Why does the Universe accelerate? -Exhaustive study and challenge for the future-

• Project Area: Why does the Universe accelerate? - Exhaustive study and challenge for the future -
• Project/Area Number: 15H05887
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Science and Engineering
• Research Institution: The University of Tokyo
• Principal Investigator: MURAYAMA HITOSHI 東京大学, カブリ数物連携宇宙研究機構, 教授 (20222341)
• Co-Investigator(Kenkyū-buntansha): 片山 伸彦 東京大学, カブリ数物連携宇宙研究機構, 教授 (50290854) ; 樽家 篤史 京都大学, 基礎物理学研究所, 准教授 (40334239)
• Project Period (FY): 2015-06-29 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥28,210,000 (Direct Cost: ¥21,700,000、Indirect Cost: ¥6,510,000); Fiscal Year 2019: ¥9,490,000 (Direct Cost: ¥7,300,000、Indirect Cost: ¥2,190,000); Fiscal Year 2018: ¥7,540,000 (Direct Cost: ¥5,800,000、Indirect Cost: ¥1,740,000); Fiscal Year 2017: ¥7,540,000 (Direct Cost: ¥5,800,000、Indirect Cost: ¥1,740,000); Fiscal Year 2016: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000); Fiscal Year 2015: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
• Keywords: インフレーション / ダークエネルギー / ダークマター / ニュートリノ / 宇宙物理 / 素粒子 / 宇宙線

Outline of Final Research Achievements

The purpose of this innovative research area is to reveal the physics driving accelerating expansion of the universe that should have occurred at the beginning and is now happening today. Main achievements of our program are as follows. (1) Researchers in this program proposed the so-called "swampland" conjecture claiming that low-energy effective field theories involving gravity and quantum field theory are not compatible with string theory. (2) Using high-precision measurements of gravitational lensing effects from the Subaru imaging data, we obtained cosmological parameters. (3) We carried out theoretical and observational researches on primordial black holes that are candidates of dark matter and LIGO gravitational wave counterparts. (4) We carried out developments of instrumentation on the cosmic microwave background experiments and the Subaru multi-object spectrograph.

Academic Significance and Societal Importance of the Research Achievements

加速宇宙の物理機構の解明に向け、すばる望遠鏡搭載の超広視野主焦点カメラHSCを用いたダークマターの3次元地図の作成、および宇宙論パラメータの測定、すばる超広視野多天体分光器PFSプロジェクトの準備研究、次世代宇宙マイクロ派背景放射CMB探査計画の推進を行った。加えて、異なる宇宙論データの横断的、統合的解析の新たな手法の開発、原始ブラックホールの理論的、観測的研究の新展開、なども得られた。また、超弦理論のみならず素粒子現象論やモデル・ビルディング、宇宙論に大きな影響を与えた量子重力のスワンプランド条件等の究極理論の知見を得て、領域研究への展開を得た。

