3 papers
gr-qc2026
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…
gr-qc2024
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…
gr-qc2024
Strings in five-dimensional anti-de Sitter space with a symmetry
Tatsuhiko Koike, Hiroshi Kozaki, Hideki Ishihara
The equation of motion of an extended object in spacetime reduces to an ordinary differential equation in the presence of symmetry. By properly defining of the symmetry with notion…