SCALAR FIELDS RECONSTRUCTION OF VISCOUS GDE WITH VARYING G

2014 ◽  
Vol 23 (01) ◽  
pp. 1450002 ◽  
Author(s):  
MOSTAFA SHARIFIAN ◽  
AHMAD SHEYKHI
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Gravitational Constant ◽  
Scalar Fields ◽  
Frw Universe ◽  
Ghost Dark Energy ◽  
Scalar Field Models ◽  
Varying Gravitational Constant ◽  
The Universe

In this paper, we first study the effects of the varying gravitational constant G as well as the bulk viscosity on the evolution of the Universe field with pressureless dark matter and ghost dark energy (GDE). Then, we establish a correspondence between viscous GDE and scalar field models of dark energy including quintessence, tachyon, K-essence and dilaton energy density in a flat FRW universe. This correspondence allows us to reconstruct the potential and dynamics of the scalar fields according to the evolution of interacting viscous GDE with varying G.

scholarly journals QCD MODIFIED GHOST SCALAR FIELD DARK ENERGY MODELS

2013 ◽  
Vol 22 (05) ◽  
pp. 1350018 ◽  
Author(s):  
K. KARAMI ◽  
S. ASADZADEH ◽  
M. MOUSIVAND ◽  
Z. SAFARI
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Linear Perturbation ◽  
Density Parameter ◽  
Frw Cosmology ◽  
Frw Universe ◽  
Ghost Dark Energy ◽  
Energy Models ◽  
Scalar Field Models ◽  
Ghost Scalar Field

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.

scholarly journals Correspondence off(R,∇R)Modified Gravity with Scalar Field Models

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Abdul Jawad ◽  
Ujjal Debnath
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
State Parameter ◽  
Scalar Fields ◽  
Frw Universe ◽  
Tachyonic Field ◽  
Energy Models ◽  
The Stability ◽  
Scalar Potentials ◽  
The Universe

This paper is devoted to study the scalar field dark energy models by taking its different aspects in the framework off(R,∇R)gravity. We consider flat FRW universe to construct the equation of state parameter governed byf(R,∇R)gravity. The stability of the model is discussed with the help of squared speed of sound parameter. It is found that models show quintessence behavior of the universe in stable as well as unstable modes. We also develop the correspondence off(R,∇R)model with some scalar field dark energy models like quintessence, tachyonic field,k-essence, dilaton, hessence, and DBI-essence. The nature of scalar fields and corresponding scalar potentials is being analyzed inf(R,∇R)gravity graphically which show consistency with the present day observations about accelerated phenomenon.

Interacting new agegraphic version of pilgrim dark energy

2015 ◽  
Vol 24 (08) ◽  
pp. 1550061 ◽  
Author(s):  
Abdul Jawad ◽  
G. Abbas
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Kinetic Energy ◽  
Dilaton Field ◽  
Frw Universe ◽  
Eos Parameter ◽  
Pilgrim Dark Energy ◽  
Scalar Field Models ◽  
Age Of The Universe ◽  
The Universe

We discuss the cosmological evolution of the interacting pilgrim dark energy (DE) with conformal age of the universe in flat FRW universe. We evaluate the equation of state (EoS) parameter for three different values of interacting parameter which evolutes the universe from matter dominated to phantom-like eras by evolving quintessence as well as vacuum DE eras. We also give the correspondence of the present DE model with quintessence, tachyon, k-essence, dilaton and DBI-essence scalar field models. We discuss the dynamics of scalar field and corresponding potentials. We find that the behavior of scalar field, corresponding potentials and kinetic energy terms (in k-essence and dilaton field) consistent with the present day observations. Also, cosmological planes such as [Formula: see text] and r - s planes corresponds to ΛCDM limit.

scholarly journals FERMIONIC AND SCALAR FIELDS AS SOURCES OF INTERACTING DARK MATTER–DARK ENERGY

2011 ◽  
Vol 20 (13) ◽  
pp. 2543-2558 ◽  
Author(s):  
SAMUEL LEPE ◽  
JAVIER LORCA ◽  
FRANCISCO PEÑA ◽  
YERKO VÁSQUEZ
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Analytical Solution ◽  
Scalar Fields ◽  
Nonminimal Coupling ◽  
Field Equations ◽  
Fermionic Field ◽  
Minimal Coupling ◽  
Constant Type

From a variational action with nonminimal coupling with a scalar field and classical scalar and fermionic interaction, cosmological field equations can be obtained. Imposing a Friedmann–Lemaître–Robertson–Walker (FLRW) metric, the equations lead directly to a cosmological model consisting of two interacting fluids, where the scalar field fluid is interpreted as dark energy and the fermionic field fluid is interpreted as dark matter. Several cases were studied analytically and numerically. An important feature of the non-minimal coupling is that it allows crossing the barrier from a quintessence to phantom behavior. The insensitivity of the solutions to one of the parameters of the model permits it to find an almost analytical solution for the cosmological constant type of universe.

