Updated on 2026/03/30

写真a

 
ISHIBASHI Akihiro
 
Organization
Graduate School of Science Professor
Graduate School
Graduate School of Science
Undergraduate School
School of Science Department of Physics
Title
Professor
External link
 

Papers 5

  1. Energy conditions and quantum information Invited Reviewed Open Access

    Norihiro Iizuka, Akihiro Ishibashi, Kengo Maeda, Haruki Nakayama, and Tatsuma Nishioka

    Canadian Journal of Physics   Vol. 104   page： 1 - 33   2026.3

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    Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

    DOI： https://doi.org/10.1139/cjp-2025-0271

    Open Access

  2. Ringdown in Vaidya spacetimes: Time-dependent frequencies, Penrose limit, and time-domain analyses Reviewed International coauthorship

    Chul-Moon Yoo, Masashi Kimura,Akihiro Ishibashi, and Rikuto Ohashi

    Physical Review D   Vol. 113   page： 044058   2026.2

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： https://doi.org/10.1103/r2vm-zgqn

  3. Self-gravitating strings and quantum effects in two-dimensional gravity Reviewed

    Akihiro Ishibashi, Yoshinori Matsuo & Akane Tanaka

    Journal of High Energy Physics   Vol. 2026 ( 2026 ) page： 165   2026.2

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    Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

    DOI： https://doi.org/10.48550/arXiv.2506.09586

  4. Bianchi-I cosmology with scale dependent G and Λ in asymptotically safe gravity Reviewed International coauthorship Open Access

    Chiang-Mei Chen, Akihiro Ishibashi, Rituparna Mandal and Nobuyoshi Ohta

    Classical and Quantum Gravity   Vol. 42 ( 23 ) page： 235008   2025.11

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1088/1361-6382/ae205a

    DOI： https://doi.org/10.48550/arXiv.2509.09759

    Open Access

  5. The higher dimensional instabilities of AdS in holographic semiclassical gravity Reviewed

    Akihiro Ishibashi, Kengo Maeda, Takashi Okamura

    Journal of High Energy Physics   Vol. 2025 ( 4 )   2025.4

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    Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

    Abstract

    In the framework of AdS/CFT duality, we consider the semiclassical problem in general quadratic theory of gravity. We construct asymptotically global AdS and hyperbolic (topological) AdS black hole solutions with non-trivial quantum hair in 4 and 5-dimensions by perturbing the maximally symmetric AdS solutions to the holographic semiclassical equations. We find that under certain conditions, our semiclassical solution of hyperbolic AdS black holes can be dynamically unstable against linear perturbations. In this holographic semiclassical context, we also study the thermodynamic instability of the hairy solutions in the 5-dimensional Gauss-Bonnet theory by computing the free energy and show that depending on the parameter of the Gauss-Bonnet theory, the free energy can be smaller than that of the background maximally symmetric AdS solution in both the global AdS and hyperbolic AdS black hole cases.

    DOI： 10.1007/jhep04(2025)167

    Other Link： https://link.springer.com/article/10.1007/JHEP04(2025)167/fulltext.html

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Books 1

  1. ブラックホールの数理【電子版】その大域構造と微分幾何

    石橋明浩（ Role： Sole author）

    2025.3  （ ISBN:9784781990347 ）

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Presentations 4

  1. Semiclassical Einstein equations and instability from holography Invited International conference

    Akihiro Ishibashi

    String Theory, Gravity, and Cosmology 2025  2025.12.4 

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    Event date： 2025.12

    Language：English   Presentation type：Oral presentation (invited, special)  

    Venue：Pohang · Korea  

  2. Semiclassical Einstein equations and instability from holography Invited

    Akihiro Ishibashi

    Extreme Universe International Conference  2025.10.27  Yukawa Institute for Theoretical Physics

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    Event date： 2025.10 - 2025.11

    Language：English   Presentation type：Oral presentation (invited, special)  

    Country：Japan  

  3. BMS Supertranslations and Gravitational Memory”（ Invited

    Akihiro Ishibashi

    Holography, Quantum Entanglement and Higher Spin Gravity 

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    Language：English  

  4. 物質分布のあるブラックホールからのリングダウン波

    石橋明浩

    日本物理学会  2025.9.16  日本物理学会

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    Presentation type：Oral presentation (general)  

    Venue：広島大学   Country：Japan  

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KAKENHI (Grants-in-Aid for Scientific Research) 3

  1. ホログラフィック理論による時空の量子相転移の解明

    Grant number：25K07306  2025.4 - 2029.3

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    前田 健吾, 石橋 明浩, 岡村 隆, 石橋 明浩, 岡村 隆

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    Authorship：Coinvestigator(s) 

    ブラックホールなどの強い重力場中では必ず時空特異点が発生することを主張する特異点定理やワームホールなどの非自明なトポロジーを持つ時空は存在しないと主張するトポロジー定理は、一般相対性理論における金字塔である。しかしながら、物質場の量子効果を考慮すると、定理に課されているエネルギー条件などは必ずしも成立しないことが知られている。量子重力理論が未完成な現時点において、本研究ではAdS/CFT対応を利用して、曲がった時空での物質場の量子効果を時空に取り入れ、その半古典方程式を解くことで、これまで知られていなかった時空の量子相転移や、エネルギー条件の解明、ブラックホール時空の安定性を解明する。

  2. The Natural Laws of Extreme Universe--A New Paradigm for Spacetime and Matter from Q uantum Information

    Grant number：21H05182  2021.9 - 2026.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Transformative Research Areas (A)

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    Authorship：Coinvestigator(s) 

  3. Black Holes and Singularities from Quantum Information

    Grant number：21H05186  2021.9 - 2026.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Transformative Research Areas (A)

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    Authorship：Principal investigator 

    Grant amount：\75140000 （ Direct Cost: \57800000 、 Indirect Cost：\17340000 ）

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Teaching Experience (On-campus) 1

  1. 力学特論演習・量子力学I演習

    2025

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