2022 Fiscal Year Final Research Report
Gravity and cosmology beyond general relativity
| Project/Area Number |
17H02890
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2017-04-01 – 2022-03-31
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| Keywords | 宇宙物理 / 天文学 |
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| Outline of Final Research Achievements |
Through challenging the mysteries of the universe, we approached the essence of gravity, set the construction of a gravitational theory beyond general relativity as a goal, and succeeded in constructing a general theoretical framework for that purpose. We have succeeded for the first time in extending the effective field theory of scalar-tensor gravity with timelike scalar profile to arbitrary backgrounds, not just flat space-time and homogeneous isotropic universe. Also, in the homogeneous and isotropic cosmological background, we succeeded in constructing an effective field theory that can universally describe all vector-tensor theories. In addition, we discovered the minimal theory of bigravity (MTBG), which eliminates all possible fatal instabilities.
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| Free Research Field |
重力理論と宇宙論
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| Academic Significance and Societal Importance of the Research Achievements |
本研究において世界で初めて構築した２つの有効場の理論は、重力波の観測と宇宙論スケールの観測と、重力理論をつなぐ架け橋の役割を果たすと期待される。特に、様々なダークエネルギー理論を観測から制限するのに有用と考えられる。また、MTBGは、初期宇宙を含めた様々な状況に適用可能で、重力子の質量項がダークエネルギーの代わりになって宇宙膨張を加速させることもできるので、重力波観測によってmassive gravityをテストする理論的土台を与えるだけでなく、ダークエネルギーの謎を解くためのヒントにもなる可能性がある。
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