Superradiance around rotating dilatonic black holes

Jun ichirou Koga*, Kei ichi Maeda

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


We consider a superradiance effect around rotating dilatonic black holes. We analyze two cases: one is an exact solution with the coupling constant α = 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 ∼ 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.

Original languageEnglish
Pages (from-to)29-34
Number of pages6
JournalPhysics Letters B
Issue number1-2
Publication statusPublished - 1994 Dec 1

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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