INTERACTING GENERALIZED DARK ENERGY AND RECONSTRUCTION OF SCALAR FIELD MODELS

2013 ◽  
Vol 28 (38) ◽  
pp. 1350180 ◽  
Author(s):  
M. SHARIF ◽  
ABDUL JAWAD
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Dark Energy Model ◽  
Cold Dark Matter ◽  
Scalar Potential ◽  
Scalar Fields ◽  
Phantom Divide ◽  
Evolution Parameter ◽  
Scalar Field Models ◽  
Phantom Divide Line

In this paper, we consider the interacting generalized dark energy with cold dark matter and analyze the behavior of evolution parameter via dark energy and interacting parameters. It is found that the evolution parameter crosses the phantom divide line in most of the cases of integration constants. We also establish the correspondence of scalar field models (quintessence, k-essence and dilaton) with this dark energy model in which scalar fields show the increasing behavior. The scalar potential corresponds to attractor solutions in quintessence case.

scholarly journals CAN BRANS–DICKE SCALAR FIELD ACCOUNT FOR DARK ENERGY AND DARK MATTER?

2006 ◽  
Vol 21 (15) ◽  
pp. 1241-1248 ◽  
Author(s):  
M. ARIK ◽  
M. C. ÇALIK
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Energy Density ◽  
Late Time ◽  
Energy Contribution ◽  
Time Solution ◽  
The Universe

By using a linearized non-vacuum late time solution in Brans–Dicke cosmology, we account for the 75% dark energy contribution but not for approximately 23% dark matter contribution to the present day energy density of the universe.

A look to nonlinear interacting Ghost dark energy cosmology

2016 ◽  
Vol 31 (24) ◽  
pp. 1650137
Author(s):  
Martiros Khurshudyan
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Dark Energy Model ◽  
Cold Dark Matter ◽  
Cosmological Parameters ◽  
Comprehensive Understanding ◽  
Ghost Dark Energy ◽  
Hierarchy Analysis ◽  
Hubble Horizon ◽  
The Universe

In this paper, we organize a look to nonlinear interacting Ghost dark energy cosmology involving a discussion on the thermodynamics of the Ghost dark energy, when the universe is bounded via the Hubble horizon. One of the ways to study a dark energy model, is to reconstruct thermodynamics of it. Ghost dark energy is one of the models of the dark energy which has an explicitly given energy density as a function of the Hubble parameter. There is an active discussion towards various cosmological scenarios, where the Ghost dark energy interacts with the pressureless cold dark matter (CDM). Recently, various models of the varying Ghost dark energy has been suggested, too. To have a comprehensive understanding of suggested models, we will discuss behavior of the cosmological parameters on parameter-redshift [Formula: see text] plane. Some discussion on Om and statefinder hierarchy analysis of these models is presented. Moreover, up to our knowledge, suggested forms of interaction between the Ghost dark energy and cold dark matter (CDM) are new, therefore, within obtained results, we provide new contribution to previously discussed models available in the literature. Our study demonstrates that the forms of the interactions considered in the Ghost dark energy cosmology are not exotic and the justification of this is due to the recent observational data.

scholarly journals CONSTRAINING TEVES GRAVITY AS EFFECTIVE DARK MATTER AND DARK ENERGY

2007 ◽  
Vol 16 (12a) ◽  
pp. 2055-2063 ◽  
Author(s):  
HONGSHENG ZHAO
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Gravitational Lensing ◽  
Cold Dark Matter ◽  
High Redshift ◽  
Elliptical Galaxies ◽  
Dual Roles ◽  
Acceleration Of The Universe ◽  
The Universe

The phenomena customarily described with the standard ΛCDM model are broadly reproduced by an extremely simple model in TeVeS, Bekenstein's1 modification of general relativity motivated by galaxy phenomenology. Our model can account for the acceleration of the Universe seen at SNeIa distances without a cosmological constant, and the accelerations seen in rotation curves of nearby spiral galaxies and gravitational lensing of high-redshift elliptical galaxies without cold dark matter. The model is consistent with BBN and the neutrino mass between 0.05 eV to 2 eV. The TeVeS scalar field is shown to play the effective dual roles of dark matter and dark energy, with the amplitudes of the effects controlled by a μ function of the scalar field, called the μ essence here. We also discuss outliers to the theory's predictions on multiimaged galaxy lenses and outliers on the subgalaxy scale.

scholarly journals Thermodynamical description of the ghost dark energy model

2015 ◽  
Vol 24 (07) ◽  
pp. 1550048 ◽  
Author(s):  
M. Honarvaryan ◽  
A. Sheykhi ◽  
H. Moradpour
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Dark Energy Model ◽  
State Parameter ◽  
Thermal Fluctuations ◽  
Mutual Interaction ◽  
Coincidence Problem ◽  
Ghost Dark Energy ◽  
Equation Of State Parameter ◽  
The Universe

In this paper, we point out thermodynamical description of ghost dark energy (GDE) and its generalization to the early universe. Thereinafter, we find expressions for the entropy changes of these dark energy (DE) candidates. In addition, considering thermal fluctuations, thermodynamics of the DE component interacting with a dark matter (DM) sector is addressed. We will also find the effects of considering the coincidence problem on the mutual interaction between the dark sectors, and thus the equation of state parameter of DE. Finally, we derive a relation between the mutual interaction of the dark components of the universe, accelerated with the either GDE or its generalization, and the thermodynamic fluctuations.

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