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Physically consistent gravitational waveform for capturing beyond general relativity effects in the compact object merger phase
Daiki Watarai, Atsushi Nishizawa, Kipp Cannon
The merger phase of compact binary coalescences is the strongest gravity regime that can be observed. To test the validity of general relativity (GR) in strong gravitational fields…
Distinguishing a stochastic gravitational-wave signal from correlated noise with joint parameter estimation: Fisher analysis for ground-based detectors
Yoshiaki Himemoto, Atsushi Nishizawa, Atsushi Taruya
Search sensitivity to a stochastic gravitational-wave background (SGWB) is enhanced by cross-correlating detector signals. However, one of the most serious concerns is the environm…
Displacement-noise-free interferometeric gravitational-wave detector using unidirectional neutrons with four speeds
Shoki Iwaguchi, Atsushi Nishizawa, Yanbei Chen +11
For further gravitational wave (GW) detections, it is significant to invent a technique to reduce all kinds of mirror displacement noise dominant at low frequencies for ground-base…
Observational constraint on axion dark matter with gravitational waves
Takuya Tsutsui, Atsushi Nishizawa
Most matter in the Universe is invisible and unknown, which is called dark matter. A candidate of dark matter is axion, which is an ultra-light particle motivated as a solution for…
Displacement-noise-free neutron interferometer for gravitational wave detection using a single Mach-Zehnder configuration
Shoki Iwaguchi, Atsushi Nishizawa, Yanbei Chen +10
The improvement of sensitivity to gravitational waves (GWs) at lower frequencies is still challenging on account of displacement noise. One of the solutions is the neutron displace…
Neutron displacement noise-free interferometer for gravitational-wave detection
Atsushi Nishizawa, Shoki Iwaguchi, Yanbei Chen +10
An interferometer design that cancels all displacement noises of its test masses and maintains a gravitational-wave (GW) signal by combining multiple detector signals is called a d…
Early warning of precessing neutron-star black-hole binary mergers with the near-future gravitational-wave detectors
Takuya Tsutsui, Atsushi Nishizawa, Soichiro Morisaki
Since gravitational and electromagnetic waves from a compact binary coalescence carry independent information about the source, the joint observation is important for understanding…
Scalar-tensor mixed polarization search of gravitational waves
Hiroki Takeda, Soichiro Morisaki, Atsushi Nishizawa
An additional scalar degree of freedom for a gravitational wave is often predicted in theories of gravity beyond general relativity and can be used for a model-agnostic test of gra…
Gravitational Wave Physics and Astronomy in the nascent era
Makoto Arimoto, Hideki Asada, Michael L. Cherry +50
The detections of gravitational waves (GW) by LIGO/Virgo collaborations provide various possibilities to physics and astronomy. We are quite sure that GW observations will develop…
Impacts of overlapping gravitational-wave signals on the parameter estimation: Toward the search for cosmological backgrounds
Yoshiaki Himemoto, Atsushi Nishizawa, Atsushi Taruya
Third-generation gravitational wave detectors, such as the Einstein Telescope and Cosmic Explorer, will detect a bunch of gravitational-wave (GW) signals originating from the coale…
Reduction of quantum noise using the quantum locking with an optical spring for gravitational wave detectors
Rika Yamada, Yutaro Enomoto, Izumi Watanabe +11
In our previous research, simulation showed that a quantum locking scheme with homodyne detection in sub-cavities is effective in surpassing the quantum noise limit for Deci-hertz…
Early warning of precessing compact binary merger with third-generation gravitational-wave detectors
Takuya Tsutsui, Atsushi Nishizawa, Soichiro Morisaki
Rapid localization of gravitational-wave events is important for the success of the multi-messenger observations. The forthcoming improvements and constructions of gravitational-wa…
Pure polarization test of GW170814 and GW170817 using waveforms consistent with modified theories of gravity
Hiroki Takeda, Soichiro Morisaki, Atsushi Nishizawa
The physical degrees of freedom of a gravitational wave (GW) are imprints of the nature of gravity. We can test a gravity theory by searching for polarization modes beyond general…
Overview of KAGRA : KAGRA science
KAGRA Collaboration, T. Akutsu, M. Ando +240
KAGRA is a newly build gravitational-wave observatory, a laser interferometer with 3 km arm length, located in Kamioka, Gifu, Japan. In this paper in the series of KAGRA-featured a…
Prospects for improving the sensitivity of the cryogenic gravitational wave detector KAGRA
Yuta Michimura, Kentaro Komori, Yutaro Enomoto +18
Upgrades to improve the sensitivity of gravitational wave detectors enable more frequent detections and more precise source parameter estimation. Unlike other advanced interferomet…
Optimization of quantum noise by completing the square of multiple interferometer outputs in quantum locking for gravitational wave detectors
Rika Yamada, Yutaro Enomoto, Atsushi Nishizawa +11
The quantum locking technique, which uses additional short low-loss sub-cavities, is effective in reducing quantum noise in space gravitational wave antenna DECIGO. However, the qu…
Cosmological evolution of viable models in the generalized scalar-tensor theory
Shun Arai, Purnendu Karmakar, Atsushi Nishizawa
We investigate the parameter distributions of the viable generalized scalar-tensor theory with conventional dust matter after GW170817 in a model-independent way. We numerically co…
Prospects for improving the sensitivity of KAGRA gravitational wave detector
Yuta Michimura, Masaki Ando, Eleonora Capocasa +22
KAGRA is a new gravitational wave detector which aims to begin joint observation with Advanced LIGO and Advanced Virgo from late 2019. Here, we present KAGRA's possible upgrade pla…
Convergence of Fourier-domain templates for inspiraling eccentric compact binaries
Sashwat Tanay, Antoine Klein, Emanuele Berti +1
The space-based detector LISA may observe gravitational waves from the early inspiral of stellar-mass black hole binaries, some of which could have significant eccentricity. Curren…
Prospects for gravitational-wave polarization test from compact binary mergers with future ground-based detectors
Hiroki Takeda, Atsushi Nishizawa, Koji Nagano +4
There exist six possible polarization modes of gravitational waves in general metric theory of gravity, while two tensor polarization modes are allowed in general relativity. The p…
Constraining extra gravitational wave polarizations with Advanced LIGO, Advanced Virgo and KAGRA and upper bounds from GW170817
Yuki Hagihara, Naoya Era, Daisuke Iikawa +2
General metric theories of gravity in four-dimensional spacetimes can contain at most six polarization modes (two spin-0, two spin-1 and two spin-2) of gravitational waves (GWs). I…
Generalized framework for testing gravity with gravitational-wave propagation. III. Future prospect
Atsushi Nishizawa, Shun Arai
The properties of gravitational-wave (GW) propagation are modified in alternative theories of gravity and are crucial observables to test gravity at cosmological distance. The prop…
KAGRA: 2.5 Generation Interferometric Gravitational Wave Detector
T. Akutsu, M. Ando, K. Arai +188
The recent detections of gravitational waves (GWs) reported by LIGO/Virgo collaborations have made significant impact on physics and astronomy. A global network of GW detectors wil…
Parity-violating gravity and GW170817
Atsushi Nishizawa, Tsutomu Kobayashi
We consider gravitational waves (GWs) in generic parity-violating gravity including recently proposed ghost-free theories with parity violation as well as Chern-Simons (CS) modifie…