Conserved Quantities in f(R) Gravity via Noether Symmetry

We investigate f(R)gravity using the Noether symmetry approach.For this purpose,we consider Friedmann Robertson–Walker(FRW)universe and spherically symmetric spacetimes.The Noether symmetry generators are evaluated for some specific choice of f(R)models in the presence of the gauge term.Further,we calculate the corresponding conserved quantities in each case.Moreover,the importance and stability criteria of these models are discussed.

f(G,T) Gravity with Cylindrically Symmetric Relativistic Fluids

The aim of this paper is to examine the structure scalars with account of f(G, T) theory of gravity. We consider the cylindrically symmetric spacetime with dissipative anisotropic background. We have determined the structure scalars by orthogonally decomposing the Riemann curvature tensor and it is shown that these scalars are associated with fundamental properties of fluid. We further investigate the mass function along with the transport equation and discuss their role on the evolutionary stages of relativistic stellar systems. We have also analyzed these structure scalars for static fluid distributions and it is concluded that all possible solutions of field equations can be expressed through these scalars.

Behavior of Anisotropic Compact Stars in f(R,∅) Gravity

The aim of this paper is to investigate modified f(R, ?) theory of gravity, where R and ? represent the Ricci scalar and scalar potential respectively. Specifically, we take the spherically symmetric spacetime to discuss the possible emergence of compact stars. We study the physical behavior of compact stars by considering 4 U 1820-30, SAX J1808-3658 and Her X1, which are three popular models of compact stars. The graphical analysis of energy density, radial pressure, tangential pressure, energy conditions as well as stability of compact stars has been shown. It is concluded that behavior of these three stars is usual for f(R, ?) gravity models with some specific choices of model parameters.

Plane Symmetric Solutions in f(R,T) Gravity

The main purpose of this paper is to investigate the exact solutions of plane symmetric spacetime in the context of f(R,T)gravity[Phys.Rev.D 84(2011)024020],where f(R,T)is an arbitrary function of Ricci scalar R and trace of the energy momentum tensor T.We explore the exact solutions for two different classes of f(R,T)models.The first class f(R,T)=R+2f(T)yields a solution which corresponds to Taub's metric while the second class f(R,T)=f_1(R)+f_2(T)provides two additional solutions which include the well known anti-deSitter spacetime.The energy densities and corresponding functions for f(R,T)models are evaluated in each case.

Energy Bounds for Static Spherically Symmetric Spacetime in f(R, G) Gravity

The main purpose of this paper is to investigate energy bounds in the context of f(R, G) gravity. To meet this aim, we choose static spherically symmetric spacetime in f(R, G) gravity to develop the field equations. We select three different models of f(R, G) gravity, which are thoroughly discussed in the literature. Firstly, the inequalities are formulated using energy bounds and then viability of the considered models are checked respectively. Graphical analysis show that specific f(R, G) gravity models are satisfied under suitable values of model parameters. It is shown that in a certain case energy bounds are satisfied expect SEC, which supports the late time acceleration expansion of unverse.