Anisotropic Bianchi-V dark energy model under the new perspective of accelerated expansion of the universe in Brans–Dicke theory of gravitation

A ghost dark energy model has been recently put forward to explain the current accelerated expansion of the universe. In this model, we develop the general scheme for modified f(R) gravity reconstruction from realistic anisotropic Bianchi type I cosmology. Power-law volumetric expansion is used to obtain exact solutions of the field equations. We discuss the physical behavior of the solutions and anisotropy behavior of the fluid, the expansion parameter, and the model in future evolution of the universe. We reconstruct corresponding f(R) gravities and obtain the equation of state parameter. We show that the corresponding f(R) gravity of the ghost dark energy model can behave like phantom or quintessence of the selected models that describe accelerated expansion of the universe.

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The influence of the dark energy model in the Roche potential for interacting galaxies

Izvestiya vysshikh uchebnykh zavedenii. Fizika ◽

10.17223/00213411/63/11/127 ◽

2020 ◽

pp. 127-130

Author(s):

U.N. Zakirov ◽

Keyword(s):

Dark Energy ◽

Equivalence Principle ◽

Dark Energy Model ◽

Energy Model ◽

Interacting Galaxies ◽

Vacuum Field ◽

Accelerated Expansion ◽

Expansion Of The Universe ◽

First Time ◽

The Universe

For the first time, the influence of the dark energy model - a new non-vacuum field - in the generalized (with allowance for the equivalence principle) Roche potential for interacting galaxies was considered. The equation of thermodynamics of the mentioned field and its possible evolutions affecting on the accelerated expansion of the Universe is given.

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Interacting new holographic dark energy model with varying G in nonflat universe

Canadian Journal of Physics ◽

10.1139/cjp-2012-0503 ◽

2013 ◽

Vol 91 (12) ◽

pp. 1090-1092

Author(s):

V. Fayaz ◽

F. Felegary ◽

H. Hossienkhani

Keyword(s):

Dark Matter ◽

Dark Energy ◽

Dark Energy Model ◽

Holographic Dark Energy ◽

Energy Model ◽

Accelerated Expansion ◽

Late Time ◽

Holographic Dark Energy Model ◽

Expansion Of The Universe ◽

The Universe

Motivated by the work of Karami and Fehri (Phys. Lett. B, 684, 61 (2010)). We generalize their work with varying G. We investigate the new holographic dark energy model with varying G. We consider a spatially nonflat universe containing interacting new holographic dark energy with pressureless dark matter. We obtain the equation of state and the deceleration parameters. Also we reconstruct ωA for a = a0tn and H = [β/(α − 1)](1/t) in the late time universe. We also obtain q for a = a0tn and H = [β/(α − 1)](1/t) in the present time universe, which describes accelerated expansion of the universe.

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Thermodynamics of the viscous f(T,B) gravity in the new agegraphic dark energy model

Modern Physics Letters A ◽

10.1142/s0217732320501667 ◽

2020 ◽

Vol 35 (20) ◽

pp. 2050166 ◽

Cited By ~ 4

Author(s):

A. Pourbagher ◽

Alireza Amani

Keyword(s):

Dark Energy ◽

Hubble Parameter ◽

Dark Energy Model ◽

Apparent Horizon ◽

Second Law Of Thermodynamics ◽

Energy Model ◽

Accelerated Expansion ◽

Agegraphic Dark Energy ◽

New Agegraphic Dark Energy ◽

The Universe

In this paper, we first obtain the energy density by the approach of the new agegraphic dark energy model, and then the [Formula: see text] gravity model is studied as an alternative to the dark energy in a viscous fluid by flat-FRW background, in which [Formula: see text] and [Formula: see text] are torsion scalar and boundary term. The Friedmann equations will be obtained in the framework of modified teleparallel gravity by tetrad components. We consider that the universe dominates with components such as matter and dark energy by an interacting model. The Hubble parameter is parameterized by the power-law for the scale factor, and then we fit the corresponding Hubble parameter with observational data constraints. The variation of the equation of state (EoS) for dark energy is plotted as a function of the redshift parameter, and the accelerated expansion of the universe is explored. In what follows, the stability of the model is also studied on the base of the sound speed parameter. Finally, the generalized second law of thermodynamics is investigated by entropies of inside and on the boundary of the apparent horizon in thermodynamics equilibrium.

