683 citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- Tohoku UniversityJP202 papers
- The University of TokyoJP78 papers
- Kyoto UniversityJP59 papers
- National Astronomical Observatory of JapanJP44 papers
- Kavli Institute for the Physics and Mathematics of the UniverseJP40 papers
- Nagoya UniversityJP33 papers
- The University of OsakaJP32 papers
- Massachusetts Institute of TechnologyUS30 papers
- Institute of Space and Astronautical ScienceJP27 papers
- Japan Aerospace Exploration AgencyJP26 papers
- Ehime UniversityJP24 papers
- Institute of Astronomy and Astrophysics, Academia SinicaTW24 papers
36 papers · 1 filter
Trapping Effect for QCD Axion Dark Matter
Shota Nakagawa, Fuminobu Takahashi, Masaki Yamada
In the early universe, the potential of a scalar field can be significantly modified, and the scalar field may be trapped for a long time in a different location than the current v…
Nano-Hz gravitational wave signature from axion dark matter
Naoya Kitajima, Jiro Soda, Yuko Urakawa
We calculate the accurate spectrum of the stochastic gravitational wave background from U(1) gauge fields produced by axion dark matter. The explosive production of gauge fields so…
Spin injection characteristics of Py/graphene/Pt by gigahertz and terahertz magnetization dynamics driven by femtosecond laser pulse
H. Idzuchi, S. Iihama, M. Shimura +3
Spin transport characteristics of graphene has been extensively studied so far. The spin transport along c-axis is however reported by rather limited number of papers. We have stud…
No-go theorem of anisotropic inflation via Schwinger mechanism
Hiroyuki Kitamoto
In the presence of a dilatonic coupling between an inflaton and a gauge field, a persistent electric field (i.e., an anisotropic inflation) is obtained as a solution of the…
Interface-induced field-like optical spin torque in a ferromagnet/heavy metal heterostructure
Satoshi Iihama, Kazuaki Ishibashi, Shigemi Mizukami
The manipulation of magnetization in a metallic ferromagnet by using optical helicity has been much attracted attention for future opto-spintronic devices. The optical helicity ind…
Gravitational Waves and Dark Radiation from Dark Phase Transition: Connecting NANOGrav Pulsar Timing Data and Hubble Tension
Yuichiro Nakai, Motoo Suzuki, Fuminobu Takahashi +1
Recent pulsar timing data reported by the NANOGrav collaboration may indicate the existence of a stochastic gravitational wave background around Hz. We explore a p…
High-energy neutrino emission subsequent to gravitational wave radiation from supermassive black hole mergers
Chengchao Yuan, Kohta Murase, Shigeo S. Kimura +1
Supermassive black hole (SMBH) coalescences are ubiquitous in the history of the Universe and often exhibit strong accretion activities and powerful jets. These SMBH mergers are al…
A Jet-Bases Emission Model of the EHT 2017 Image of M87*
Tomohisa Kawashima, Kenji Toma, Motoki Kino +3
We carry out general relativistic ray-tracing radiative-transfer calculations to study whether a localized emission from plasma rings created at the stagnation surface in…
Necessary and sufficient condition for hysteresis in the mathematical model of the cell type regulation of \textit{Bacillus subtilis}
Sohei Tasaki, Madoka Nakayama, Izumi Takagi +2
The key to a robust life system is to ensure that each cell population is maintained in an appropriate state. In this work, a mathematical model was used to investigate the control…
Electromechanical properties of ferroelectric polymers: Finsler geometry modeling and a Monte Carlo study
V. Egorov, O. Maksimova, H. Koibuchi +7
Polyvinylidene difluoride (PVDF) is a ferroelectric polymer characterized by negative strain along the direction of the applied electric field. However, the electromechanical respo…
Comprehensive analysis of magnetospheric gaps around Kerr black holes using 1D GRPIC simulations
Shota Kisaka, Amir Levinson, Kenji Toma
