| Project/Area Number |
21K20366
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| Research Category |
Grant-in-Aid for Research Activity Start-up
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| Allocation Type | Multi-year Fund |
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| Review Section |
0203:Particle-, nuclear-, astro-physics, and related fields
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| Research Institution | The University of Tokyo |
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Principal Investigator |
Eby Joshua 東京大学, カブリ数物連携宇宙研究機構, 特任研究員 (50902095)
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| Project Period (FY) |
2021-08-30 – 2024-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2022: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2021: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
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| Keywords | Dark matter / Local density / Gravitational atoms / Dark matter capture / Ultralight fields / Axions / dark matter / axions / ultralight particles / astrophysics / axion stars / gravitational atoms / Dark Matter / Axion stars / Bound axion halos / Astrophysics / Axion Stars / Axion Halos |
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| Outline of Research at the Start |
This work is intended to elucidate the nature of dark matter by determining how it would appear at the position of the Earth, where experimentalists are working to measure its properties. If dark matter is made of particles called axions, then the usual assumption about the prevalence of dark matter particles may be significantly modified. We may find that most of dark matter is not freely-floating through the galaxy, but rather bound in some astrophysical objects, which will modify the best search strategies. We hope that by analyzing axion theories carefully, we will clarify these issues.
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| Outline of Final Research Achievements |
For the first time, we have shown that asteroid tracking data is precise enough, and systematic uncertainties are controlled well enough, to set a competitive constraint on the dark matter density in the solar system. Previous constraints from planets are unlikely to improve, but our method could allow for rapid improvement in the future.
The other key achievement was to show that ultralight dark matter can be efficiently captured around astrophysical bodies, including stars like the Sun. Contrary to the previous expectation in the research literature, we showed how the capture of these fields can be exponentially enhanced by bosonic statistics and gravitational focusing of the field, giving rise to extremely striking predictions for the local density of dark matter. Our method is extremely generic, and can be directly applied to other systems, including planets and black holes; indeed, since our work appeared a number of follow-up studies have begun to investigate these systems.
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| Academic Significance and Societal Importance of the Research Achievements |
Our work has shown that asteroids can be used to set novel constraints on the local dark matter density, that dark matter can be captured in the solar system leading to new predictions for experiment, and proposed a novel space-based quantum sensing experiment to discover dark matter.
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