| 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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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 2003: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2002: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
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| Keywords | dark matter / dark energy / axion / cosmic microwave background radiation / density fluctuations / inflation / primordial spectrum / cosmological constant / スペクトル / WMAP / 再イオン化 / 宇宙年齢 / 銀河の化学進化 / 宇宙背景放射 / 宇宙論 / 初期密度ゆらぎ / 真空のエネルギー / インスタントン / ブレインワールド / 超重力理論 |
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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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