20 citations · 44 across the 7 of their papers we have counts for
7 papers
Orbital angular momentum of scalar field generated by gravitational scatterings
Ryusuke Nishikawa, Ken-ichi Nakao, Atsuki Masuda +2
It has been expected that astronomical observations to detect the orbital angular momenta of electromagnetic waves may give us a new insight into astrophysics. Previous works point…
Systematic error due to isotropic inhomogeneities
Hiroyuki Negishi, Ken-ichi Nakao, Chul-Moon Yoo +1
Usually the effects of isotropic inhomogeneities are not seriously taken into account in the determination of the cosmological parameters because of Copernican principle whose stat…
Newtonian self-gravitating system in a relativistic huge void universe model
Ryusuke Nishikawa, Ken-ichi Nakao, Chul-Moon Yoo
We consider a test of the Copernican Principle through observations of the large-scale structures, and for this purpose we study the self-gravitating system in a relativistic huge…
Comparison of two approximation schemes for solving perturbations in a LTB cosmological model
Ryusuke Nishikawa, Ken-ichi Nakao, Chul-Moon Yoo
Recently, the present authors studied perturbations in the Lemaitre-Tolman-Bondi cosmological model by applying the second-order perturbation theory in the dust Friedmann-Lemaitre-…
Two-point correlation function of density perturbations in a large void universe
Ryusuke Nishikawa, Chul-Moon Yoo, Ken-ichi Nakao
We study the two-point correlation function of density perturbations in a spherically symmetric void universe model which does not employ the Copernican principle. First we solve p…
Evolution of density perturbations in large void universe
Ryusuke Nishikawa, Chul-Moon Yoo, Ken-ichi Nakao
We study the evolution of linear density perturbations in a large spherical void universe which accounts for the acceleration of the cosmic volume expansion without introducing dar…
Stability analysis of Squashed Kaluza-Klein Black Holes with Charge
Ryusuke Nishikawa, Masashi Kimura
We study gravitational and electromagnetic perturbation around the squashed Kaluza-Klein black holes with charge. Since the black hole spacetime focused on this paper have $SU(2) \…