334 citations · 4k across the 75 of their papers we have counts for
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Ultra Slow-Roll Inflation and the non-Gaussianity Consistency Relation
Jerome Martin, Hayato Motohashi, Teruaki Suyama
Ultra slow-roll inflation has recently been used to challenge the non-Gaussianity consistency relation. We show that this inflationary scenario belongs to a one parameter class of…
Consequences of a stochastic approach to the conformal invariance of inflationary correlators
Hayato Motohashi, Teruaki Suyama, Jun'ichi Yokoyama
We provide a general formalism to calculate the infrared correlators of multiple interacting scalar fields in the de Sitter space by means of the stochastic approach. These scalar…
Self-accelerating solutions in massive gravity on an isotropic reference metric
Hayato Motohashi, Teruaki Suyama
Within the framework of the recently proposed ghost-free massive gravity, a cosmological constant-type self-accelerating solution has been obtained for Minkowski and de Sitter refe…
Reheating after f(R) inflation
Hayato Motohashi, Atsushi Nishizawa
The reheating dynamics after the inflation induced by -corrected model is considered. To avoid the complexity of solving the fourth order equations, we analyze the infl…
Cosmology Based on f(R) Gravity Admits 1 eV Sterile Neutrinos
Hayato Motohashi, Alexei A. Starobinsky, Jun'ichi Yokoyama
It is shown that the tension between recent neutrino oscillation experiments, favoring sterile neutrinos with masses of the order of 1 eV, and cosmological data which impose string…
Black hole perturbation in the most general scalar-tensor theory with second-order field equations I: The odd-parity sector
Tsutomu Kobayashi, Hayato Motohashi, Teruaki Suyama
We perform a fully relativistic analysis of odd-type linear perturbations around a static and spherically symmetric solution in the most general scalar-tensor theory with second-or…