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2006 Fiscal Year Final Research Report Summary

Research on the evolution of the Universe based on high precision data

Research Project

Project/Area Number 16340076
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Particle/Nuclear/Cosmic ray/Astro physics
Research InstitutionThe University of Tokyo (2005-2006)
Osaka University (2004)

Principal Investigator

JUN'ICHI Yokoyama  The University of Tokyo, The University of Tokyo, Graduate School of Science, Professor (50212303)

Co-Investigator(Kenkyū-buntansha) TORU Tsuribe  Osaka University, Graduate School of Science, Research Assistant (60335338)
MASAHIRO Yamaguchi  Tohoku University, Graduate School of Science, Professor (10222366)
Project Period (FY) 2004 – 2006
Keywordscosmic microwave background / density fluctuation / power spectrum / inflation / supergravity / primordial black holes / primordial magnetic field
Research Abstract

This research project was originally planned to make a consistent evolution history of the early Universe which can account for the two new features of the first-year WMAP results, namely, running of spectral index of the curvature perturbations and early star formation which realizes early reionization based on the model of inflation proposed by the head investigator and collaborators. The other purpose of the project was to pursue the cosmological consequences of heavy moduli fields and gravitinos on dark matter formation and the thermal history. While the project itself was put into practice as we originally designed, the three-year WMAP data, which was disclosed during the research period of this project, withdrew their previous claim of early reionization, so that we reorganized the project accordingly. The main research outcomes are listed as follows.
1 We discovered parametric amplification of density perturbations in our model of inflation which can result in intermediate mass primordial black hole formation.
2 We established a proper formulation of curvature perturbation in the situation where motion of multiple scalar fields determines the trajectory of the inflaton.
3 We calculated the constraint on the neutrino mass in the presence of running spectral index and obtained a more stringent bound than before.
4 We analyzed modulus decay to gravitinos and their subsequent decay to neutralino dark matter and showed there was a parameter region that realizes the proper dark matter abundance.
5 We formulated fate of the oscillating scalar fields using nonequilibrium quantum field theory.
6 We proposed a method to reconstruct primordial power spectrum of fluctuations out of the polarization data of the cosmic microwave background radiation.
7 We reconstructed primordial power spectrum using both cosmic inversion and maximum-likelihood matrix method.

  • Research Products

    (21 results)

All 2008 2007 2006

All Journal Article (17 results) Book (4 results)

  • [Journal Article] Generation of Large-Scale Magnetic Fields in Single-Field Inflation2008

    • Author(s)
      Jerome Martin, 横山順一
    • Journal Title

      JCAP 0801

      Pages: 025

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Generation of Large-Scale Magnetic Fields in Single-Field Inflation2008

    • Author(s)
      J.Martin, J.Yokoyama
    • Journal Title

      JCAP Vol.0801

      Pages: 025

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Time variations of proton-electron mass ratlo and fine structure constant with runaway dilaton2007

    • Author(s)
      千葉剛、小林達夫、山口昌英、横山順一
    • Journal Title

      Physical Review D75

      Pages: 043516

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Lepton asymmetry in the primordial gravitational wave spectrum2007

    • Author(s)
      市來淨與、山口昌英、横山順一
    • Journal Title

      Physical Review D75

      Pages: 084017

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Effective Search Templates for a Primordial Stochastic Gravitational Wave Background2007

    • Author(s)
      千葉剛、姫本宣朗、山口昌英、横山順一
    • Journal Title

      Physical Review D76

      Pages: 043516

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Time variation of proton - electron mass ratio and fine structure constant with runaway dilaton2007

    • Author(s)
      T.Chiba, T.Kobayashi, M.Yamaguchi, J.Yokoyama
    • Journal Title

      Phys.Rev.D Vol.75

      Pages: 043516

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Lepton asymmetry in the primordial gravitational wave spectrum2007

    • Author(s)
      K.Ichiki, M.Yamaguchi, J.Yokoyama
    • Journal Title

      Phys.Rev.D Vol.75

      Pages: 084017

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] power Spectrum of the Density Perturbations From Smooth Hybrid New Inflation Model2006

    • Author(s)
      川崎雅裕、高山努、山口昌英、横山順一
    • Journal Title

      Physical Review D74

      Pages: 043525

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Weighing neutrinos in the presence of a running primordial spectral index2006

    • Author(s)
      B.Feng, J.Xia, X.Zhang, G.Zhao, J.Yokoyama
    • Journal Title

      JCAP 0612

      Pages: 011

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Thermal background can solve the cosmological moduli problem2006

    • Author(s)
      横山順一
    • Journal Title

      Physical Review Letters 96

      Pages: 171301

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Gravitinos from heavy scalar decay2006

    • Author(s)
      T.Asaka, S.Nakamura, M. Yamaguchi
    • Journal Title

      Physical Review D74

      Pages: 023520

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Gravitino production from heavy moduli decay and cosmological moduli problem revived2006

    • Author(s)
      S.Nakamura, M.Yamaguchi
    • Journal Title

      Physics Letters B 638

      Pages: 389

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Power Spectrum of the Density Perturbations From Smooth Hybrid New Inflation Model2006

    • Author(s)
      M.Kawasaki, T.Takayama, M.Yamaguchi, J.Yokoyama
    • Journal Title

      Phys.Rev.D Vol.74

      Pages: 043525

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Weighing neutrinos in the presence of a running primordial spectral index2006

    • Author(s)
      B.Feng, J.Q.Xia, J.Yokoyama, X.Zhang, G.B.Zhao
    • Journal Title

      JCAP Vol.0612

      Pages: 011

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Thermal background can solve the cosmological moduli problem2006

    • Author(s)
      J.Yokoyama
    • Journal Title

      Phys.Rev.Lett. Vol.96

      Pages: 171301

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Gravitinos from heavy scalar decay2006

    • Author(s)
      T.Asaka, S.Nakamura, M.Yamaguchi
    • Journal Title

      Phys.Rev.D Vol.74

      Pages: 023520

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Gravitino production from heavy moduli decay and cosmological moduli problem revived2006

    • Author(s)
      S.Nakamura, M.Yamaguchi
    • Journal Title

      Phys.Lett.B Vol.638

      Pages: 389

    • Description
      「研究成果報告書概要(欧文)」より
  • [Book] 宇宙論I宇宙の始まり2008

    • Author(s)
      横山順一, ほか
    • Total Pages
      246
    • Publisher
      日本評論社
    • Description
      「研究成果報告書概要(和文)」より
  • [Book] Utyuuron I Utyuu no hajimari (in Japanese)2008

    • Author(s)
      J.Yokoyama, et al.
    • Total Pages
      1-203
    • Publisher
      Nihon Hyoron sya
    • Description
      「研究成果報告書概要(欧文)」より
  • [Book] 宇宙地球地震と火山2006

    • Author(s)
      木庭元晴、横山順一, ほか
    • Total Pages
      185
    • Publisher
      古今書院
    • Description
      「研究成果報告書概要(和文)」より
  • [Book] Utyuu Tikyuu Jishin to Kazan (in Japanese)2006

    • Author(s)
      M.Koba, J.Yokoyama, et al
    • Total Pages
      1-185
    • Publisher
      Kokon Shoin
    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2011-06-18  

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