3 research outputs found
Spherical symmetry in -gravity
Spherical symmetry in gravity is discussed in details considering also
the relations with the weak field limit. Exact solutions are obtained for
constant Ricci curvature scalar and for Ricci scalar depending on the radial
coordinate. In particular, we discuss how to obtain results which can be
consistently compared with General Relativity giving the well known
post-Newtonian and post-Minkowskian limits. Furthermore, we implement a
perturbation approach to obtain solutions up to the first order starting from
spherically symmetric backgrounds. Exact solutions are given for several
classes of theories in both constant and .Comment: 13 page
Black hole solutions in F(R) gravity with conformal anomaly
In this paper, we consider theory instead of Einstein gravity
with conformal anomaly and look for its analytical solutions. Depending on the
free parameters, one may obtain both uncharged and charged solutions for some
classes of models. Calculation of Kretschmann scalar shows that there is
a singularity located at , which the geometry of uncharged (charged)
solution is corresponding to the Schwarzschild (Reissner-Nordstr\"om)
singularity. Further, we discuss the viability of our models in details. We
show that these models can be stable depending on their parameters and in
different epoches of the universe.Comment: 12 pages, one figur
Some exact solutions of F(R) gravity with charged (a)dS black hole interpretation
In this paper we obtain topological static solutions of some kind of pure
gravity. The present solutions are two kind: first type is uncharged
solution which corresponds with the topological (a)dS Schwarzschild solution
and second type has electric charge and is equivalent to the
Einstein--conformally invariant Maxwell solution. In other word,
starting from pure gravity leads to (charged) Einstein- solutions
which we interpreted them as (charged) (a)dS black hole solutions of pure
gravity. Calculating the Ricci and Kreschmann scalars show that there is
a curvature singularity at . We should note that the Kreschmann scalar of
charged solutions goes to infinity as , but with a rate slower
than that of uncharged solutions.Comment: 21 pages, 4 figures, generalization to higher dimensions, references
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