199 citations · 4.2k across the 135 of their papers we have counts for
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Increasing Temperature toward the Completion of Reheating
Raymond T. Co, Eric Gonzalez, Keisuke Harigaya
Reheating is a process where the energy density of a dominant component of the universe other than radiation, such as a matter component, is transferred into radiation. It is usual…
Common Origin of Warm Dark Matter and Dark Radiation
Manuel A. Buen-Abad, Raymond T. Co, Keisuke Harigaya
We consider a cosmological scenario where a relativistic particle and a stable massive particle are simultaneously produced from the decay of a late-decaying particle after Big-Ban…
New Inflation in the Landscape and Typicality of the Observed Cosmic Perturbation
Chien-I Chiang, Keisuke Harigaya
We investigate if the observed small and nearly scale-invariant primordial cosmic perturbation, i.e. the perturbation amplitude and the spectral index $n_s \simeq…
Hubble induced mass after inflation in spectator field models
Tomohiro Fujita, Keisuke Harigaya
Spectator field models such as the curvaton scenario and the modulated reheating are attractive scenarios for the generation of the cosmic curvature perturbation, as the constraint…
Baryon Asymmetry, Dark Matter, and Density Perturbation from PBH
Tomohiro Fujita, Keisuke Harigaya, Masahiro Kawasaki +1
We investigate the consistency of a scenario in which the baryon asymmetry, dark matters, as well as the cosmic density perturbation are generated simultaneously through the evapor…
Large Scale Cosmic Perturbation from Evaporation of Primordial Black Holes
Tomohiro Fujita, Keisuke Harigaya, Masahiro Kawasaki
We present a novel mechanism to generate the cosmic perturbation from evaporation of primordial black holes. A mass of a field is fluctuated if it is given by a vacuum expectation…