EXACT SOLUTIONS OF THE EINSTEIN–MAXWELL EQUATIONS IN CHARGED PERFECT FLUID SPHERES FOR THE GENERALIZED TOLMAN–OPPENHEIMER–VOLKOFF EQUATIONS

2013 ◽  
Vol 22 (02) ◽  
pp. 1350009 ◽  
Author(s):  
LI ZOU ◽  
FANG-YU LI ◽  
HAO WEN
Keyword(s):  
Cosmological Constant ◽  
Exact Solutions ◽  
Perfect Fluid ◽  
Maxwell Equations ◽  
Constant Density ◽  
New Exact Solutions ◽  
First Time ◽  
Classical Constant ◽  
Fluid Spheres ◽  
Charged Case

Exact solutions of the Einstein–Maxwell equations for spherically symmetric charged perfect fluid have been broadly studied so far. However, the cases with a nonzero cosmological constant are seldom focused. In the present paper, the Tolman–Oppenheimer–Volkoff (TOV) equations have been generalized from the neutral case of hydrostatic equilibrium to the charged case of hydroelectrostatic equilibrium, and base on it, for the first time we find a series of new exact solutions of Einstein–Maxwell's equations with a nonzero cosmological constant for static charged perfect fluid spheres. Moreover, two special TOV equations and two classical constant density interior solutions are also given.

scholarly journals STATIC CYLINDRICALLY SYMMETRIC INTERIOR SOLUTIONS IN f(R) GRAVITY

2012 ◽  
Vol 27 (25) ◽  
pp. 1250138 ◽  
Author(s):  
M. SHARIF ◽  
SADIA ARIF
Keyword(s):  
Energy Density ◽  
Exact Solutions ◽  
Perfect Fluid ◽  
Functional Form ◽  
Ricci Scalar ◽  
The Other ◽  
New Exact Solutions ◽  
Cylindrically Symmetric ◽  
Theory Of Gravity ◽  
Interior Solutions

We investigate some exact static cylindrically symmetric solutions for a perfect fluid in the metric f(R) theory of gravity. For this purpose, three different families of solutions are explored. We evaluate energy density, pressure, Ricci scalar and functional form of f(R). It is interesting to mention here that two new exact solutions are found from the last approach, one is in particular form and the other is in the general form. The general form gives a complete description of a cylindrical star in f(R) gravity.

scholarly journals New Exact Solutions for High Dispersive Cubic-Quintic Nonlinear Schrödinger Equation

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Yongan Xie ◽  
Shengqiang Tang
Keyword(s):  
Solitary Wave ◽  
Exact Solutions ◽  
Bifurcation Theory ◽  
Solitary Wave Solutions ◽  
Nonlinear Schrödinger ◽  
Light Pulses ◽  
New Exact Solutions ◽  
Wave Solutions ◽  
First Time ◽  
Quintic Nonlinear Schrödinger Equation

We study a class of high dispersive cubic-quintic nonlinear Schrödinger equations, which describes the propagation of femtosecond light pulses in a medium that exhibits a parabolic nonlinearity law. Applying bifurcation theory of dynamical systems and the Fan sub-equations method, more types of exact solutions, particularly solitary wave solutions, are obtained for the first time.

THE TOLMAN–OPPENHEIMER–VOLKOFF EQUATIONS AND THE SPACETIME PROPERTIES OF THE SCHWARZSCHILD–DE SITTER CONSTANT DENSITY INTERIOR SOLUTION

2014 ◽  
Vol 23 (02) ◽  
pp. 1450016 ◽  
Author(s):  
LI ZOU ◽  
FANG-YU LI ◽  
TAO LI
Keyword(s):  
Perfect Fluid ◽  
Hydrostatic Equilibrium ◽  
Einstein Equations ◽  
Interior Solution ◽  
Constant Density ◽  
De Sitter ◽  
Spatial Curvature ◽  
Static Solutions ◽  
Cosmological Constants ◽  
Fluid Spheres

In this paper, we first deduce the Tolman–Oppenheimer–Volkoff (TOV) equations and Schwarzschild–de Sitter (SdS) constant-density interior solutions of perfect fluid spheres in hydrostatic equilibrium by the Einstein equations with a nonzero cosmological constant. The TOV equations and the spacetime properties of exact solutions inside uniform perfect fluid spheres with different spatial curvature and cosmological constants will be respectively analyzed in detail. Moreover, a brief comparison between the internal static solutions of the SdS type and the dynamical Einstein–Strauss–de Sitter (ESdS) vacuole spacetime is obtained.

scholarly journals Perfect fluid spheres with cosmological constant

2008 ◽  
Vol 77 (6) ◽  
Author(s):  
Christian G. Böhmer ◽  
Gyula Fodor
Keyword(s):  
Cosmological Constant ◽  
Perfect Fluid ◽  
Fluid Spheres

ALGORITHMIC CONSTRUCTION OF EXACT SOLUTIONS FOR NEUTRAL STATIC PERFECT FLUID SPHERES

2013 ◽  
Vol 22 (09) ◽  
pp. 1350052 ◽  
Author(s):  
SUDAN HANSRAJ ◽  
DANIEL KRUPANANDAN
Keyword(s):  
Exact Solutions ◽  
Perfect Fluid ◽  
Complete Solution ◽  
Positive Definiteness ◽  
Energy Conditions ◽  
Einstein Field Equations ◽  
Field Equations ◽  
New Exact Solutions ◽  
Algorithmic Construction ◽  
Fluid Spacetimes

Although it ranks amongst the oldest of problems in classical general relativity, the challenge of finding new exact solutions for spherically symmetric perfect fluid spacetimes is still ongoing because of a paucity of solutions which exhibit the necessary qualitative features compatible with observational evidence. The problem amounts to solving a system of three partial differential equations in four variables, which means that any one of four geometric or dynamical quantities must be specified at the outset and the others should follow by integration. The condition of pressure isotropy yields a differential equation that may be interpreted as second-order in one of the space variables or also as first-order Ricatti type in the other space variable. This second option has been fruitful in allowing us to construct an algorithm to generate a complete solution to the Einstein field equations once a geometric variable is specified ab initio. We then demonstrate the construction of previously unreported solutions and examine these for physical plausibility as candidates to represent real matter. In particular we demand positive definiteness of pressure, density as well as a subluminal sound speed. Additionally, we require the existence of a hypersurface of vanishing pressure to identify a radius for the closed distribution of fluid. Finally, we examine the energy conditions. We exhibit models which display all of these elementary physical requirements.

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