the gravitational decoupling approach via extended geometric deformation is utilized to generate analytical black hole solutions owing to its simplicity and effectiveness.Considering the external fields surrounding Schwarzschild AdS black holes,we derive hairy black hole solutions in asymptotic AdS spacetime,satisfying the strong and dominant energy conditions.Moreover,we find that if the black hole spacetime is a fluid system,the fluid under each of these conditions is anisotropic.

High dimensional AdS-like black hole and phase transition in Einstein-bumblebee gravity

In this study,we obtained an exact high dimensional anti-de Sitter(AdS)black hole solution in Einsteinbumblebee gravity theory.This AdS-like black hole can only exist with a linear functional potential of the bumblebee field.We found that the Smarr formula and the first law of black hole thermodynamics can still be constructed in this Lorentz symmetry breaking black hole spacetime,but the conceptions of the black hole horizon area/entropy and the volume inside the horizon should be renewed due to its anisotropy.We also found that two types of phase transition exist:small-large black hole phase transition and Hawking-Page phase transition,like those of the Schwarzschild AdS black hole.After Lorentz symmetry breaking,the black hole mass at the divergent point of heat capacity becomes small,and the Gibbs free energy of the meta-stable large black hole is also smaller,showing that the large stable black hole can be more easily formed.

Phantom Dilaton Field and Asymptotic Distribution Parameter in (2+1)-Dimensional Maxwell-Chern-Simons Gravity

The (2+1)-dimensional Maxwell-Chern-Simons gravity with phantom dilaton field coupling is studied in this paper.It is shown that black hole solution to exist when electromagnetic coupled to dilaton field in the non-trivial way.Moreover,asymptotic index and distribution parameter of current density are calculated by using black hole solution,some new features of this solution are briefly discussed.