The dynamical stability of the static real scalar field solutions to the Einstein-Klein-Gordon equations revisited

On the Stability of Real Scalar Boson Stars

The recent developments in particle physics and cosmology suggest that scalar fields may have played an important role in the evolution of the early universe, for instance in primordial phase transitions, and that they may make up part of the dark matter. These facts motivated the study of gravitational equilibrium configurations of scalar fields, in particular for massive complex fields, which...

Analytical solutions for the fractional Klein-Gordon equation

In this paper, we solve a inhomogeneous fractional Klein-Gordon equation by the method of separating variables. We apply the method for three boundary conditions, contain Dirichlet, Neumann, and Robin boundary conditions, and solve some examples to illustrate the effectiveness of the method.

WAVELET SOLUTIONS OF THE KLEIN-GORDON EQUATION

Applications of He’s Variational Principle method and the Kudryashov method to nonlinear time-fractional differential equations

  In this paper, we establish exact solutions for the time-fractional Klein-Gordon equation, and the time-fractional Hirota-Satsuma coupled KdV system. The He’s semi-inverse and the Kudryashov methods are used to construct exact solutions of these equations. We apply He’s semi-inverse method to establish a variational theory for the time-fractional Klein-Gordon equation, and the time-fractiona...

دسته‌ای از جوابهای دقیق گرانش با مشتقات بالاتر در چهار بعد

 In this paper we consider the action of higher derivative gravity up to the second order terms in the scalars made from the Ricci scalar, Ricci and Riemann tensors. We use the Bach- Lanczos identity of the Weyl tensor in four dimensions and show that the solutions of 4-dimensional Einstein equations with cosmological constant term in vacuum, which are known as Einstein metrics, satisfy the fie...