Dilatonic dyon black hole solutions in the model with two Abelian gauge fields

Dilatonic black hole dyon-like solutions in the gravitational 4d model with a scalar field, two 2-forms, two dilatonic coupling constants λi ≠ 0, i = 1,2, obeying λ1 ≠ − λ2 and sign parameter ε = ±1 for scalar field kinetic term are considered. Here ε = −1 corresponds to ghost scalar field. These solutions are defined up to solutions of two master equations for two moduli functions, when λi2 ≠ 1/2 for ε = −1. A set of bounds on gravitational mass and scalar charge are presented by using a certain conjecture on parameters of solutions, when 1 + 2λi2ε > 0, i = 1, 2.

QCD MODIFIED GHOST SCALAR FIELD DARK ENERGY MODELS

Within the framework of FRW cosmology, we study the QCD modified ghost scalar field models of dark energy (DE) in the presence of both interaction and viscosity. For a spatially nonflat FRW universe containing modified ghost dark energy (MGDE) and dark matter (DM), we obtain the equation of state of MGDE, the deceleration parameter as well as a differential equation governing the MGDE density parameter. We also investigate the growth of structure formation for our model in a linear perturbation regime. Furthermore, we reconstruct both the dynamics and potentials of the quintessence, tachyon, K-essence and dilaton scalar field DE models according to the evolution of the MGDE density.

SPATIALLY FLAT FRW MODELS WITH A NONMINIMALLY COUPLED GHOST SCALAR FIELD AND PERFECT FLUID IN EINSTEIN–CARTAN THEORY

Exact general solutions to the Einstein–Cartan equations are obtained for spatially flat Friedmann cosmologies with a nonminimally coupled ghost scalar field and perfect fluid. It is shown that both singular and bouncing models are possible. An analogous problem is investigated in general relativity. Some effects of torsion are elucidated. The role of perfect fluid in the Einstein–Cartan cosmology is discussed.