Cosmophysics Group Seminar



$ Misao Sasaki「Scalaron as a Heavy Field and Formation of Primordial Black Holes」

$ Abstract: We propose a model of two-stage inflation in which a scalar field, chi, is non-minimally coupled to Starobinsky's R2 gravity. The scalaron, phi, in Starobinsky’ model drives the first stage of inflation, and chi drives the second. At the end of the first stage, the scalaron becomes heavy and undergoes damped oscillations. This causes enhancement and oscillatory features in the curvature perturbation power spectrum. The peak in these features may give rise to copious production of primordial black holes (PBHs). For a suitably chosen set of model parameters, these PBHs may even dominate the CDM of the Universe.
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Takahiko Matsubara「The Large-scale Structure and the Lagrangian Perturbation Theory」

Abstract: The Lagrangian perturbation theory (LPT) is an alternative method of perturbation theory for the cosmologically nonlinear structure formation. In this talk, I will introduce a formulation dubbed integrated Perturbation Theory (iPT), which is based on the LPT, and present its consequences in correlation analyses of galaxy surveys.

Past Cosmophysics Group Seminar

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