Superradiance around Rotating Dilatonic Black Hole

Abstract

We consider a superradiance effect around rotating dilatonic black holes. We analyze two cases: one is an exact solution with the coupling constant $\alpha =\sqrt{3}$, which effective action is reduced from the 5-dimensional Kaluza-Klein theory, and the other is a slowly rotating dilatonic black holes with arbitrary coupling constant. We find that there exists a critical value ($\alpha \sim 1$), which is predicted from a superstring model, and the superradiant emission rate with coupling larger than the critical value becomes much higher than the Kerr-Newman case ($\alpha =0$) in the maximally charged limit. Consequently, 4-dimensional primordial black holes in higher dimensional unified theories are either rotating but almost neutral or charged but effectively non-rotating.

12 pages, Latex, three figures, WU-AP/43/94

References in corpus (4)

• Black Holes as Elementary Particles
• Rotating Dilaton Black Holes
• Spinning a charged dilaton black hole
• Superradiance from a Charged Dilaton Black Hole

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