相关论文: Oscillating phantom in $F(R)$ gravity
In this article, we attempt to describe cosmic late-time acceleration of the universe in the framework of $f(R,L_m)$ gravity by using an effective equation of state when the account is taken of bulk viscosity. We presume a non-linear…
We discuss the phenomenon of the smooth dynamical gravity induced crossing of the phantom divide line in a framework of simple cosmological models where it appears to occur rather naturally, provided the potential of the unique scalar field…
The present work deals with cosmological solutions in $f(R,T)$ gravity theory for perfect fluid with constant equation of state ($\omega$). For a viable cosmological solution $\omega$ is restricted to $\omega<\dfrac{1}{3}$. Also depending…
In this work we consider a cosmological scenario in which the Universe contracts initially having a bouncing-like behavior, and accordingly after it bounces off, it decelerates following a matter dominated like evolution and at very large…
It has recently been shown that $f(T)$ gravity has $\frac{n(n-3)}{2}+1$ physical degrees of freedom (d.o.f.) in $n$ dimensions, contrary to previous claims. The simplest physical interpretation of this fact is that the theory possesses a…
Many astrophysical data show that the expansion of our universe is accelerating. In this paper, we study the model of phantom with O(N) symmetry in background of loop quantum cosmology(LQC). We investigate the phase-space stability of the…
The cosmic acceleration is one of the most significant cosmological discoveries over the last century. Following the more accurate data a more dramatic result appears: the recent analysis of the observation data (especially from SNe Ia)…
We perform a dynamical system analysis of Myrzakulov or F(R, T) gravity, which is a subclass of affinely connected metric theories, where ones uses a specific but non-special connection, which allows for non-zero curvature and torsion…
An approach to evaluation of the smooth Feynman path integrals is developed for the study of quantum fluctuations of particles and fields in Euclidean time-space. The paths are described by sum of Gauss functions and are weighted with…
In this paper, we try to consider the stability conditions of a modified gravity coupled by Weyl tensor. In this way, we indicate the suitable conditions for a successful bounce while the equation of state (EoS) parameter crosses the…
For cosmologically interesting $f(R)$ gravity models, we derive the complete set of the linearized field equations in the Newtonian gauge, under environments of the solar system, galaxies and clusters respectively. Based on these equations,…
We propose an effective harmonic oscillator model in order to treat the fluctuations of the gravitational, strong and weak nuclear fields. With respect to the gravitational field, first we use the model to estimate its fluctuating strength,…
In this paper, we investigate and analyze the cosmological dynamics of the universe, with an effect of modified $f(R)$ gravity emerging at cosmological scale. We choose the Einstein frame as a physical frame. We consider phase portraits of…
We study a massive inflaton minimally coupled to the FRW Universe using the semiclassical gravity derived from canonical quantum gravity. It is found that the semiclassical quantum gravity leads to the power-law expansion $t^{2/3}$ in an…
Fluids in external gravity may oscillate with frequencies characteristic of the epicyclic motions of test particles. We explicitly demonstrate that global oscillations of a slender, perfect fluid torus around a Kerr black hole admit…
A Lagrangian derivation of the Equation of Motion (EOM) for static spherically symmetric metrics in F(R) modified gravity is presented. For a large class of metrics, our approach permits to reduce the EOM to a single equation and we show…
Gravity's quantum nature can be probed in a laboratory by witnessing the entanglement between the two quantum systems, which cannot be possible if gravity is a classical entity. In this paper, we will provide a simple example where we can…
The paper deals with a dynamical system analysis related to phantom cosmological model . Here gravity is coupled to phantom scalar field having scalar coupling function and a potential. The field equations are reduced to an autonomous…
We consider certain aspects of cosmological dynamics of a spatially curved Universe in $f(T)$ gravity. Local analysis allows us to find conditions for bounces and for static solutions; these conditions appear to be in general less…
We consider models of accelerating Universe elaborated for Finsler like gravity theories constructed on tangent bundles to Lorentz manifolds. In the osculating approximation, certain locally anisotropic configurations are similar to those…