2001 Fiscal Year Final Research Report Summary
Grant-in Aid for Scientific Research c (2)
| Project/Area Number |
11640270
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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 |
NAMBU Yasusada Nagoya University graduate school of science, associated prof., 大学院・理学研究科, 助教授 (40212112)
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| Project Period (FY) |
1999 – 2001
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| Keywords | inhomogeneous universe / back reaction / renormalization group / inflationv |
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| Research Abstract |
1 ) For long wavelength expansion of Einstein's equation, we obtained the renormalization group equation that describes non-linear dynamics of the long wave fluctuation. The solution of the renormalization group equation shows that the renormalized metric describes the behavior of the gravitational collapse in the expanding universe qualitatively well.
In modern cosmology, general relativity plays an essential role in explaining the origin and the evolution of our universe. However its basic equation, Einstein's equation, is non-liner partial differential equation and it is difficult to obtain its solution in general. We must use some approximation method or numeral method to investigate problems in general relativity. The purpose of this research is to construct non-linear approximation method for Einstein's equation based on the renormalization group method. The results of this research are
2)We investigate the back reaction of cosmological perturbation on the evolution of the Universe using the renormalization group method. Staring from the second order perturbed Einstein's equation, we renormalize a scale factor of the Universe and derive the evolution equation for the effective scale factor that includes back reaction effect due to inhomogeneities of the Universe.
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