15 citations · 26 across the 6 of their papers we have counts for
6 papers
Exact Cancellation of Horizon Modes in Kerr Ringdown
Kei-ichiro Kubota, Yusuke Manita, Hayato Motohashi +1
Ringdown gravitational waves probe black hole spacetimes via quasinormal modes (QNMs). Recent studies have reported oscillatory features in QNM-filtered waveforms, and have led to…
Pole Skipping, Avoided Crossing, and Resonant Excitation in Kerr Quasinormal Modes near Algebraically Special Frequencies
Kei-ichiro Kubota, Hayato Motohashi
Kerr quasinormal modes near algebraically special frequencies exhibit anomalous behavior, including apparent bifurcation, disappearance, and a nonsmooth connection to the Schwarzsc…
Ringdown analysis of GW250114 with orthonormal modes
Motoki Suzuki, Kei-ichiro Kubota, Soichiro Morisaki +2
GW250114 is the loudest gravitational wave event to date observed by LIGO-Virgo-KAGRA Collaboration. Owing to its high signal-to-noise ratio (SNR), previous analyses based on quasi…
Exceptional Points and Resonance in Black Hole Ringdown
Rodrigo Panosso Macedo, Takuya Katagiri, Kei-ichiro Kubota +1
We propose an exceptional-point (EP) framework for black-hole ringdown beyond the standard quasinormal-mode (QNM) paradigm. It provides a first-principles characterization of the r…
Resonance in black hole ringdown: Benchmarking quasinormal mode excitation and extraction
Kei-ichiro Kubota, Hayato Motohashi
We investigate how resonant excitation near exceptional points manifests in Kerr black hole ringdown waveforms and examine its extraction. Using waveforms generated by localized in…
Spin wave optics for gravitational waves lensed by a Kerr black hole
Kei-ichiro Kubota, Shun Arai, Hayato Motohashi +1
Gravitational waves exhibit the unique signature of their spin-2 nature in processes of wave scattering, due to the interaction between spin and a background spacetime. Since the s…