Dilatonic dyon black hole solutions

Abstract

Dilatonic black hole dyon solutions with arbitrary dilatonic coupling constant $\lambda \ne 0$ and canonical sign $\epsilon =+1$ for scalar field kynetic term are considered. These solutions are defined up to solutions of two master equations for moduli funtions. For ${\lambda }^2\ne 1/2$ the solutions are extended to $\epsilon =\pm 1$, where $\epsilon =-1$ corresponds to ghost (phantom) scalar field. Some physical parameters of the solutions: gravitational mass, scalar charge, Hawking temperature, black hole area entropy and parametrized post-Newtonian (PPN) parameters $\beta$ and $\gamma$ are obtained. It is shown that PPN parameters do not depend on scalar field coupling $\lambda$ and $\epsilon$. Two group of bounds on gravitational mass and scalar charge (for fixed and arbitrary extremality parameter $\mu >0$) are found by using a certain conjecture on parameters of solutions when $1+2{\lambda }^2\epsilon >0$. These bounds are verified numerically for certain examples. By product we are led to well-known lower bound on mass which was obtained earlier by Gibbons, Kastor, London, Townsend and Traschen by using spinor techniques.

20 pages, 2 figures, 2 tables, Latex. Revised version: 6 refs., 3 remarks, a paragraph in Conclusion and several sentences or phrases are added; in Sect. 5 numerics are replaced to the end

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• The Confrontation between General Relativity and Experiment
• Three Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Polarization Analysis
• Phantom Black Holes in Einstein-Maxwell-Dilaton Theory
• Phantom Black Holes and Sigma Models
• "Triangular" extremal dilatonic dyons