83 citations · 400 across the 18 of their papers we have counts for
4 papers · 1 filter
Gravitational positivity bounds
Junsei Tokuda, Katsuki Aoki, Shin'ichi Hirano
We study the validity of positivity bounds in the presence of a massless graviton, assuming the Regge behavior of the amplitude. Under this assumption, the problematic -channel…
UV sensitive one-loop matter power spectrum in degenerate higher-order scalar-tensor theories
Shin'ichi Hirano, Tsutomu Kobayashi, Daisuke Yamauchi +1
We study matter density perturbations up to third order and the one-loop matter power spectrum in degenerate higher-order scalar-tensor (DHOST) theories beyond Horndeski. We system…
Abundance of Primordial Black Holes in Peak Theory for an Arbitrary Power Spectrum
Chul-Moon Yoo, Tomohiro Harada, Shin'ichi Hirano +1
We modify the procedure to estimate PBH abundance proposed in arXiv:1805.03946 so that it can be applied to a broad power spectrum such as the scale-invariant flat power spectrum.…
Primordial tensor non-Gaussianities from general single-field inflation with non-Bunch-Davies initial states
Shingo Akama, Shin'ichi Hirano, Tsutomu Kobayashi
It has been found that the primordial non-Gaussianity of the curvature perturbation in the case of non-Bunch-Davies initial states can be enhanced compared with those in the case o…