11 papers
Inverting no-hair theorems: How requiring General Relativity solutions restricts scalar-tensor theories
Hajime Kobayashi, Shinji Mukohyama, Johannes Noller +3
Black hole solutions in general scalar-tensor theories are known to permit hair, i.e. non-trivial scalar profiles and/or metric solutions different from the ones of General Relativ…
Dynamical Tidal Response of Non-rotating Black Holes: Connecting the MST Formalism and Worldline EFT
Hajime Kobayashi, Shinji Mukohyama, Naritaka Oshita +2
The response of a black hole (BH) to tidal forces encodes key information about the underlying gravitational theory and affects the waveform of gravitational waves emitted during b…
Cosmological perturbation theory with trinity of scalar fields
Amjad Ashoorioon, Shinji Mukohyama, Kazem Rezazadeh +1
We present an explicit formulation of cosmological perturbation theory for three-field models with a flat field space. By performing rotations to align one field with the direction…
Quasinormal Modes from EFT of Black Hole Perturbations in Vector-Tensor Gravity
Shogo Tomizuka, Hajime Kobayashi, Naritaka Oshita +2
We study the dynamics of odd-parity perturbations on a static and spherically symmetric black hole background with a timelike vector field based on the effective field theory (EFT)…
Parametrized Tidal Dissipation Numbers of Non-rotating Black Holes
Hajime Kobayashi, Shinji Mukohyama, Naritaka Oshita +2
A set of tidal dissipation numbers (TDNs) quantifies the absorption of the tidal force exerted by a companion during an inspiralling phase of a binary compact object. This tidal di…
Exorcising ghosts with gravitational waves: cases of ghostful and ghost-free fourth-order gravity
Gaetano Lambiase, Shinji Mukohyama, Tanmay Kumar Poddar +1
General Relativity (GR) is an effective field theory valid in the infrared regime. Quadratic curvature extensions intended to probe ultraviolet physics generically propagate a mass…