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2020 Fiscal Year Annual Research Report

Black Holes and Cosmology in Holographic Duality and Gravitational Waves

Research Project

Project/Area Number 18F18315
Research InstitutionKyoto University

Principal Investigator

向山 信治  京都大学, 基礎物理学研究所, 教授 (40396809)

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
Project Period (FY) 2018-11-09 – 2021-03-31
Keywordsgravitation / cosmology / holographic principle / gravitatioal waves
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.

Research Progress Status

令和2年度が最終年度であるため、記入しない。

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。

  • Research Products

    (5 results)

All 2021 2020

All Journal Article (2 results) (of which Int'l Joint Research: 1 results,  Peer Reviewed: 2 results,  Open Access: 1 results) Presentation (3 results) (of which Int'l Joint Research: 3 results,  Invited: 1 results)

  • [Journal Article] Notes on quantum corrections of swampland and trans-Planckian censorship conjectures2021

    • Author(s)
      Sun Sichun、Zhang Yun-Long
    • Journal Title

      Physics Letters B

      Volume: 816 Pages: 136245~136245

    • DOI

      10.1016/j.physletb.2021.136245

    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Universal upper bound on the inflationary energy scale from the trans-Planckian censorship conjecture2020

    • Author(s)
      Mizuno Shuntaro、Mukohyama Shinji、Pi Shi、Zhang Yun-Long
    • Journal Title

      Physical Review D

      Volume: 102

    • DOI

      10.1103/PhysRevD.102.021301

    • Peer Reviewed / Open Access
  • [Presentation] From Rindler fluid to dark fluid on the holographic cutoff surface2020

    • Author(s)
      Yun-Long Zhang
    • Organizer
      4th International conference on holography, string theory and discrete approach in Hanoi, Vietnam
    • Int'l Joint Research / Invited
  • [Presentation] Gravitational Waves and Possible Fast Radio Bursts from Axion Clumps2020

    • Author(s)
      Yun-Long Zhang
    • Organizer
      14th International Conference on Gravitation, Astrophysics and Cosmology ICGAC14
    • Int'l Joint Research
  • [Presentation] Gravitational Waves and Possible Fast Radio Bursts from Axion Clumps2020

    • Author(s)
      Yun-Long Zhang
    • Organizer
      The 30th Workshop on General Relativity and Gravitation in Japan (JGRG30) (online)
    • Int'l Joint Research

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Published: 2021-12-27  

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