| 研究実績の概要 |
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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