Research Products

• [Journal Article] Finite-Size Dark Matter and its Effect on Small-Scale Structure (2020)
  • Author(s): Chu Xiaoyong、Garcia-Cely Camilo、Murayama Hitoshi
  • Journal Title: Physical Review Letters Volume: 124 Issue: 4 Pages: 1-7
  • DOI: 10.1103/physrevlett.124.041101
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Testing the Seesaw Mechanism and Leptogenesis with Gravitational Waves (2020)
  • Author(s): Dror Jeff A.、Hiramatsu Takashi、Kohri Kazunori、Murayama Hitoshi、White Graham
  • Journal Title: Physical Review Letters Volume: 124 Issue: 4 Pages: 1-6
  • DOI: 10.1103/physrevlett.124.041804
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Baryogenesis from a dark first-order phase transition (2020)
  • Author(s): Hall Eleanor、Konstandin Thomas、McGehee Robert、Murayama Hitoshi、Servant Geraldine
  • Journal Title: Journal of High Energy Physics Volume: 2020 Issue: 4 Pages: 1-14
  • DOI: 10.1007/jhep04(2020)042
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Erratum to: 2, 84, 30, 993, 560, 15456, 11962, 261485, …: higher dimension operators in the SM EFT (2019)
  • Author(s): Henning Brian、Lu Xiaochuan、Melia Tom、Murayama Hitoshi
  • Journal Title: Journal of High Energy Physics Volume: 2019 Issue: 9 Pages: 1-2
  • DOI: 10.1007/jhep09(2019)019
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] What does inflation say about dark energy given the swampland conjectures? (2019)
  • Author(s): Chiang Chien-I、Leedom Jacob M.、Murayama Hitoshi
  • Journal Title: Physical Review D Volume: 100 Issue: 4 Pages: 1-8
  • DOI: 10.1103/physrevd.100.043505
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Twin Higgs model with strongly interacting massive particle dark matter (2019)
  • Author(s): Hochberg Yonit、Kuflik Eric、Murayama Hitoshi
  • Journal Title: Physical Review D Volume: 99 Issue: 1 Pages: 1-7
  • DOI: 10.1103/physrevd.99.015005
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Velocity Dependence from Resonant Self-Interacting Dark Matter (2019)
  • Author(s): Chu Xiaoyong、Garcia-Cely Camilo、Murayama Hitoshi
  • Journal Title: Physical Review Letters Volume: 122 Issue: 7 Pages: 1-8
  • DOI: 10.1103/physrevlett.122.071103
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Strongly interacting massive particles through the axion portal (2018)
  • Author(s): Hochberg Yonit、Kuflik Eric、McGehee Robert、Murayama Hitoshi、Schutz Katelin
  • Journal Title: Physical Review D Volume: 98 Issue: 11 Pages: 1-13
  • DOI: 10.1103/physrevd.98.115031
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Cosmologically viable low-energy supersymmetry breaking (2018)
  • Author(s): Hook Anson、McGehee Robert、Murayama Hitoshi
  • Journal Title: Physical Review D Volume: 98 Issue: 11 Pages: 1-1
  • DOI: 10.1103/physrevd.98.115036
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Do We Live in the Swampland? (2018)
  • Author(s): Hitoshi Murayama, Masahito Yamazaki, Tsutomu T. Yanagida
  • Journal Title: JHEP Volume: 1812 Issue: 12 Pages: 032-032
  • DOI: 10.1007/jhep12(2018)032
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Remarks] 新学術領域「なぜ宇宙は加速するのか？-徹底的究明と将来への挑戦-
  • URL: http://acceleration.ipmu.jp/
• [Remarks] 東京大学国際高等研究所カブリ数物連携宇宙研究機構
  • URL: https://www.ipmu.jp/ja
• [Remarks] 新学術領域「なぜ宇宙は加速するのか？-徹底的究明と将来への挑戦-」
  • URL: http://acceleration.ipmu.jp
• [Remarks] カブリ数物連携宇宙研究機構
  • URL: http://www.ipmu.jp
• [Remarks] 新学術領域研究「なぜ宇宙は加速するのか? -徹底的究明と将来への挑戦 -
  • URL: http://acceleration.ipmu.jp
• [Remarks] カブリ数物連携宇宙研究機
  • URL: http://www.ipmu.jp/j
• [Remarks] 新学術領域研究「なぜ宇宙は加速するのか? -徹底的究明と将来への挑戦 -」
  • URL: http://acceleration.ipmu.jp/
• [Remarks] カブリ数物連携宇宙研究機構
  • URL: http://www.ipmu.jp/ja
• [Funded Workshop] Cosmic Acceleration (2020)
• [Funded Workshop] 新学術領域「なぜ宇宙は加速するのか？-徹底的究明と将来への挑戦-」MAR2019 (2019)
• [Funded Workshop] 新学術「加速宇宙」"Accelerating Universe in the Dark" (2019)
• [Funded Workshop] 新学術領域「なぜ宇宙は加速するのか？-徹底的究明と将来への挑戦-」（Why does the Universe accelerate?-Exhaustive study and challenge for the future）-MAR2019 (2019)
• [Funded Workshop] 新学術領域「加速宇宙」"Accelerating Universe in the Dark" (2019)
• [Funded Workshop] 新学術領域「なぜ宇宙は加速するのか？-徹底的究明と将来への挑戦-」（Why does the Universe accelerate?-Exhaustive study and challenge for the future）-FEB2018 (2018)
• [Funded Workshop] Why does the Universe accelerate? -Exhaustive study and challenge for the future- (2017)
  • Place of Presentation: KEK、茨城県・つくば
  • Year and Date: 2017-03-08