TY - JOUR
T1 - Superradiance around rotating dilatonic black holes
AU - Koga, Jun ichirou
AU - Maeda, Kei ichi
N1 - Funding Information:
We would like to thank T. Tachizawa for useful discussions. This work was supported partially by the Grant-in-Aid for Scientific ResearchF und of the Ministry of Education, Science and Culture (No. 06302021 and No. 06640412)) and by Waseda University Grant for Special ResearchP rojects.
PY - 1994/12/1
Y1 - 1994/12/1
N2 - 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.
AB - 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.
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U2 - 10.1016/0370-2693(94)91293-9
DO - 10.1016/0370-2693(94)91293-9
M3 - Article
AN - SCOPUS:0040331316
SN - 0370-2693
VL - 340
SP - 29
EP - 34
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
IS - 1-2
ER -