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PRESENT ACCELERATION OF THE UNIVERSE, HOLOGRAPHIC ENERGY AND BRANS–DICKE THEORY

Modern Physics Letters A ◽

10.1142/s0217732309030205 ◽

2009 ◽

Vol 24 (22) ◽

pp. 1785-1792 ◽

Cited By ~ 24

Author(s):

B. NAYAK ◽

L. P. SINGH

Keyword(s):

Dark Energy ◽

Power Law ◽

Dark Energy Model ◽

Holographic Dark Energy ◽

Accelerated Expansion ◽

Temporal Behavior ◽

Holographic Dark Energy Model ◽

Acceleration Of The Universe ◽

Expansion Of The Universe ◽

The Universe

The present-day accelerated expansion of the universe is naturally addressed within the Brans–Dicke theory just by using holographic dark energy model with inverse of Hubble scale as IR cutoff and power law temporal behavior of scale factor. It is also concluded that if the universe continues to expand, then one day it might be completely filled with dark energy.

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Generalized interaction term inspired dark energy model in fractal universe

Modern Physics Letters A ◽

10.1142/s0217732320501266 ◽

2020 ◽

Vol 35 (15) ◽

pp. 2050126

Author(s):

Abdul Jawad ◽

Saba Qummer ◽

Shamaila Rani ◽

M. Younas

Keyword(s):

Dark Energy ◽

Dark Energy Model ◽

Cosmological Parameters ◽

State Parameter ◽

Energy Model ◽

Linear Term ◽

Accelerated Expansion ◽

Linear Interaction ◽

Interaction Term ◽

The Universe

By assuming generalized nonlinear and linear interaction term between dark matter and dark energy, we investigate the cosmic accelerated expansion of the universe. For this reason, we suppose a flat fractal universe platform as well as Tsallis holographic dark energy model. The Hubble horizon is being adopted as an infrared cutoff and extracted different cosmological parameters as well as plane. It is observed that equation-of-state parameter exhibits the quintom-like nature while ([Formula: see text]–[Formula: see text]) lies in thawing and freezing regions for different parametric values for both the cases. Furthermore, the squared sound speed shows stable behavior for nonlinear interaction term but shows the partially stable behavior for linear term. For both cases, the deceleration parameter leads to the accelerated phase of the universe and the consequences are comparable with observational data. The results for [Formula: see text]–[Formula: see text] plane, leads to the quintessence and phantom region of the universe for nonlinear case while this plane represents the Chaplygin gas behavior for linear term. The [Formula: see text] diagnostic also shows the satisfying results.

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RECONSTRUCTION OF NEW HOLOGRAPHIC SCALAR FIELD MODELS OF DARK ENERGY IN BRANS–DICKE UNIVERSE

Modern Physics Letters A ◽

10.1142/s0217732311034682 ◽

2011 ◽

Vol 26 (03) ◽

pp. 191-204 ◽

Cited By ~ 12

Author(s):

WEI-QIANG YANG ◽

YA-BO WU ◽

LI-MIN SONG ◽

YANG-YANG SU ◽

JIAN LI ◽

...

Keyword(s):

Dark Energy ◽

Scalar Field ◽

Dark Energy Model ◽

Holographic Dark Energy ◽

Chaplygin Gas ◽

Energy Model ◽

Accelerated Expansion ◽

Holographic Dark Energy Model ◽

Special Cases ◽

Expansion Of The Universe

Motivated by the work: K. Karami and J. Fehri, Phys. Lett. B684, 61 (2010) and A. Sheykhi, Phys. Lett. B681, 205 (2009), we generalize their work to the new holographic dark energy model with [Formula: see text] in the framework of Brans–Dicke cosmology. Concretely, we study the correspondence between the quintessence, tachyon, K-essence, dilaton scalar field and Chaplygin gas model with the new holographic dark energy model in the non-flat Brans–Dicke universe. Furthermore, we reconstruct the potentials and dynamics for these models. By analysis we can show that for new holographic quintessence and Chaplygin gas models, if the related parameters to the potentials satisfy some constraints, the accelerated expansion can be achieved in Brans–Dicke cosmology. In particular, the counterparts of fields and potentials in general relativity can describe accelerated expansion of the universe. It is worth stressing that not only can we give some new results in the framework of Brans–Dicke cosmology, but also the previous results of the new holographic dark energy in Einstein gravity can be included as special cases given by us.

