2003 Fiscal Year Final Research Report Summary
The two-way research on the origin and the evolution of the cosmic structures
| Project/Area Number |
13640285
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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 | Osaka University |
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Principal Investigator |
YOKOYAMA Jun'ichi Osaka University, Graduate School of Science, Associate Professor, 大学院・理学研究科, 助教授 (50212303)
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| Project Period (FY) |
2001 – 2003
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| Keywords | dark matter / dark energy / axion / cosmic microwave background radiation / density fluctuations / inflation / primordial spectrum / cosmological constant |
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| Research Abstract |
The main purpose of this project was to clarify the natures of the two main ingredients of the Universe, namely dark matter and dark energy as well as to establish a theoretical framework to analyze high-precision observational data on cosmic microwave background radiation and the large-scale structure of the Universe in order to obtain useful information to describe the early Universe.
The main achievements are as follows.
1 We performed a high-precision numerical analysis of the evolution of axionic strings and developed a new scheme to analyze it. As a result we succeeded in obtaining the production rate of axions, which is one of the two main candidates of cold dark matter, precisely for the first time.
2 I proposed that the observed tiny amount of dark energy can be easily implemented if we consider theories of degenerate classical vacua and if quantum transition between them is possible through instantons.
3 We developed a method to reconstruct the spectrum of primordial curvature perturbations out of the anisotropy data of cosmic microwave background radiation. We applied it to the first-year data of WMAP and found that the primordial spectrum may have an oscillatory behavior.
4 We constructed models of inflation that account for the observed feature of density fluctuations by WMAP in which early star formation is also possible.
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