Roles of topological defects in the evolution of the universe

• Project/Area Number: 18740157
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Single-year Grants
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Aoyama Gakuin University
• Principal Investigator: YAMAGUCHI Masahide Aoyama Gakuin University, 理工学部, 准教授 (80383511)
• Project Period (FY): 2006 – 2007
• Project Status: Completed (Fiscal Year 2008)
• Budget Amount: ¥3,660,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥360,000); Fiscal Year 2008: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2007: ¥1,200,000 (Direct Cost: ¥1,200,000); Fiscal Year 2006: ¥900,000 (Direct Cost: ¥900,000)
• Keywords: 宇宙物理 / 位相的欠陥 / 揺らぎの非ガウス性 / バリオン数非対称性

Research Abstract

これまで行われてきたコスミックストリングの研究のほぼ全て、テンションは時間に依らないと仮定されてきた。しかしながら、振動する場との結合がある場合やブレインワールドモデルにおいては、一般にテンションは時間依存性を持つ。この新しいクラスのストリングに初めて着目し、宇宙における進化や構造形成への影響を議論した。また、超紐理論に基づいて提案されている宇宙に収縮時期があったとするシナリオにおいて、これまでの常識を覆し、コスミックストリングが最新の観測によって示唆されている密度揺らぎの性質を説明できる可能性があることを示した。

