相关论文: Oscillating phantom in $F(R)$ gravity
Past analyses of the equation of state (EoS) of the Dark Energy (DE) were not incompatible with a phantom phase near our time. This has been the case in the years of WMAP observations, in combination with the remaining cosmological…
We study cosmological solutions in $R + \beta R^{N}$-gravity for an isotropic Universe filled with ordinary matter with the equation of state parameter $\gamma$. Using the Bogolyubov-Krylov-Mitropol'skii averaging method we find asymptotic…
The aim of this paper is to show, that the 'oscillating universe' is a viable alternative to inflation. We remind that this model provides a natural solution to the flatness or entropy and to the horizon problem of standard cosmology. We…
This article explores the cosmological scenario of the universe in the context of the $f(T)$ power law model, where $T$ represent the torsion scalar. To obtain the deterministic solution of the field equations we parametrized the effective…
We consider a four-dimensional flat-space Friedman universe, which is filled with two interacting ideal fluids (the coupling of dark energy with dark matter of special form). The gravitational equations of motion are solved. It is shown…
It is shown that F(R)-modified gravitational theories lead to curvature oscillations in astrophysical systems with rising energy density. The frequency and the amplitude of such oscillations could be very high and would lead to noticeable…
The reconstruction of f(R)-gravity is showed by using an auxiliary scalar field in the context of cosmological evolution, this development provide a way of reconstruct the form of the function f (R) for a given evolution of the Hubble…
In this paper we suggest an approach to analyse the motion of a test particle in the spacetime of a global monopole within a $f(R)$-like modified gravity. The field equations are written in a more simplified form in terms of…
This paper is devoted to examining cosmological bouncing scenarios in the framework of the recently proposed symmetric teleparallel gravity (or $f(Q)$ gravity), where the non-metricity scalar $Q$ represents the gravitational interaction. We…
We study the anisotropic Big Bang cosmology for a general non-linear equation of state (EoS) in standard general relativity cosmology in early times. According to brane world cosmology and loop quantum gravity which introduce a quadratic…
The experimental evidence that the equation of state (EOS) of the dark energy (DE) could be evolving with time/redshift (including the possibility that it might behave phantom-like near our time) suggests that there might be dynamical DE…
A bouncing scenario of a flat homogeneous and isotropic universe is explored by using the reconstruction technique for the power-law parametrization of the Hubble parameter in a modified gravity theory with higher-order curvature and trace…
Gravitational collapse of a spherically symmetric homogeneous perfect barotropic fluid with linear as well as polytropic type Equation of State (EoS) has been investigated in the framework of a linear model of $f(R,T)$ gravity. This…
In this article, the bulk viscosity is introduced in a modified gravity model. The gravitational action has a general $f(R,T)$ form, where $R$ and $ T $ are the curvature scalar and the trace of energy momentum tensor respectively. An…
In this paper, we investigate the cosmic expansion scenarios within the framework of $f(Q,T)$ gravity by using the affine equation of state (EoS) parameter. Specifically, we consider the linear form $f(Q,T)=Q+\beta T$, where $\beta$ is a…
We investigate alternative candidates to dark energy that can explain the current state of the universe in the framework of the generalized teleparallel theory of gravity $f(T)$ where $T$ denotes the torsion scalar. To achieve this, we…
We investigate possible realization of the phantom-like behavior in the framework of $f(R)$-gravity models where there are no phantom fields in the matter sector of the theory. By adopting some observationally reliable ansatz for $f(R)$, we…
The bouncing universe provides a possible solution to the Big Bang singularity problem. In this paper we study the bouncing solution in the universe dominated by the Quintom matter with an equation of state (EoS) crossing the cosmological…
In this paper, we have considered a quadratic variation of the deceleration parameter ($q$) as a function of cosmic time ($t$) which describes a smooth transition from the decelerating phase of the Universe to an accelerating one and also…
The modified gravity with 1/R term (R being scalar curvature) and the Einstein-Hilbert term is studied by incorporating the phantom scalar field. A number of cosmological solutions are derived in the presence of the phantom field in the…