Theoretical research on methods to measure quantum natures of evaporating primordial black holes by using future observations

2022 Fiscal Year Annual Research Report

• Project Area: The Natural Laws of Extreme Universe--A New Paradigm for Spacetime and Matter from Quantum Information
• Project/Area Number: 22H05270
• Research Institution: High Energy Accelerator Research Organization
• Principal Investigator: 郡 和範 大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 准教授 (50565819)
• Project Period (FY): 2022-06-16 – 2024-03-31
• Keywords: 原始ブラックホール / 量子重力 / 修正重力理論 / バリオン数生成 / ダークマター / インフレーション / ビッグバン元素合成

Outline of Annual Research Achievements

2022年度は、査読付き論文を７本発表し、外部での講演を14回行った。その中でも、論文 4) K.　Kohri and K. i. Maeda, A possible solution to the helium anomaly of EMPRESS VIII by cuscuton gravity theory, PTEP, 2022, 9, 910、において、次のことを発表した。量子重力理論の候補である修正重力理論であるcuscuton gravityにおいて予言される重力定数は、標準的なニュートンの重力定数より小さい可能性がある。最近のすばるのEMPRESS VIIIチームによるヘリウム4のprimordial valueの観測が、標準ビッグバン元素合成による生成量より有意に小さい値を報告したが、これが正にcuscuton gravityで説明できることを指摘した。また、論文 5) M. He, K. Kohri, K. Mukaida and M. Yamada, Formation of hot spots around small primordial black holes, JCAP, 2023, 1, 27、において、次の内容を報告した。Big Bang Nucleosynthesisの時期の前に蒸発する原始ブラックホールの周りに、熱い火の玉が一瞬つくられる現象を詳しく調べた。この火の玉の中では、バリオン数やdark matterがつくられる可能性があり、全く新しい宇宙像を示している。これらの結論は、量子重力理論の量子性をテストする上で極めて重要で、オリジナルな成果である。

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

量子効果による蒸発する原始ブラックホールを観測することにより、重力の量子性のヒントを得るための理論的な準備はほぼ整った。具体的に、論文5) M. He, K. Kohri, K. Mukaida and M. Yamada, Formation of hot spots around small primordial black holes, JCAP, 2023, 1, 27、において、蒸発する原始ブラックホールの周りで、標準理論を越える量子現象が起き得ることを詳細な計算と共に示し、その結論を査読付き英文専門誌に論文として発表したことは、大きなマイルストーンであった。

Strategy for Future Research Activity

2023年度は、量子現象により蒸発ブラックホールの最期の様子を理論的に明らかにする研究を進める。特に、理論的には爆発的に蒸発することという特異な現象が起こる可能性が指摘されている。それを観測的に検証する方法について、理論的に解析を進めてゆく予定である。今年度の終了時に、その成果を論文にまとめ、査読付き英文専門誌に投稿する予定である。また、その成果を韓国とフランスで行われる専門的な国際会議で発表する予定である。

