5 papers
Can Horndeski Genesis be Nonpathological?
Han Gil Choi, Pavel Petrov, Masahide Yamaguchi
We present a minimal setup within the framework of Horndeski gravity that can describe a nonpathological Genesis scenario. Our setup allows for a fully stable transition to the kin…
Gravitational mode mixing around black holes in scalar-tensor theories with parity-violating terms
Shin'ichi Hirano, Masashi Kimura, Masahide Yamaguchi
We investigate black holes and gravitational perturbations when both the scalar Gauss-Bonnet and dynamical Chern-Simons gravity sectors coexist in addition to the Einstein-Hilbert…
Trace Anomaly in Metric-Affine gravity
Sebastian Bahamonde, Yuichi Miyashita, Masahide Yamaguchi
We explore the trace (Weyl) anomaly within a general metric-affine geometry that includes both torsion and nonmetricity. Using the Heat Kernel method and Seeley's algorithm, we com…
Parametrized Black Hole Quasinormal Ringdown Formalism for Higher Overtones
Shin'ichi Hirano, Masashi Kimura, Masahide Yamaguchi +1
We investigate the parametrized black hole quasinormal ringdown formalism, which is a robust framework used to analyze quasinormal modes in systems that closely resemble general re…
Generalisation of Conformal-Disformal Transformations of the Metric in Scalar-Tensor Theories
Eugeny Babichev, Keisuke Izumi, Karim Noui +2
We study new classes of metric transformations in the context of scalar-tensor theories, which involve both higher derivatives of the scalar field and derivatives of the metric its…