Zobrazeno 1 - 10
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pro vyhledávání: '"Siino, Masaru"'
Autor:
Siino, Masaru
To comprehend the shadow of a black hole in a general spacetime, we have investigated the concept of the maximal black room (MBR). The boundary of the MBR is a non-spacelike hypersurface that contains at least one null geodesic tangent to its boundar
Externí odkaz:
http://arxiv.org/abs/2305.08362
Autor:
Siino, Masaru
The role of the wandering null geodesic is studied in a black hole spacetime. Based on the continuity of the solution of the geodesic equation, the wandering null geodesics commonly exist and explain the typical phenomena of the optical observation o
Externí odkaz:
http://arxiv.org/abs/2107.06551
Autor:
Siino, Masaru
Causal concept for the general black hole shadow is investigated, instead of the photon sphere. We define several `wandering null geodesics' as complete null geodesics accompanied by repetitive conjugate points, which would correspond to null geodesi
Externí odkaz:
http://arxiv.org/abs/1908.02921
Autor:
Siino, Masaru
In (2+1)-dimensional pure gravity with cosmological constant, the dynamics of double torus universe with pinching parameter is investigated. Each mode of affine stretching deformation is illustrated in the context of horizontal foliation along the ho
Externí odkaz:
http://arxiv.org/abs/1709.06712
Autor:
Siino, Masaru
A homogeneous two-dimensional metric including the degrees of freedom of Teichm\"uller deformation is developed. The Teichm\"uller deformation is incorporated by affine stretching of complex structure. According to Yamada's investigation by pinching
Externí odkaz:
http://arxiv.org/abs/1509.02266
We investigate perturbations of a class of spherically symmetric solutions in massive gravity and bi-gravity. The background equations of motion for the particular class of solutions we are interested in reduce to a set of the Einstein equations with
Externí odkaz:
http://arxiv.org/abs/1509.02096
Autor:
Kurita, Yasunari, Siino, Masaru
Publikováno v:
Phys. Rev. D 89, 024018 (2014)
We investigate the Teichm\"{u}ller parameters for a Euclidean multiple BTZ black hole spacetime. To induce a complex structure in the asymptotic boundary of such a spacetime, we consider the limit in which two black holes are at a large distance from
Externí odkaz:
http://arxiv.org/abs/1310.5326
We find new, simple cosmological solutions with flat, open, and closed spatial geometries, contrary to the previous wisdom that only the open model is allowed. The metric and the St\"{u}ckelberg fields are given explicitly, showing nontrivial configu
Externí odkaz:
http://arxiv.org/abs/1205.4938
Publikováno v:
Prog.Theor.Phys.125:1053-1065,2011
We construct an exact solution for the spherical gravitational collapse in a single coordinate patch. To describe the dynamics of collapse, we use a generalized form of the Painlev\'e-Gullstrand coordinates in the Schwarzschild spacetime. The time co
Externí odkaz:
http://arxiv.org/abs/1008.0470
Publikováno v:
Phys.Rev.D81:083530,2010
We derive the slow-roll conditions for a non-minimally coupled scalar field (extended quintessence) during the radiation/matter dominated era extending our previous results for thawing quintessence. We find that the ratio $\ddot\phi/3H\dot\phi$ becom
Externí odkaz:
http://arxiv.org/abs/1002.2986