Research Products

• [Journal Article] Extended slow-roll conditions and primordial fluctuations : Multiple scalar fields and generalized gravity (2009)
  • Author(s): Takeshi Chiba and Masahide Yamaguchi
  • Journal Title: Journal of Cosmology and Astroparticle Physics 0901 Pages: 1-16
  • Peer Reviewed
• [Journal Article] Extended Slow-Roll Conditions and Primordial Fluctuations : Multiple Scalar Fields and Generalized Gravity (2009)
  • Author(s): T. Chiba, M. Yamaguchi
  • Journal Title: Journal of Cosmology and Astrophysics 01
  • Peer Reviewed
• [Journal Article] Reheating in chaotic D-term inflation (2008)
  • Author(s): Teruhiko Kawano and Masahide Yamaguchi
  • Journal Title: Physical Review D78 123511 Pages: 1-5
  • Peer Reviewed
• [Journal Article] Primordial curvature fluctuation and its non-Gaussianity in models with modulated reheating (2008)
  • Author(s): Kazuhide Ichikawa, Teruaki Suyama, Tomo Takahashi, and Masahide Yamaguchi
  • Journal Title: Physical Review D78 063545 Pages: 1-20
  • Peer Reviewed
• [Journal Article] Extended slow-roll conditions and rapid-roll conditions, (2008)
  • Author(s): Takeshi Chiba and Masahide Yamaguchi
  • Journal Title: Journal of Cosmology and Astroparticle Physics 0810 Pages: 1-16
  • Peer Reviewed
• [Journal Article] Non-Gaussianity, Spectral Index and Tensor Modes in Mixed Inflaton and Curvaton Models (2008)
  • Author(s): K. Ichikawa, T. Suyama, T. Takahashi, Masahide Yamaguchi
  • Journal Title: Physical Review D78 023513 Pages: 1-21
  • Peer Reviewed
• [Journal Article] New D-term chaotic inflation in supergravity and leptogenesis (2008)
  • Author(s): K. Kadota, T. Kawano, and Masahide Yamaguchi
  • Journal Title: Physical Review D77 123516 Pages: 1-8
  • Peer Reviewed
• [Journal Article] DBI-essence (2008)
  • Author(s): J. Martin and Masahide Yamaguchi
  • Journal Title: Physical Review D77 123508 Pages: 1-9
  • Peer Reviewed
• [Journal Article] Formation of intermediate-mass black holes as primordial black holes in the inflationary cosmology with running spectral index (2008)
  • Author(s): T. Kawaguchi, M. Kawasaki, T. Takayama, Masahide Yamaguchi, and J. Yokoyama
  • Journal Title: Monthly Notices of the Royal Astronomical Society 388 Pages: 1426-1432
  • Peer Reviewed
• [Journal Article] Non-Gaussianity in the modulated reheating scenario (2008)
  • Author(s): T. Suyama and Masahide Yamaguchi
  • Journal Title: Physical Review D77 023505 Pages: 1-8
  • Peer Reviewed
• [Journal Article] Reheating in Chaotic D-Term Inflation (2008)
  • Author(s): T. Kawano, M. Yamaguchi
  • Journal Title: Physical Review D78
  • Peer Reviewed
• [Journal Article] Primordial Curvature Fluctuation and Its Non-Gaussianity in Models with Modulated Reheating (2008)
  • Author(s): K. Ichikawa, T. Suyama, T. Takahashi, M. Yamaguchi
  • Journal Title: Physical Review D78
  • Peer Reviewed
• [Journal Article] Extended Slow-Roll Conditions and Rapid-Roll Conditions (2008)
  • Author(s): T. Chiba, M. Yamaguchi
  • Journal Title: Journal of Cosmology and Astrophysics 10
  • Peer Reviewed
• [Journal Article] Non-Gaussianity in the modulated reheating scenario (2008)
  • Author(s): T. Suyama, M. Yamaguchi
  • Journal Title: Physical Review D77
  • Peer Reviewed
• [Journal Article] D-term chaotic inflation in supergravity (2007)
  • Author(s): K. Kadota and Masahide Yamaguchi
  • Journal Title: Physical Review D76 103522 Pages: 1-5
  • Peer Reviewed
• [Journal Article] Effective Search Templates for a Primordial Stochastic Gravitational Wave Background (2007)
  • Author(s): T. Chiba, Y. Himemoto, Masahide Yamaguchi, and J. Yokoyama
  • Journal Title: Physical Review D76 043156 Pages: 1-7
  • Peer Reviewed
• [Journal Article] Warped Leptogenesis with Dirac Neutrino Masses (2007)
  • Author(s): T. Gherghetta, K. Kadota, and Masahide Yamaguchi
  • Journal Title: Physical Review D76 023516 Pages: 1-6
  • Peer Reviewed
• [Journal Article] Axino warm dark matter and Omega_b-Omega_DM coincidence, (2007)
  • Author(s): O. Seto and Masahide Yamaguchi
  • Journal Title: Physical Review D75 123506 Pages: 1-7
  • Peer Reviewed
• [Journal Article] Lepton asymmetry in the primordial gravitational wave spectrum (2007)
  • Author(s): K. Ichiki, Masahide Yamaguchi, and J. Yokoyama
  • Journal Title: Physical Review D75 084017 Pages: 1-8
  • Peer Reviewed
• [Journal Article] Electroweak Baryogenesis with Embedded Domain Walls (2007)
  • Author(s): R. H. Brandenberger, W. Kelly, and Masahide Yamaguchi
  • Journal Title: Progress of Theoretical Physics 117 Pages: 823-834
  • NAID: 110006278203
  • Peer Reviewed
• [Journal Article] Time variation of proton-electron mass ratio and fine structure constant with runaway dilaton (2007)
  • Author(s): T. Chiba, T. Kobayashi, Masahide Yamaguchi, and J. Yokoyama
  • Journal Title: Physical Review D75 043516 Pages: 1-10
  • Peer Reviewed
• [Journal Article] Axino warm dark matter and Omega_b-Omega_DM coincidence (2007)
  • Author(s): O. Seto, M. Yamaguchi
  • Journal Title: Physical Review D75
  • Peer Reviewed
• [Journal Article] Warped Leptogenesis with Dirac Neutrino Masses (2007)
  • Author(s): T. Gherghetta, K. Kadota, M.Yamaguchi
  • Journal Title: Physical Review D76
  • Peer Reviewed
• [Journal Article] Effective Search Templates for a Primordial Stochastic Gravitational Wave Background (2007)
  • Author(s): T. Chiba, Y. Himemoto, M. Yamaguchi, J. Yokoyama
  • Journal Title: Physical Review D76
  • Peer Reviewed
• [Journal Article] D-term chaotic inflation in supergravity (2007)
  • Author(s): K. Kadota, M. Yamaguchi
  • Journal Title: Physical Review D76
  • Peer Reviewed
• [Journal Article] Time variation of proton-electron mass ratio and fine structure constant with runaway dilaton (2007)
  • Author(s): T.Chiba, T.Kobayashi, M.Yamaguchi, J.Yokoyama
  • Journal Title: Physical Review D75 Pages: 43516-43516
• [Journal Article] Effects of Cosmic Strings on Free Streaming (2006)
  • Author(s): T. Takahashi and Masahide Yamaguchi
  • Journal Title: Physical Review D74 063512 Pages: 1-7
  • Peer Reviewed
• [Journal Article] Implications of cosmic strings with time-varying tension on CMB and large scale structure (2006)
  • Author(s): K. Ichikawa, T. Takahashi, and Masahide Yamaguchi
  • Journal Title: Physical Review D74 063526 Pages: 1-9
  • Peer Reviewed
• [Journal Article] Power spectrum of the density perturbations from smooth hybrid new inflation model (2006)
  • Author(s): M. Kawasaki, T. Takayama, Masahide Yamaguchi, and J. Yokoyama
  • Journal Title: Physical Review D74 043525 Pages: 1-10
  • Peer Reviewed
• [Journal Article] Power spectrum of the density perturbations from smooth hybrid new inflation model (2006)
  • Author(s): U.Kawasaki, T.Takayama, M.Yamaguchi, J.Yokoyama
  • Journal Title: Physical Review D74 Pages: 43525-43525
• [Journal Article] Implications of cosmic strings with time-varying tension on CMB and large scale structure (2006)
  • Author(s): K.Ichikawa, T.Takahashi, M.Yamaguchi
  • Journal Title: Physical Review D74 Pages: 63526-63526
• [Journal Article] Effects of Cosmic Strings on Free Streaming (2006)
  • Author(s): T.Takahashi, M.Yamaguchi
  • Journal Title: Physical Review D74 Pages: 63512-63512
• [Journal Article] Lepton asymmetry in the primordial gravitational wave spectrum
  • Author(s): K.Ichiki, M.Yamaguchi, J.Yokoyama
  • Journal Title: Physical Review (in press)