Spark gaps are likely the source of plasma in active black hole (BH) magnetospheres. In this paper, we present results of 1D general-relativistic particle-in-cell simulations of a…
Mechanical Quantum Sensing in the Search for Dark Matter
Daniel Carney, Gordan Krnjaic, David C. Moore +32
Numerous astrophysical and cosmological observations are best explained by the existence of dark matter, a mass density which interacts only very weakly with visible, baryonic matt…
Deciphering the Origin of the GeV--TeV Gamma-ray Emission from SS 433
Shigeo S. Kimura, Kohta Murase, Peter Mészáros
We investigate hadronic and leptonic scenarios for the GeV--TeV gamma-ray emission from jets of the microquasar SS 433. The emission region of the TeV photons coincides with the X-…
An agent-based model for interrelation between COVID-19 outbreak and economic activities
Takeshi Kano, Kotaro Yasui, Taishi Mikami +2
As of July, 2020, acute respiratory syndrome caused by coronavirus COVID-19 is spreading over the world and causing severe economic damages. While minimizing human contact is effec…
What if ALP dark matter for the XENON1T excess is the inflaton
Fuminobu Takahashi, Masaki Yamada, Wen Yin
The recent XENON1T excess in the electron recoil data can be explained by anomaly-free axion-like particle (ALP) dark matter with mass keV and the decay constan…
Branching process descriptions of information cascades on Twitter
James P. Gleeson, Tomokatsu Onaga, Peter Fennell +3
A detailed analysis of Twitter-based information cascades is performed, and it is demonstrated that branching process hypotheses are approximately satisfied. Using a branching proc…
Probing Particle Acceleration through Broadband Early Afterglow Emission of MAGIC Gamma-Ray Burst GRB 190114C
Katsuaki Asano, Kohta Murase, Kenji Toma
Major Atmospheric Gamma Imaging Cherenkov Telescopes (MAGIC) detected the gamma-ray afterglow of GRB 190114C, which can constrain microscopic parameters of the shock-heated plasma…
Determination of the phase coherence length of PdCoO nanostructures
T. Harada, P. Bredol, H. Inoue +3
The two-dimensional layered compound PdCoO is one of the best oxide conductors, providing an intriguing research arena opened by the long mean free path and the very high mobil…
Primordial Black Holes from QCD Axion Bubbles
Naoya Kitajima, Fuminobu Takahashi
We propose a scenario in which a strong Peccei-Quinn (PQ) symmetry breaking in the early universe results in large inhomogeneities of the initial QCD axion field value, leading to…
XENON1T excess from anomaly-free ALP dark matter and its implications for stellar cooling anomaly
Fuminobu Takahashi, Masaki Yamada, Wen Yin
Recently, an anomalous excess was found in the electronic recoil data collected at the XENON1T experiment. The excess may be explained by an axion-like particle (ALP) with mass of…
High-Energy Neutrino and Gamma-Ray Emission from Tidal Disruption Events
Kohta Murase, Shigeo S. Kimura, B. Theodore Zhang +2
Tidal disruption events (TDE) have been considered as cosmic-ray and neutrino sources for a decade. We suggest two classes of new scenarios for high-energy multi-messenger emission…
Multi-Wave band Synchrotron Polarization of Gamma-Ray Burst Afterglows
Jiro Shimoda, Kenji Toma
Multi-wave band synchrotron linear polarization of gamma-ray burst (GRB) afterglows is studied under the assumption of an anisotropic turbulent magnetic field with a coherence leng…
Soft gamma rays from low accreting supermassive black holes and connection to energetic neutrinos
Shigeo S. Kimura, Kohta Murase, Peter Mészáros
The Universe is filled with a diffuse background of MeV gamma-rays and PeV neutrinos, whose origins are unknown. Here, we propose a scenario that can account for both backgrounds s…
Auroral diagnosis of solar wind interaction with Jupiter's magnetosphere
Z. H. Yao, B. Bonfond, D. Grodent +11
Although mass and energy in Jupiter's magnetosphere mostly come from the innermost Galilean moon Io's volcanic activities, solar wind perturbations can play crucial roles in releas…