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Dynamics of a quintom dark energy model non-minimally coupled with a mixed kinetic geometric term

Canadian Journal of Physics ◽

10.1139/cjp-2020-0037 ◽

2020 ◽

Author(s):

Mihai Marciu

Keyword(s):

Dark Energy ◽

Dark Energy Model ◽

Energy Model ◽

Accelerated Expansion ◽

Field Equations ◽

Distant Future ◽

Phantom Divide ◽

Phantom Divide Line ◽

Big Crunch ◽

The Universe

Within this work, a new dark energy model it is proposed, by taking into account a non-minimally mixed kinetic geometric coupling between the two fields which construct a quintom model. By considering numerical analysis of the corresponding field equations, the evolution of the Universe in the present model has been analyzed, taking into account different viable potentials. For exponential potentials, the model presents an accelerated expansion, and the dark energy equation of state exhibit the phantom divide line crossing. However, for a steeper potential, in the case of a mixed potential, it is observed that the Universe can manifest Big Crunch singularities in the distant future, and the moment for which the singularity occur is sensitive to the value of the mixed coupling strength embedded into the η coeffcient. The results show that an increase of the $\eta$ parameter determine a delay in the the Big Crunch time in the distant future. In the present context, the choice of the potential function play a fundamental role in the evolution of the dynamical system, leading to very distinct cosmological scenarios.

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A modified holographic Ricci dark energy model in a self-creation cosmology

Canadian Journal of Physics ◽

10.1139/cjp-2016-0486 ◽

2016 ◽

Vol 94 (12) ◽

pp. 1314-1318 ◽

Cited By ~ 4

Author(s):

M.P.V.V. Bhaskara Rao ◽

D.R.K. Reddy ◽

K. Sobhan Babu

Keyword(s):

Dark Energy ◽

Dark Energy Model ◽

Bianchi Type ◽

Energy Model ◽

Smooth Transition ◽

Type Ii ◽

Field Equations ◽

Ricci Dark Energy ◽

Theory Of Gravitation ◽

The Universe

This paper deals with a locally rotationally symmetric Bianchi type II space–time with dark matter and anisotropic modified holographic Ricci dark energy as source in second self-creation theory of gravitation proposed by Barber (Gen. Relativ. Gravit. 14, 117 (1982)). To solve the field equations of this theory we have used (i) hybrid expansion law, (ii) a relation between metric potentials and a modified holographic Ricci dark energy given by Chen and Jing (Phys. Lett. B, 679, 144 (2009)). The solution obtained represents a Bianchi type II modified holographic dark energy model in self-creation cosmology. We observe that there is a smooth transition of the universe from decelerated phase to accelerated phase. This fact is in good agreement with the observations of modern cosmology. We have also discussed some important physical aspects of the model.

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Cosmological constant

10.1093/oso/9780198802877.003.0026 ◽

2018 ◽

Author(s):

Michael Kachelriess

Keyword(s):

Dark Energy ◽

Cosmological Constant ◽

Accelerated Expansion ◽

Vacuum Fluctuations ◽

Present Epoch ◽

Modify Gravity ◽

Expansion Of The Universe ◽

The Universe

The contribution of vacuum fluctuations to the cosmological constant is reconsidered studying the dependence on the used regularisation scheme. Then alternative explanations for the observed accelerated expansion of the universe in the present epoch are introduced which either modify gravity or add a new component of matter, dubbed dark energy. The chapter closes with some comments on attempts to quantise gravity.

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