96 citations · 1.2k across the 37 of their papers we have counts for
6 papers · 2 filters
Exact solution for rotating black holes in parity-violating gravity
Hiroaki W. H. Tahara, Kazufumi Takahashi, Masato Minamitsuji +1
It has recently been pointed out that one can construct invertible conformal transformations with a parity-violating conformal factor, which can be employed to generate a novel cla…
Black hole ringdown from physically sensible initial value problem in higher-order scalar-tensor theories
Keisuke Nakashi, Masashi Kimura, Hayato Motohashi +1
We study odd-parity perturbations about static and spherically symmetric black hole solutions with a linearly time-dependent scalar field in higher-order scalar-tensor theories. In…
Invertible disformal transformations with arbitrary higher-order derivatives
Kazufumi Takahashi
Invertible disformal transformations serve as a useful tool to explore ghost-free scalar-tensor theories. In this paper, we construct a generalization of invertible disformal trans…
Quasinormal Modes from EFT of Black Hole Perturbations with Timelike Scalar Profile
Shinji Mukohyama, Kazufumi Takahashi, Keitaro Tomikawa +1
The Effective Field Theory (EFT) of perturbations on an arbitrary background geometry with a timelike scalar profile was recently constructed in the context of scalar-tensor theori…
Effective description of generalized disformal theories
Kazufumi Takahashi, Masato Minamitsuji, Hayato Motohashi
Generalized disformal transformations enable us to construct the generalized disformal Horndeski theories, which form the most general class of ghost-free scalar-tensor theories to…
Consistency of higher derivative couplings to matter fields in scalar-tensor gravity
Tact Ikeda, Kazufumi Takahashi, Tsutomu Kobayashi
Recently, a generalization of invertible disformal transformations containing higher-order derivatives of a scalar field has been proposed in the context of scalar-tensor theories…