| Project/Area Number |
18F18315
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| Research Category |
Grant-in-Aid for JSPS Fellows
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| Allocation Type | Single-year Grants |
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| Section | 外国 |
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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 | Kyoto University |
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Principal Investigator |
向山 信治 京都大学, 基礎物理学研究所, 教授 (40396809)
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| Co-Investigator(Kenkyū-buntansha) |
ZHANG YUN-LONG 京都大学, 基礎物理学研究所, 外国人特別研究員
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| Project Period (FY) |
2018-11-09 – 2021-03-31
|
| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2020: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2019: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2018: ¥600,000 (Direct Cost: ¥600,000)
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| Keywords | gravitation / cosmology / holographic principle / gravitatioal waves |
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| Outline of Annual Research Achievements |
Two journal papers have been published in FY2020:
1.1] In "Universal Upper Bound on the Inflationary Energy Scale from the Trans-Planckian Censorship Conjecture" [Phys. Rev. D 102, 021301 (2020)], we studied the constraint on the inflationary energy scale from the recently proposed Trans-Planckian Censorship Conjecture (TCC). We found a universal upper bound on the inflationary Hubble expansion rate H, which is solely determined by the reheating temperature: H < T0/Tr, where T0 is the photon temperature today. The upper limit can be saturated by a post-inflationary oscillatory stage with the critical equation-of-state parameter w=-1/3, or by an inflation model with multiple stages. In the lowest reheating temperature required for big bang nucleosynthesis, the upper bound on the tensor-to-scalar ratio r at the CMB scales is r < 10^{－8}, which can be realized in some string-inspired inflation models.
1.2] In "Notes on the Quantum Corrections of Swampland and Trans-Planckian Censorship Conjecture" [Phys.Lett. B 816 (2021) 136245], we discussed the de Sitter swampland and trans-Planckian censorship conjectures (TCC) from the entropy bound with quantum corrections, namely quantum version of the Bousso bound and energy conditions. We included the typical contributions from the entanglement entropy in quasi-de Sitter spacetime. The TCC is not much corrected, whereas the bounds on de Sitter swampland conjecture from energy conditions can be relaxed due to quantum corrections.
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| Research Progress Status |
令和2年度が最終年度であるため、記入しない。
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| Strategy for Future Research Activity |
令和2年度が最終年度であるため、記入しない。
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