Critical Phenomena in Gravitational Collapse and the Black Hole Evaporation
Project/Area Number  07640390 
Research Category 
GrantinAid for Scientific Research (C)

Allocation Type  Singleyear Grants 
Section  一般 
Research Field 
素粒子・核・宇宙線

Research Institution  Nagoya University 
Principal Investigator 
TOMIMATSU Akira Nagoya University, Department of Physics, Professor, 大学院・理学研究科, 教授 (10034612)

Project Period (FY) 
1995 – 1996

Project Status 
Completed(Fiscal Year 1996)

Budget Amount *help 
¥1,300,000 (Direct Cost : ¥1,300,000)
Fiscal Year 1996 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1995 : ¥700,000 (Direct Cost : ¥700,000)

Keywords  Critical Gravitational Collapse / Quantum Evaporation / Black Hole Physics / Quantum Gravity / General Relativity 
Research Abstract 
Black holes physics has attracted much attention to investigate interesting properties of strong gravity. However, the main depvelopments of the research area have been limited to stationary black holes. This research project is to study in detail dynamical black holes in spherically symmetric gravitational collapse of a massless scalar field, with the purpose of finding new aspects in classical and quantum levels especially in terms of the critical phenomena and the quantum evaporation. 1. For scalar field collapse some critical phenomena in black hole formation occur as a result of the interaction between selfgravity and wave dispersion. By using the selfsimilar model of the critical collapse, the dynamical evolution of field variables is quantized under the canonical formalism, and the wave function of evaporating black hole is explicitly derived. This is the first successful example to show the effect of quantum gravity in black hole dynamics. 2. The classical dynamics of scalar field collapse is more extensively studied, and the massscaling law of nearcritical black holes is found to be due to the generation of an oscillatory mode of scalar fielddisturbing the selfsimilar collapse. The critical exponent of the massscaling law is shown to be determined by the period of the oscillation. The dynamical behavior near the central singularity is also pointed out to be crucial to the black hole mass. 3. A new definition of the surface gravity for dynamical black holes, which gives thermal temperature in quantum evaporation, is proposed. Then, the quantum evaporation shown in the selfsimilar model is claimed to be a nonthermal process. The more extensive models of quantum critical collapse will be investigated in future works to establish such a nonthermal (dynamical) property of evaporating black holes.

Report
(3results)
Research Output
(16results)