| Project/Area Number |
18K03616
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 15010:Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics
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| Research Institution | Nagoya University |
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Principal Investigator |
Ichiki Kiyotomo 名古屋大学, 素粒子宇宙起源研究所, 准教授 (10534480)
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| Project Period (FY) |
2018-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2022: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2021: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2020: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
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| Keywords | 宇宙大規模構造 / 宇宙マイクロ波背景輻射 / 初期密度揺らぎ / 暗黒エネルギー / 初期宇宙密度揺らぎ |
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| Outline of Final Research Achievements |
In modern cosmology, the statistical magnitude of the density fluctuations generated in the early universe is measured at different epochs of the universe to determine the cosmological model. In recent years, detector noise has become less of an issue in these measurements, and instead, the sample variance, where there is only one universe to observe, determines the limit of the power of the test. We explored the possibility of choosing the cosmological model by directly following the growth of the fluctuations rather than the statistics of the fluctuations. We found that the growth of the fluctuations can be separated from the size of the initial fluctuations by assuming that the distribution of the initial fluctuations is Gaussian and that the growth of the fluctuations can be estimated directly by observing the polarisation of the cosmic microwave background radiation produced in a galaxy cluster at each time.
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| Academic Significance and Societal Importance of the Research Achievements |
宇宙論研究においては、揺らぎの平均や分散といった統計量を観測量として用いて宇宙モデルの決定を行っていますが、これは宇宙が統計的に一様で等方的であるということが暗に仮定されています。これは近代宇宙論では宇宙原理と呼ばれる標準的な仮定ではありますが、本研究は、その仮定を排除して直接的に宇宙の構造の進化を追うにはどうしたらよいか、という課題に取り組んでおり、いくつかの方法を提示したものになっています。
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