7 citations · 10 across the 17 of their papers we have counts for
18 papers
Simulation of PBH formation in a matter-dominated universe
Chul-Moon Yoo, Albert Escrivà, Tomohiro Harada +1
We investigate primordial black hole (PBH) formation during an early matter-dominated era using fully nonlinear numerical relativity. The initial condition is set by a functional f…
Higher-Order Analytical Expansion of Thawing Dark Energy with an Exponential Potential
Naoto Maki, Kazunori Kohri
Motivated by recent DESI results suggesting dynamical dark energy, we investigate the thawing scenario in quintessence with an exponential potential, …
X-ray signals converted from high-frequency gravitational waves emitted by spinning light primordial black hole dark matter
Asuka Ito, Kazunori Kohri
We investigate the detectability of high-frequency gravitational waves from the superradiance of light primordial black hole dark matter through photons converted in the Galactic m…
A cross-calibration approach for polarisation-sensitive detectors in CMB experiments: application to LiteBIRD's polarisation angle calibration
A. Novelli, F. Piacentini, S. Micheli +102
We present a cross-calibration algorithm that determines the relative calibration of detectors within the same frequency band of a CMB experiment. The method iteratively compares s…
Graviton Floor
Himeka Matsuo, Asuka Ito, Kazunori Kohri +2
It has been observed that the Universe is permeated by the cosmic photon background, ranging from radio waves to gamma rays. We investigate the conversion of the photon background…
Natural Inflation with a negative cosmological constant
Chia-Min Lin, Naoto Maki, Kazunori Kohri
In this work, we investigate a cosmic inflation model based on a cosine-type potential with a negative cosmological constant. This model originates from a classical solution of the…
Gravitational wave emission from nonspherical collapse in an early matter-dominated era using N-body simulations
Albert Escrivà, Tomohiro Harada, Kazunori Kohri +2
We study the dynamics of the collapse of a nonspherical overdense patch during an early matter-dominated era and the associated production of gravitational waves (GWs) using a semi…
Blue-tilted spectral running and the JWST early galaxy tension
Mikage U. Kobayashi, Gen Chiaki, Kazutaka Kimura +4
Recently, the James Webb Space Telescope (JWST) collaboration has found the unexpectedly large abundance of massive galaxies with stellar masses of at high…
Exponential Quintessence: Analytic Relationship Between the Current Equation of State Parameter and the Potential Parameter
Naoto Maki, Kazunori Kohri
Motivated by the indications of time-varying dark energy equation of state reported from DESI, we investigate a quintessence model with an exponential potential $V_0 e^{-λϕ/m_{\mat…
Simple Analytical Solutions of the Wheeler-DeWitt Equation in the Classical Hamilton-Jacobi Limit
Naoto Maki, Chia-Min Lin, Kazunori Kohri
We investigate the Wheeler-DeWitt equation for a flat, homogeneous, and isotropic Universe containing a canonical scalar field with a potential. We show that under the constraint $…
CMB signatures of gravity-mediated dark radiation in
Anish Ghoshal, Sk Jeesun, Kazunori Kohri
Measurement of in the CMB (Cosmic Microwave Background) observations, like Planck 2018 and BBN (Big Bang Nucleosynthesis) has already set stringent constraints on the…
Exponential Quintessence Model: Analytical Quantification of the Fine-Tuning Problem in Dark Energy
Naoto Maki, Kazunori Kohri
In this paper, we investigate a quintessence field with an exponential potential motivated by the suggestion of time-varying dark energy from the DESI galaxy survey. Assuming a kin…
NANOGrav 15-year gravitational-wave signals from binary supermassive black-holes seeded by primordial black holes, and implications for the origins of Little Red Dots
Mikage U. Kobayashi, Kazunori Kohri
In this paper, we explain the recently reported a nHz-band gravitational-wave background from NANOGrav 15-year through the merger of binary super-massive black holes with masses of…
Primordial Black Hole Formation and Spin in Matter Domination Revisited
Weitao Ye, Yungui Gong, Tomohiro Harada +4
In this article, we calculate the mass distribution of primordial black holes (PBHs) formed in the matter-dominated (MD) era by the peak theory. We apply the Zel'dovich approximati…
Isotropy, anisotropies and non-Gaussianity in the scalar-induced gravitational-wave background: diagrammatic approach for primordial non-Gaussianity up to arbitrary order
Jun-Peng Li, Sai Wang, Zhi-Chao Zhao +1
Produced nonlinearly by the enhanced linear cosmological curvature perturbations, the scalar-induced gravitational waves (SIGWs) can serve as a potentially powerful probe of primor…
General relativistic effects on photon spectrum emitted from dark matter halos around primordial black holes
Toya Suzuki, Takahisa Igata, Kazunori Kohri +1
We investigate general relativistic effects on the photon spectrum emitted from decaying (or annihilating) particle dark matter in the halo surrounding a primordial black hole. The…
Study of primordial non-Gaussianity and with the cross-correlations between the scalar-induced gravitational waves and the cosmic microwave background
Zhi-Chao Zhao, Sai Wang, Jun-Peng Li +1
The stochastic gravitational-wave background originating from cosmic sources contains vital information about the early universe. In this work, we comprehensively study the cross-c…
Thermalization and hotspot formation around small primordial black holes
Minxi He, Kazunori Kohri, Kyohei Mukaida +1
We quantitatively analyze a basic question: what is the stationary solution of the background plasma temperature profile around a black hole (BH)? One may naively expect that the t…