934 citations
- The University of TokyoJP492 papers
- Kyoto UniversityJP316 papers
- Centre National de la Recherche ScientifiqueFR275 papers
- Tokyo Institute of TechnologyJP265 papers
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- Institut National de Physique Nucléaire et de Physique des ParticulesFR239 papers
- RIKEN Nishina CenterJP216 papers
- High Energy Accelerator Research OrganizationJP213 papers
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6 papers · 2 filters
Signed magnification sums for general spherical lenses
Naoki Tsukamoto, Tomohiro Harada
It is well known that the sum of signed magnifications is invariant for mass lens systems. In this paper, we discuss the signed magnification sums of general spherical lens models…
Escape of superheavy and highly energetic particles produced by particle collisions near maximally charged black holes
Hiroya Nemoto, Umpei Miyamoto, Tomohiro Harada +1
For particle collision near rapidly rotating Kerr black holes, the center-of-mass energy can be arbitrarily high if the angular momentum of either of the colliding particles is fin…
Can we distinguish between black holes and wormholes by their Einstein-ring systems?
Naoki Tsukamoto, Tomohiro Harada, Kohji Yajima
For the last decade, the gravitational lensing in the strong gravitational field has been studied eagerly. It is well known that, for the lensing by a black hole, infinite number o…
Upper limits of particle emission from high-energy collision and reaction near a maximally rotating Kerr black hole
Tomohiro Harada, Hiroya Nemoto, Umpei Miyamoto
The center-of-mass energy of two particles colliding near the horizon of a maximally rotating black hole can be arbitrarily high if the angular momentum of either of the incident p…
Effect of a Weak Electromagnetic Field on Particle Acceleration by a Rotating Black Hole
Takahisa Igata, Tomohiro Harada, Masashi Kimura
We study high energy charged particle collisions near the horizon in an electromagnetic field around a rotating black hole and reveal the condition of the fine-tuning to obtain arb…
A No-Go Theorem for Rotating Stars of a Perfect Fluid without Radial Motion in Projectable Hořava--Lifshitz Gravity
Naoki Tsukamoto, Tomohiro Harada
Hořava--Lifshitz gravity has covariance only under the foliation-preserving diffeomorphism. This implies that the quantities on the constant-time hypersurfaces should be regular. I…