Igata, T.   Ishihara, H.   Nishiwaki, K.   
Physical Review D - Particles, Fields, Gravitation and Cosmology 86(10) 2012年11月 [査読有り]
We investigate stationary rotating closed Nambu-Goto strings in five-dimensional flat spacetime. The stationary string is defined as a world sheet that is tangent to a timelike Killing vector. The Nambu-Goto equation of motion for the stationary s...
Igata, T.   Harada, T.   Kimura, M.   
Physical Review D - Particles, Fields, Gravitation and Cosmology 85(10) 2012年5月 [査読有り]
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 arbitrarily large center-of-mass (CM) energy. We demonstrate that the ...
Igata, T.   Koike, T.   Ishihara, H.   
Physical Review D - Particles, Fields, Gravitation and Cosmology 83(6) 2011年3月 [査読有り]
We discuss constants of motion of a particle under an external field in a curved spacetime, taking into account the Hamiltonian constraint, which arises from the reparametrization invariance of the particle orbit. As the necessary and sufficient c...
We study bound orbits of a free particle around a singly rotating black ring. We find there exists chaotic motion of a particle which is gravitationally bound to the black ring by using the Poincaré map.
We examine bound orbits of particles around singly rotating black rings. We show that there exist stable bound orbits in toroidal spiral shape near the "axis" of the ring, and also stable circular orbits on the axis as special cases. The stable bo...
Journal of Physics: Conference Series 314 012113-012113 2011年9月 [査読有り]
We study stable bound orbits of a free particle around a black ring. Unlike the higher-dimensional black hole case, we find that there exist stable bound orbits in toroidal spiral shape near the ring axis and stable circular orbits on the axis. In...