117 citations · 1k across the 40 of their papers we have counts for
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Gravitational scalar-tensor theory
Atsushi Naruko, Daisuke Yoshida, Shinji Mukohyama
We consider a new form of theories of gravity in which the action is written in terms of the Ricci scalar and its first and second derivatives. Despite the higher derivative nature…
Derivative-dependent metric transformation and physical degrees of freedom
Guillem Domènech, Shinji Mukohyama, Ryo Namba +3
We study metric transformations which depend on a scalar field and its first derivatives and confirm that the number of physical degrees of freedom does not change under such t…
Cosmological disformal invariance
Guillem Domènech, Atsushi Naruko, Misao Sasaki
The invariance of physical observables under disformal transformations is considered. It is known that conformal transformations leave physical observables invariant. However, whet…
Multi-disformal invariance of nonlinear primordial perturbations
Yuki Watanabe, Atsushi Naruko, Misao Sasaki
We study disformal transformations of the metric in the cosmological context. We first consider the disformal transformation generated by a scalar field and show that the curva…
Probing small-scale non-Gaussianity from anisotropies in acoustic reheating
Atsushi Naruko, Atsuhisa Ota, Masahide Yamaguchi
We give new constraints on small-scale non-Gaussianity of primordial curvature perturbations by the use of anisotropies in acoustic reheating. Mixing of local thermal or local kine…