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Register a new userSuperradiance and stability of the novel 4D charged Einstein-Gauss-Bonnet black hole
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We investigated the superradiance and stability of the novel 4D charged Einstein-Gauss-Bonnet black hole which is recently inspired by Glavan and Lin [Phys. Rev. Lett. 124, 081301 (2020)]. We found that the positive Gauss-Bonnet coupling consant $alpha$ enhances the superradiance, while the negative $alpha$ suppresses it. The condition for superradiant instability is proved. We also worked out the quasinormal modes (QNMs) of the charged Einstein-Gauss-Bonnet black hole and found that the real part of all the QNMs live beyond the superradiance condition and the imaginary parts are all negative. Therefore this black hole is superradiant stable. When $alpha$ makes the black hole extremal, there are normal modes.
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We study the charge of the 4D-Einstein-Gauss-Bonnet black hole by a negative charge and a positive charge of a particle-antiparticle pair on the horizons r- and r+, respectively. We show that there are two types of the Schwarzschild black hole. We show also that the Einstein-Gauss-Bonnet black hole charge has quantified values. We obtain the Hawking-Bekenstein formula with two logarithmic corrections, the second correction depends on the cosmological constant and the black hole charge. Finally, we study the thermodynamics of the EGB-AdS black hole.
In this paper, we investigate the four-dimensional Einstein-Gauss-Bonnet black hole. The thermodynamic variables and equations of state of black holes are obtained in terms of a new parameterization. We discuss a formulation of the van der Waals equation by studying the effects of the temperature on P-V isotherms. We show the influence of the Cauchy horizon on the thermodynamic parameters. We prove by different methods, that the black hole entropy obey area law (plus logarithmic term that depends on the Gauss-Bonnet coupling {alpha}). We propose a physical meaning for the logarithmic correction to the area law. This work can be extended to the extremal EGB black hole, in that case, we study the relationship between compressibility factor, specific heat and the coupling {alpha}.
We have investigated tidal forces and geodesic deviation motion in the 4D-Einstein-Gauss-Bonnet spacetime. Our results show that tidal force and geodesic deviation motion depend sharply on the sign of Gauss-Bonnet coupling constant. Comparing with Schwarzschild spacetime, the strength of tidal force becomes stronger for the negative Gauss-Bonnet coupling constant, but is weaker for the positive one. Moreover, tidal force behaves like those in the Schwarzschild spacetime as the coupling constant is negative, and like those in Reissner-Nordstr{o}m black hole as the constant is positive. We also present the change of geodesic deviation vector with Gauss-Bonnet coupling constant under two kinds of initial conditions.
We study the linear instability of the charged massless scalar perturbation in regularized 4D charged Einstein-Gauss-Bonnet-AdS black holes by exploring the quasinormal modes. We find that the linear instability is triggered by superradiance. The charged massless scalar perturbation becomes more unstable when increasing the Gauss-Bonnet coupling constant or the black hole charge. Meanwhile, decreasing} the AdS radius will make the charged massless scalar perturbation} more stable. The stable region in parameter space $(alpha,Q,Lambda)$ is given. Moreover, we find that the charged massless scalar perturbation is more unstable for larger scalar charge. The modes of multipoles are more stable than that of the monopole.
In this work we study the properties of compact spheres made of a charged perfect fluid with a MIT bag model EoS for quark matter. Considering static spherically symmetric spacetime we derive the hydrostatic equilibrium equations in the recently formulated four dimensional Einstein-Gauss-Bonnet ($4D$ EGB) gravity theory. In this setting, the modified TOV equations are solved numerically with the aim to investigate the impact of electric charge on the stellar structure. A nice feature of $4D$ EGB theory is that the Gauss-Bonnet term has a non-vanishing contribution to the gravitational dynamics in $4D$ spacetime. We therefore analyse the effects of Gauss-Bonnet coupling constant $alpha$ and the charge fraction $beta$ on the mass-radius ($M-R$) diagram and also the mass-central density $(M-rho_c)$ relation of quark stars. Finally, we conclude that depending on the choice of coupling constant one could have larger mass and radius compared with GR and can also be relevant for more massive compact objects due to the effect of the repulsive Coulomb force.
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