Asymptotically (A)dS dilaton black holes with nonlinear electrodynamics (1801.05697v1)

Abstract: It is well-known that with an appropriate combination of three Liouville-type dilaton potentials, one can construct charged dilaton black holes in an (anti)-de Sitter [(A)dS] spaces in the presence of linear Maxwell field. However, asymptotically (A)dS dilaton black holes coupled to nonlinear gauge field have not been found. In this paper, we construct, for the first time, three new classes of dilaton black hole solutions in the presence of three types of nonlinear electrodynamics, namely Born-Infeld, Logarithmic and Exponential nonlinear electrodynamics. All these solutions are asymptotically (A)dS and in the linear regime reduce to the Einstein-Maxwell-dilaton black holes in AdS spaces. We investigate physical properties and the causal structure, as well as asymptotic behavior of the obtained solutions, and show that depending on the values of the metric parameters, the singularity can be covered by various horizons. Interestingly enough, we find that the coupling of dilaton field and nonlinear gauge field in the background of (A)dS spaces leads to a strange behaviour for the electric field. We observe that the electric field is zero at singularity and increases smoothly until reaches a maximum value, then it decreases smoothly until goes to zero as $r\rightarrow\infty$. The maximum value of the electric field increases with increasing the nonlinear parameter $\beta$ or decreasing the dilaton coupling $\alpha$ and is shifted to the singularity in the absence of either dilaton field ($\alpha=0$) or nonlinear gauge field ($\beta\rightarrow\infty$).