89 citations · 188 across the 11 of their papers we have counts for
11 papers
Geometric deformations of symmetric spacetimes with a string cloud
Hiroshi Kozaki, Satsuki Matsuno, Tatsuhiko Koike +2
We establish a deformation framework for highly symmetric solutions to the Einstein equations. In this framework, four-dimensional metrics are constructed from three-dimensional η-…
Spacetime constructed from a contact manifold with a degenerate metric
Hiroshi Kozaki, Hideki Ishihara, Tatsuhiko Koike +1
We construct a four-dimensional spacetime using a three-dimensional contact manifold equipped with a degenerate metric. The degenerate metric is set to be compatible with the conta…
Nambu-Goto Strings with a null symmetry and contact structure
Hiroshi Kozaki, Tatsuhiko Koike, Yoshiyuki Morisawa +1
We study the classical dynamics of the Nambu-Goto strings with a null symmetry in curved spacetimes admitting a null Killing vector field. The Nambu-Goto equation is reduced to fir…
Membranes with a symmetry of cohomogeneity one
Hiroshi Kozaki, Tatsuhiko Koike, Hideki Ishihara
We study the dynamics of the Nambu-Goto membranes with cohomogeneity one symmetry, i.e., the membranes whose trajectories are foliated by homogeneous surfaces. It is shown that the…
Exactly solvable strings in Minkowski spacetime
Hiroshi Kozaki, Tatsuhiko Koike, Hideki Ishihara
We study the integrability of the equations of motion for the Nambu-Goto strings with a cohomogeneity-one symmetry in Minkowski spacetime. A cohomogeneity-one string has a world su…
Perturbations of Spacetime around a Stationary Rotating Cosmic String
Kouji Ogawa, Hideki Ishihara, Hiroshi Kozaki +1
We consider the metric perturbations around a stationary rotating Nambu-Goto string in Minkowski spacetime. By solving the linearized Einstein equations, we study the effects of az…