Remarks

他、新聞報道 4件 (合計新聞報道 9件)。

Research Products

• [Int'l Joint Research] Yonsei U(韓国)
  • Country Name: KOREA (REP. OF KOREA)
  • Counterpart Institution: Yonsei U
• [Int'l Joint Research] MPA(ドイツ)
  • Country Name: GERMANY
  • Counterpart Institution: MPA
• [Int'l Joint Research] CAS, Beijing(中国)
  • Country Name: CHINA
  • Counterpart Institution: CAS, Beijing
• [Journal Article] Formation of hot spots around small primordial black holes (2023)
  • Author(s): He Minxi、Kohri Kazunori、Mukaida Kyohei、Yamada Masaki
  • Journal Title: Journal of Cosmology and Astroparticle Physics Volume: 2023 Pages: 027～027
  • DOI: 10.1088/1475-7516/2023/01/027
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Threshold of primordial black hole formation againstvelocity dispersion in matter-dominated era (2023)
  • Author(s): Harada Tomohiro、Kohri Kazunori、Sasaki Misao、Terada Takahiro、Yoo Chul-Moon
  • Journal Title: Journal of Cosmology and Astroparticle Physics Volume: 2023 Pages: 038～038
  • DOI: 10.1088/1475-7516/2023/02/038
  • Peer Reviewed / Open Access
• [Journal Article] Search for Gamma-Ray Spectral Lines from Dark Matter Annihilation up to 100 TeV toward the Galactic Center with MAGIC (2023)
  • Author(s): Abe H.、and The MAGIC Collaboration, and Hiroshima N.、Kohri K.
  • Journal Title: Physical Review Letters Volume: 130 Pages: 61002
  • DOI: 10.1103/PhysRevLett.130.061002
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Probing primordial black holes with anisotropies in stochastic gravitational-wave background (2022)
  • Author(s): Wang Sai、Vardanyan Valeri、Kohri Kazunori
  • Journal Title: Physical Review D Volume: 106 Pages: 123511
  • DOI: 10.1103/PhysRevD.106.123511
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Cosmological 21-cm line observations to test scenarios of super-Eddington accretion on to black holes being seeds of high-redshifted supermassive black holes (2022)
  • Author(s): Kohri Kazunori、Sekiguchi Toyokazu、Wang Sai
  • Journal Title: Physical Review D Volume: 106 Pages: 43539
  • DOI: 10.1103/PhysRevD.106.043539
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] The inflaton that could: primordial black holes and second order gravitational waves from tachyonic instability induced in Higgs-R^2 inflation (2022)
  • Author(s): Cheong Dhong Yeon、Kohri Kazunori、Park Seong Chan
  • Journal Title: Journal of Cosmology and Astroparticle Physics Volume: 2022 Pages: 015～015
  • DOI: 10.1088/1475-7516/2022/10/015
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] A possible solution to the helium anomaly of EMPRESS VIII by cuscuton gravity theory (2022)
  • Author(s): Kohri Kazunori、Maeda Kei-ichi
  • Journal Title: Progress of Theoretical and Experimental Physics Volume: 2022 Pages: 910
  • DOI: 10.1093/ptep/ptac114
  • Peer Reviewed / Open Access
• [Presentation] Gamma-ray Emission from Primordial Black Holes (2023)
  • Author(s): Kazunori Kohri
  • Organizer: The extreme Universe viewed in very-high-energy gamma rays 2022
  • Int'l Joint Research
• [Presentation] Cosmological 21cm line observations to test scenarios of super-Eddington accretion on to seed BHs of high-z SMBHs (2022)
  • Author(s): Kazunori Kohri
  • Organizer: The hybrid-style symposium on Gravitational wave physics and astronomy: Genesis
  • Int'l Joint Research / Invited
• [Presentation] Primordial black holes and secondary gravitational waves in the inflationary Universe (2022)
  • Author(s): Kazunori Kohri
  • Organizer: Extreme Universe Online, Kick-Off Meeting of Publicly Offered Research Groups
  • Int'l Joint Research
• [Presentation] The sterile-active neutrino oscillation and lepto- and/or baryogenesis in the early Universe (2022)
  • Author(s): Kazunori Kohri
  • Organizer: Exploration of Particle Physics and Cosmology with Neutrino
  • Int'l Joint Research / Invited
• [Presentation] Cosmological 21cm line observations to test scenarios of super-Eddington accretion on to seed BHs of high-z SMBHs (2022)
  • Author(s): Kazunori Kohri
  • Organizer: 初代星・初代銀河研究会 2022
  • Int'l Joint Research / Invited
• [Presentation] Theoretical research on methods to measure quantum natures of evaporating primordial black holes by using future observations (2022)
  • Author(s): Kazunori Kohri
  • Organizer: The 2nd Annual Meeting on Extreme Universe
  • Int'l Joint Research
• [Presentation] Primordial black holes and induced gravitational waves in inflationery models (2022)
  • Author(s): Kazunori Kohri
  • Organizer: 東京女子大学 素粒子論セミナー
  • Invited
• [Presentation] MeV γ-ray/CMB: New eyes with which to see quantum nature of Primordial Black Holes (2022)
  • Author(s): Kazunori Kohri
  • Organizer: QUP Project Q workshop
  • Int'l Joint Research
• [Presentation] Cosmological 21cm line observations to test scenarios of super-Eddington accretion on to seed BHs of high-z SMBH (2022)
  • Author(s): Kazunori Kohri
  • Organizer: 筑波大学 天体形成研究会 2022_
  • Int'l Joint Research / Invited
• [Presentation] Testing the early matter-dominated epoch in the early Universe in terms of BBN, CMB, PBH, DM and GWs (2022)
  • Author(s): Kazunori Kohri
  • Organizer: The Future is Illuminating
  • Int'l Joint Research / Invited
• [Presentation] 1) Anisotropies of GWs from merging PBHs, and 2)PBHs and GWs from tachyonic instability induced in Higgs-R^2 inflation (2022)
  • Author(s): Kazunori Kohri
  • Organizer: Non-linear Gravitational wave
  • Int'l Joint Research / Invited
• [Presentation] Testing primordial black-hole dark matter by gamma-ray, gravitational wave, and strong lensing of fast radio bursts (2022)
  • Author(s): Kazunori Kohri
  • Organizer: CosPA 2022
  • Int'l Joint Research / Invited
• [Presentation] Recent topics of PBHs (2022)
  • Author(s): Kazunori Kohri
  • Organizer: Dynamics of primordial black hole formation
  • Int'l Joint Research / Invited
• [Book] 大人的宇宙學教室：透過微中子與重力波解密宇宙起源 (2022)
  • Author(s): Kazunori Kohri
  • Total Pages: 269
  • Publisher: 台灣東販
  • ISBN: 9786263292758
• [Remarks] 巨大望遠鏡で狙う暗黒物質からの”光”天の川銀河中心観測で解き明かす宇宙暗黒物質の起源と正体
  • URL: https://www.icrr.u-tokyo.ac.jp/news/13105/
• [Remarks] 科学にフォーカス、宇宙の膨張が加速、暗黒エネルギーの謎 [信濃毎日新聞]
  • URL: http://www2.yukawa.kyoto-u.ac.jp/~kazunori.kohri/KyouDouFiles20221104/Shinano-Mainichi-Shinbun-1002.pdf
• [Remarks] 科学がわかった！宇宙が加速膨張、謎の暗黒エネルギーが要因か？ [山陽新聞]
  • URL: http://www2.yukawa.kyoto-u.ac.jp/~kazunori.kohri/KyouDouFiles20221104/San-You-Shinbun-20220925.pdf
• [Remarks] 科学がわかった Science Q＆A、暗黒エネルギー、宇宙膨張、加速する力 [愛媛新聞]
  • URL: http://www2.yukawa.kyoto-u.ac.jp/~kazunori.kohri/KyouDouFiles20221104/Ehime-Shinbun-20220818.pdf
• [Remarks] 科学がわかった！宇宙を膨張させる力、暗黒エネルギーが加速要因 [高知新聞]
  • URL: http://www2.yukawa.kyoto-u.ac.jp/~kazunori.kohri/KyouDouFiles20221104/Kouchi-Shinbun-20220814.pdf
• [Funded Workshop] The KEK-PH + KEK-Cosmo + QUP joint lectures and workshops 2023 on "Hubble Tension 2023" (2023)