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arXiv · hep-th/9408084

Superradiance around Rotating Dilatonic Black Hole

Jun-ichirou Koga·Kei-ichi Maeda
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Abstract

We consider a superradiance effect around rotating dilatonic black holes. We analyze two cases: one is an exact solution with the coupling constant $α=\sqrt{3}$, 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 ($α\sim 1$), 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 ($α=0$) 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.

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Jun-ichirou Koga, Kei-ichi Maeda. 1994-08-16. Superradiance around Rotating Dilatonic Black Hole. https://doi.org/10.1016/0370-2693(94)91293-9

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