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Modified gravity and its cosmology

Research Project

Project/Area Number 15F15321
Research Category

Grant-in-Aid for JSPS Fellows

Allocation TypeSingle-year Grants
Section外国
Research Field Particle/Nuclear/Cosmic ray/Astro physics
Research InstitutionKyoto University

Principal Investigator

佐々木 節  京都大学, 基礎物理学研究所, 教授 (70162386)

Co-Investigator(Kenkyū-buntansha) LIN CHUNSHAN  京都大学, 基礎物理学研究所, 外国人特別研究員
Project Period (FY) 2015-11-09 – 2018-03-31
Project Status Completed (Fiscal Year 2017)
Budget Amount *help
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2017: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 2016: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2015: ¥700,000 (Direct Cost: ¥700,000)
Keywords修正重力理論 / 宇宙論的重力波 / 非ガウス原始揺らぎ / 有限質量重力理論 / 非ガウス揺らぎ / 原始宇宙磁場 / インフレーション宇宙
Outline of Annual Research Achievements

In addition to discussing general properties of modified gravity theories, our research in FY2017 focused particularly on clarifying possible observational signatures predicted by an inflationary massive gravity model we proposed in FY2016. The following are the main results:
1. We pointed out the possible scale dependence of CMB non-Gaussianity arising from a large tensor-scalar-scalar coupling during inflation, and that this non-Gaussian feature may be already seen in the observational data obtained by WMAP and Planck.
2.We found a class of minimally modified gravity theories, of which graviton has only two dynamical degrees of freedom, challenging the singular role of general relativity as the unique non-linear theory of massless spin-2 particles.
3. We studied the evolution of gravitational waves in the inflationary massive gravity model in which graviton undergoes a parametric resonance after inflation. We found a sharp peak in the energy density spectrum of stochastic gravitational wave background due to the parametric resonance. This peak may be detected in the near future either by ground-based or space-based gravitational wave detectors.

Research Progress Status

29年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

29年度が最終年度であるため、記入しない。

Report

(3 results)
  • 2017 Annual Research Report
  • 2016 Annual Research Report
  • 2015 Annual Research Report
  • Research Products

    (11 results)

All 2017 2016 2015 Other

All Int'l Joint Research (4 results) Journal Article (5 results) (of which Int'l Joint Research: 5 results,  Peer Reviewed: 5 results,  Open Access: 3 results,  Acknowledgement Compliant: 2 results) Presentation (2 results) (of which Int'l Joint Research: 2 results)

  • [Int'l Joint Research] 香港科学技術大学(中国)

    • Related Report
      2017 Annual Research Report
  • [Int'l Joint Research] マギル大学(カナダ)

    • Related Report
      2017 Annual Research Report
  • [Int'l Joint Research] 香港工科大学(香港)

    • Related Report
      2016 Annual Research Report
  • [Int'l Joint Research] 香港科技大学(香港)

    • Related Report
      2015 Annual Research Report
  • [Journal Article] A class of minimally modified gravity theories2017

    • Author(s)
      Lin Chunshan , Mukohyama Shinji
    • Journal Title

      Journal of Cosmology and Astroparticle Physics

      Volume: 2017 Issue: 10 Pages: 033-033

    • DOI

      10.1088/1475-7516/2017/10/033

    • Related Report
      2017 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] CMB scale dependent non-Gaussianity from massive gravity during inflation2017

    • Author(s)
      Dom?nech Guillem、Hiramatsu Takashi、Lin Chunshan、Sasaki Misao、Shiraishi Maresuke、Wang Yi
    • Journal Title

      Journal of Cosmology and Astroparticle Physics

      Volume: 2017 Issue: 05 Pages: 034-034

    • DOI

      10.1088/1475-7516/2017/05/034

    • Related Report
      2017 Annual Research Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Inflationary Magnetogenesis with Broken Local U(1) Symmetry2016

    • Author(s)
      Guillem Domenech, Chunshan Lin, Misao Sasaki
    • Journal Title

      Europhysics Letters

      Volume: 115 Issue: 1 Pages: 19001-19001

    • DOI

      10.1209/0295-5075/115/19001

    • Related Report
      2016 Annual Research Report
    • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Resonant primordial gravitational waves amplification2016

    • Author(s)
      Chunshan Lin, Misao Sasaki
    • Journal Title

      Physics Letters B

      Volume: 752 Pages: 84-88

    • DOI

      10.1016/j.physletb.2015.11.021

    • NAID

      120005753862

    • Related Report
      2015 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Effective Field Theory of Broken Spatial Diffeomorphisms2016

    • Author(s)
      Chunshan Lin, Lance Z. Labun
    • Journal Title

      JHEP (Journal of High Energy Physics)

      Volume: 1603 Issue: 3 Pages: 128-128

    • DOI

      10.1007/jhep03(2016)128

    • NAID

      120005980951

    • Related Report
      2015 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Presentation] A new theory of modified gravity?2017

    • Author(s)
      Chunshan Lin
    • Organizer
      The 21st annual International Conference on Particle Physics and Cosmology (COSMO-17)
    • Related Report
      2017 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Inflatioinary magnetogensis with broken U(1) symmetry2015

    • Author(s)
      Chunshan Lin
    • Organizer
      2nd Lecospa symposium "everything about gravity"
    • Place of Presentation
      National Taiwan University, Taipei, Taiwan
    • Year and Date
      2015-12-17
    • Related Report
      2015 Annual Research Report
    • Int'l Joint Research

URL: 

Published: 2015-11-26   Modified: 2024-03-26  

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