We present an exact analytical solution of the gravitational field equations describing a static spherically symmetric anisotropic quark matter distribution. The radial pressure inside the star is assumed to obey a li...We present an exact analytical solution of the gravitational field equations describing a static spherically symmetric anisotropic quark matter distribution. The radial pressure inside the star is assumed to obey a linear equation of state, while the tangential pressure is a complicated function of the radial coordinate. In order to obtain the general solution of the field equations a particular density profile inside the star is also assumed. The anisotropic pressure distribution leads to an increase in the maximum radius and mass of the quark star, which in the present model is around three solar masses.展开更多
This paper investigates static axially symmetric models in self-interacting Brans-Dicke gravity. We discuss physically feasible sources of models, derive field equations as well as evolution equations from Bianchi ide...This paper investigates static axially symmetric models in self-interacting Brans-Dicke gravity. We discuss physically feasible sources of models, derive field equations as well as evolution equations from Bianchi identities and construct structure scalars. Using these scalars and evolution equations, the inhomogeneity factors of the system are evaluated. It is found that structure scalars related to double dual of Riemann tensor control the density inhomogeneity. Finally, we obtain exact solutions of homogenous isotropic and inhomogeneous anisotropic spheroid models. It turns out that homogenous solutions reduce to Schwarzschild type interior solutions for a spherical case. We conclude that homogenous models involve homogenous distribution of scalar field whereas inhomogeneous correspond to inhomogeneous sca/ar field.展开更多
For the initial boundary value problem about a type of parabolicMonge Ampe re equation of the form (IBVP):{-D tu+( det D^(2)_(x)u) 1/n =f(x,t),(x,t)∈Q= Ω ×(0,T],u(x,t)=(x,t)(x,t)∈ pQ},where Ω is a ...For the initial boundary value problem about a type of parabolicMonge Ampe re equation of the form (IBVP):{-D tu+( det D^(2)_(x)u) 1/n =f(x,t),(x,t)∈Q= Ω ×(0,T],u(x,t)=(x,t)(x,t)∈ pQ},where Ω is a bounded convex domain in R n ,the result in by Ivochkina and Ladyzheskaya is improved in the sense that, under assumptions that the data of the problem possess lower regularity and satisfy lower order compatibility conditions than those in , the existence of classical solution to (IBVP) is still established (see Theorem 1.1 below). This can not be realized by only using the method in . The main additional effort the authors have done is a kind of nonlinear perturbation.展开更多
文摘We present an exact analytical solution of the gravitational field equations describing a static spherically symmetric anisotropic quark matter distribution. The radial pressure inside the star is assumed to obey a linear equation of state, while the tangential pressure is a complicated function of the radial coordinate. In order to obtain the general solution of the field equations a particular density profile inside the star is also assumed. The anisotropic pressure distribution leads to an increase in the maximum radius and mass of the quark star, which in the present model is around three solar masses.
文摘This paper investigates static axially symmetric models in self-interacting Brans-Dicke gravity. We discuss physically feasible sources of models, derive field equations as well as evolution equations from Bianchi identities and construct structure scalars. Using these scalars and evolution equations, the inhomogeneity factors of the system are evaluated. It is found that structure scalars related to double dual of Riemann tensor control the density inhomogeneity. Finally, we obtain exact solutions of homogenous isotropic and inhomogeneous anisotropic spheroid models. It turns out that homogenous solutions reduce to Schwarzschild type interior solutions for a spherical case. We conclude that homogenous models involve homogenous distribution of scalar field whereas inhomogeneous correspond to inhomogeneous sca/ar field.
文摘For the initial boundary value problem about a type of parabolicMonge Ampe re equation of the form (IBVP):{-D tu+( det D^(2)_(x)u) 1/n =f(x,t),(x,t)∈Q= Ω ×(0,T],u(x,t)=(x,t)(x,t)∈ pQ},where Ω is a bounded convex domain in R n ,the result in by Ivochkina and Ladyzheskaya is improved in the sense that, under assumptions that the data of the problem possess lower regularity and satisfy lower order compatibility conditions than those in , the existence of classical solution to (IBVP) is still established (see Theorem 1.1 below). This can not be realized by only using the method in . The main additional effort the authors have done is a kind of nonlinear perturbation.
