2022 Fiscal Year Research-status Report
The Hubble parameter experimental puzzle in the context of Modfied Gravity models
| Project/Area Number |
20K03969
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2025-03-31
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| Keywords | Cosmology / Modified gravity models |
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| Outline of Annual Research Achievements |
During the last year, we have been investigating how modified gravity models could face the tensions present in cosmology.
In particular, cosmology is facing two tensions: 1) the determination of H0, the
today's rate of expansion of the universe; 2) the rate of formation of structures in our universe. The predictions of general relativity in the presence of a cold dark matter fluid and of a cosmological constant seem to be not consistent with the most recent observations of these two observables. In particular, the first tension is about 5 sigmas, and at the moment, people seem to have checked all the possible systematics which can occur in the experimental determination of H0.
In the models, I have proposed with my collaborators, mostly Prof. Mukohyama (YITP) and Prof. Tsujikawa (Waseda U.), we have been pushing forward the idea that modified gravity models could account for both these tensions. We have used both powerful calculations and theoretical methods in order to explore the strengths and weaknesses of some of the models we have recently introduced in the literature.
I do hope that in the near future experimental data will be further tested to show the real presence of these tensions. If so, general relativity will require some modifications. Evidently, I want to further explore methods and ways to falsify (or prove) the theories I have been working on. The future might look very bright, hopefully. Since April 2022, I have published 9 papers in famous peer-review journals (JCAP, PRD, and PRL).
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The project is being completed more and more. The knowledge of new tools is still a work in progress, which will never end, since the field, the tools, and the data are keeping being updated.
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| Strategy for Future Research Activity |
In the next year, I want to pursue the investigation of modified gravity models and the way to use newer data to constrain them.
In particular, I want to use KiDS-1000 data to constrain the mass of the graviton.
Furthermore, I want to learn how to use N-body simulations (Fastpm or Ramses) to understand how the modified gravity models we have introduced can affect non-linear scales.
All these research fields will become more and more important in the near future, that is why I want to push forward learning the methods to understand gravity theories in principle at any scale (from astrophysical, galactic, and mostly cosmological ones).
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