2003 Fiscal Year Final Research Report Summary
Dynamics of Massive Fields in Black Hole Spacetimes
| Project/Area Number |
14540253
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | Nagoya University |
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Principal Investigator |
TOMIMATSU Akira Nagoya University, Department of Physics, Professor, 理学研究科, 教授 (10034612)
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| Project Period (FY) |
2002 – 2003
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| Keywords | General Relativity / Black Hole Physics / Wave Equation / Resonance Effect |
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| Research Abstract |
The interesting properties of black holes due to strong gravity have been studied from various viewpoints. In particular, the dynamical evolution of perturbative fields has been one of the fundamental problems in black hole physics. The main purpose of this research project is to find new aspects of the evolutionary behaviors due to the non-zero rest mass of scalar fields around a black hole.
1.First, the late-time tails of massive scalar fields are studied. The field amplitude should decay with the lapse of time, if the fields are radiated away to a distant region. It is found that a resonant backscattering of the radiation can play an important role for the late-time evolution, and in all spherically symmetric black hole spacetimes a universal power-law decay becomes the dominant behavior. This result relied on the analytical Green function technique is verified by numerical calculations done by other research groups. The power-law decay of massive fields is quite slower if compared with the standard decay law established for massless fields and will be useful to check observationally whether the fields are massless or massive.
2.Next, the bound states of charged (massive) scalar fields in Kerr background geometry are investigated, by considering the effect of a uniform magnetic field around the rotating black hole. The superradiant amplification of the fields is found, and interestingly it is shown that the growing rate is crucially dependent on the sign of the field charge. This can be a mechanism to generate a large net charge in the black hole magnetosphere and to trigger electromagnetic burst phenomena.
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