The general static spherical perfect fluid solution with EoS parameter w=-1/5
İbrahim Semiz
备注：
Added tables and conformal diagrams. Close to published version, which contains improved versions of some Penrose diagrams and an appendix on the Buchdahl transformation
The general analytical solution for the static spherically symmetric metric supported by a perfect fluid with isothermal (proportional) equation-of-state $p = w ρ$ is not known at the time of this writing, except for the trivial cases $w=0$ and $w=-1$; and for $w=-1/3$. We show that if Buchdahl coordinates are used, the problem becomes analytically solvable for $w=-1/5$; display and discuss the solution(s), and exhibit the connection of this case to the $w=-1$ case.
The gravitational collapse of a barotropic perfect fluid having the Equation of State (EoS) $p=kρ$, where $k$ is constant, is studied here in the framework of general relativity. We examine the restrictions on the Misner-Sharp mass function, because of the introduction of such an EoS, in terms of the compatibility of a certain pair of quasi-linear partial differential equations, obtained from Einstein's field equations. We find that except when this system of PDEs reduces to ODEs because of additional symmetries imposed on the spacetimes, or when they become compatible with each other in some …
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In this paper, we consider the Universe at the late stage of its evolution and deep inside the cell of uniformity. At these scales, the Universe is filled with inhomogeneously distributed discrete structures (galaxies, groups and clusters of galaxies). Supposing that the Universe contains also the cosmological constant and a perfect fluid with a negative constant equation of state (EoS) parameter $ω$ (e.g., quintessence, phantom or frustrated network of topological defects), we investigate scalar perturbations of the FRW metrics due to inhomogeneities. Our analysis shows that, to be compatible…
The present work investigates the gravitational collapse of a perfect fluid in $f(R)$ gravity models. For a general $f(R)$ theory, it is shown analytically that a collapse is quite possible. The singularity formed as a result of the collapse is found to be a curvature singularity of shell focusing type. The possibility of the formation of an apparent horizon hiding the central singularity depends on the initial conditions.
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Gravitational Collapse of Perfect Fluid in N-Dimensional Spherically Symmetric Spacetimes
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Thermodynamic acceptability of spherically symmetric perfect-fluid solutions in general relativity
Al-Farabi Kazakh National University（阿拉伯·法拉比哈萨克国立大学）；Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México（墨西哥国立自治大学核科学研究所）；Dipartimento di Fisica and ICRA, Università di Roma “La Sapienza”（罗马第一大学物理系及ICRA）
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