10 papers
The Challenge of Detecting Quantum Nature of Gravitational Waves
Yu Miyauchi, Hidetoshi Omiya, Atsuhisa Ota +2
We investigate whether squeezing can provide an observable signature of quantum gravitational waves. Because a realistic detector couples only to a particular wave-packet mode, squ…
Reflection polarization of close binaries as a probe of axion dark matter birefringence
Tomoki Matsuoka, Kimihiro Nomura, Hidetoshi Omiya
We propose close binary polarimetry as a probe of birefringence induced by ultralight axion dark matter. In a close binary, reflection or scattering can generate a small linear pol…
Spectral instability of parametrized black hole quasinormal modes in the high-overtone limit via the exact WKB analysis
Taiga Miyachi, Ryo Namba, Hidetoshi Omiya +1
We study the asymptotic behavior of parametrized black hole quasinormal modes (QNMs) in the high-overtone limit. To gain insights into their analytical structure, we apply the exac…
Detecting Parity-Violating Gravitational Wave Backgrounds with Pulsar Polarization Arrays
Qiuyue Liang, Kimihiro Nomura, Hidetoshi Omiya
Pulsar timing arrays probe isotropic stochastic gravitational wave (GW) backgrounds in the nanohertz band but are insensitive to its parity-violating component. Motivated by recent…
Signature of polarized ultralight vector dark matter in pulsar timing arrays
Kimihiro Nomura, Hidetoshi Omiya, Takahiro Tanaka
We investigate observational signatures of ultralight vector dark matter with masses - eV in pulsar timing arrays, taking into account general polarizati…
Quantum Treatment of Black Hole Superradiance
Lingyun Fu, Hidetoshi Omiya, Takahiro Tanaka +3
Rotating black holes can form dense boson clouds through superradiant instability, making Kerr black holes a powerful probe of ultralight massive bosons. Previous studies of black…