Researchers

ISHIBASHI Akihiro

ISHIBASHI Akihiro
Professor/Senior Staff
Faculty Department of Science / Graduate School of Science and Engineering
Researchmap https://researchmap.jp/akihiroishibashi

Education and Career

Education

  • 1993 - 1995 , Tokyo Institute of Technology, Graduate School of Science and Engineering,
  • 1995 - 1998 , Tokyo Institute of Technology, Graduate School of Science and Engineering,

Academic & Professional Experience

  • 2011 - 2013 , Kindai University Faculty of Science and Engineering 准教授
  • 2007 - 2011 , High Energy Accelerator Research Organization
  • 2005 - 2007 , Enrico Fermi Institute, The University of Chicago
  • 2003 - 2005 , DAMTP, University of Cambridge
  • 2000 - 2003 , 日本学術振興会特別研究員ＰＤ（京都大学基礎物理学研究所）

Research Activities

Research Areas

  • Natural sciences, Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics

Research Interests

宇宙物理, 数理物理, 重力理論, 素粒子, 相対論, 超弦理論

Published Papers

  1. Symmetry breaking of 3-dimensional AdS in holographic semiclassical gravity
    Akihiro Ishibashi; Kengo Maeda; Takashi Okamura
    Journal of High Energy Physics  2024  (2)  21, Feb. 2024 
  2. Flows of rotating extremal attractor black holes
    Norihiro Iizuka; Akihiro Ishibashi; Kengo Maeda
    Journal of high energy physics  2023  (08)  , 177-1-177-18, Aug. 2023  , Refereed
  3. Semiclassical Einstein equations from holography and boundary dynamics
    Akihiro Ishibashi; Kengo Maeda; Takashi Okamura
    Journal of High Energy Physics  2023  (5)  26, May. 2023 

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Conference Activities & Talks

  1. ブラックホールの数理：その大域構造と安定性 , 石橋明浩 , 日本物理学会74 回年次大会・シンポジウム招待講演・九州大学 , Mar. 2019
  2. Asymptotic symmetry and Memory effects , Akihiro Ishibashi , Infrared physics of gauge theories and quantum dy- namics of in ation , 20, Jan. 2018
  3. 高次元重力 , 石橋明浩 , 第２８回理論懇談会シンポジウム , 22, Dec. 2016

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MISC

  1. Chronology Protection and Non-Naked Singularity , Kengo Maeda; Akihiro Ishibashi; Makoto Narita , Class.Quant.Grav.15:1637-1651,1998 , 5, Mar. 1998
    Summary:We test the chronology protection conjecture in classical general relativity<br /> by investigating finitely vicious space-times. First we present singularity<br /> theorems in finitely vicious space-times by imposing some restrictions on the<br /> chronology violating sets. In the theorems we can refer to the location of an<br /> occurring singularity and do not assume any asymptotic conditions such as the<br /> existence of null infinities. Further introducing the concept of a non-naked<br /> singularity, we show that a restricted class of chronology violations cannot<br /> arise if all occurring singularities are the non-naked singularities. Our<br /> results suggest that the causal feature of the occurring singularities is the<br /> key to prevent the appearance of causality violation.
  2. Upper bound for entropy in asymptotically de Sitter space-time , Kengo Maeda; Tatsuhiko Koike; Makoto Narita; Akihiro Ishibashi , Phys.Rev. D57 (1998) 3503-3508 , 5, Dec. 1997
    Summary:We investigate nature of asymptotically de Sitter space-times containing a<br /> black hole. We show that if the matter fields satisfy the dominant energy<br /> condition and the cosmic censorship holds in the considering space-time, the<br /> area of the cosmological event horizon for an observer approaching a future<br /> timelike infinity does not decrease, i.e. the second law is satisfied. We also<br /> show under the same conditions that the total area of the black hole and the<br /> cosmological event horizon, a quarter of which is the total Bekenstein-Hawking<br /> entropy, is less than $12\pi/\Lambda$, where $\Lambda$ is a cosmological<br /> constant. Physical implications are also discussed.
  3. Strong Cosmic Censorship and Causality Violation , Kengo Maeda; Akihiro Ishibashi , Phys.Rev. D56 (1997) 2094-2099 , 24, Jul. 1996
    Summary:We investigate the instability of the Cauchy horizon caused by causality<br /> violation in the compact vacuum universe with the topology $B\times {\bf<br /> S}^{1}\times {\bf R}$, which Moncrief and Isenberg considered. We show that if<br /> the occurrence of curvature singularities are restricted to the boundary of<br /> causality violating region, the whole segments of the boundary become curvature<br /> singularities. This implies that the strong cosmic censorship holds in the<br /> spatially compact vacuum space-time in the case of the causality violation.<br /> This also suggests that causality violation cannot occur for a compact<br /> universe.

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Awards & Honors

  1. 2014, 湯川記念財団・木村利栄理論物理学賞
  2. 2007, 中村誠太郎賞
  3. 2007, 日本物理学会論文賞

Research Grants & Projects

  1. 日本学術振興会, 科学研究費助成事業, 量子情報を用いた量子ブラックホールの数理の解明 , 近畿大学
  2. Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The Natural Laws of Extreme Universe--A New Paradigm for Spacetime and Matter from Q uantum Information , Kyoto University
  3. Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Massive field perturbations on black hole spacetime , Kindai University

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