collaborators

9 papers

gr-qc2026

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…

gr-qc2026

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…

astro-ph.CO2026

Large -point Functions in Resonant Inflation

Paolo Creminelli, Sébastien Renaux-Petel, Giovanni Tambalo +1

We investigate a qualitatively new regime of inflationary models with small and rapid oscillations in the potential-resonant non-Gaussianity. In contrast to the standard scenario,…

hep-th2025

Beyond Coleman's Instantons

Misao Sasaki, Vicharit Yingcharoenrat, Ying-li Zhang

In the absence of gravity, Coleman's theorem states that the -symmetric instanton solution, which is regular at the origin and exponentially decays at infinity, gives the low…

gr-qc2025

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…

gr-qc2025

Effective Field Theory of Perturbations on Arbitrary Black Hole Backgrounds with Spacelike Scalar Profile

Shinji Mukohyama, Emeric Seraille, Kazufumi Takahashi +1

We develop the effective field theory (EFT) of perturbations in the context of scalar-tensor theories with a spacelike scalar profile on arbitrary black hole backgrounds. Our const…