| Project/Area Number |
18K13537
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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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 | Waseda University (2021-2022)
The University of Tokyo (2020)
Kyoto University (2018-2019) |
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Principal Investigator |
Fujita Tomohiro 早稲田大学, 高等研究所, 講師(任期付) (20815857)
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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 |
¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000)
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 | 宇宙論 / 重力波 / インフレーション / 宇宙の熱史 |
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| Outline of Final Research Achievements |
The main research theme was to investigate in detail the generation mechanism of primordial gravitational waves coming from the very early universe and their properties. It is highly likely that unknown matter existed in the early universe. We investigated when they emit gravitational waves and what kind of signatures they left behind in the emitted gravitational waves. First, gravitational waves emitted by known particles, U(1) and SU(2) gauge fields, were investigated. Then, we studied the model of 2-form fields predicted by string theory and general non-Abelian gauge fields that commonly produce gravitational waves. We also extensively studied alternative emission mechanisms such as the conversion of photons into gravitational waves under strong magnetic fields.
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| Academic Significance and Societal Importance of the Research Achievements |
近い将来に日本の打ち上げるLiteBIRD衛星などによって、極初期の宇宙から飛んでくる重力波が観測されると期待されている。そのような観測で判明する重力波の性質から、未知の初期宇宙の姿を描き出したい。そのためには、どのような物質が初期宇宙に存在したら、どのような重力波が作り出されるのか、その対応関係を知っておく必要がある。私のこの科研費研究では、様々な物質が様々な性質を持った重力波を放出する可能性を虱潰しに調べ上げることで、その対応関係のパターンを見つけていくことを狙いとした。期待通り、数多くの理論モデルを研究し、それを縦断する重力波放出の法則をある程度見出すことができた。
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