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

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.

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

2009 ◽  
Vol 24 (22) ◽  
pp. 1785-1792 ◽  
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.

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

2011 ◽  
Vol 26 (03) ◽  
pp. 191-204 ◽  
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.

scholarly journals Observational constraints on interacting Tsallis holographic dark energy model

2019 ◽  
Vol 79 (9) ◽  
Author(s):  
Ehsan Sadri
Keyword(s):  
Dark Energy ◽  
Observational Data ◽  
Dark Energy Model ◽  
Large Scale ◽  
Gamma Ray ◽  
Holographic Dark Energy ◽  
Energy Model ◽  
Late Time ◽  
Acoustic Oscillations ◽  
Holographic Dark Energy Model

Abstract In this paper, we investigate a recent proposed model – so called the Tsallis holographic dark energy (THDE) model with consideration of the Hubble and the event future horizon as IR cutoffs. In this case, we consider the non-gravitational and phenomenological interaction between dark sectors. We fit the free parameters of the model using Pantheon Supernovae Type Ia data, Baryon Acoustic Oscillations, Cosmic Microwave Background, Gamma-Ray burst and the the local value of the Hubble constant. We examine the THDE model to check its compatibility with observational data using objective Information Criterion (IC). We find that the THDE models cannot be supported by observational data once the $$\Lambda $$ΛCDM is considered as the referring model. Therefore we re-examine the analysis with the standard holographic dark energy model (HDE) as another reference. Changing the $$\Lambda $$ΛCDM to main standard dark energy model (HDE), we observe the compatibility of the THDE models. Using the Alcock–Paczynski (AP) test we check the deviation of the model compared to $$\Lambda $$ΛCDM and HDE. Surveying the evolution of squared of sound speed $$v^2_s$$vs2 as an another test we check the stability of the interacting and non-interacting THDE models and we find that while the THDE model with the Hubble horizon as IR cutoff is unstable against the background perturbation, the future event horizon as IR cutoff show stability at the late time. In addition, using the modified version of the CAMB package, we observe the suppressing the CMB spectrum at small K-modes and large scale.

Reconstructing Tsallis holographic quintessence

2021 ◽  
Author(s):  
Umesh Kumar Sharma ◽  
Vandna Srivastava
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Quantum Gravity ◽  
Dark Energy Model ◽  
Holographic Dark Energy ◽  
Energy Model ◽  
Holographic Dark Energy Model ◽  
The Universe ◽  
Modified Entropy

Within the framework of quantum gravity and modified entropy-area formalism, the Tsallis holographic dark energy is an effort to peep into a mysterious content of the Universe, the dark energy, to analyze its nature. The Tsallis parameter [Formula: see text] provides the main characteristic of the Tsallis holographic dark energy. Opting the value of Tsallis parameter [Formula: see text], a quintessence scalar field description of the Tsallis holographic dark energy model can be obtained. In this work, we present this quintessential explanation of the Tsallis holographic dark energy with [Formula: see text] and reconstruct the dynamics of the scalar field and the potential of quintessence.

scholarly journals Unified Description of Dark Energy and Dark Matter within the Generalized Hybrid Metric-Palatini Theory of Gravity

Universe ◽  
2020 ◽  
Vol 6 (6) ◽  
pp. 78 ◽  
Author(s):  
Paulo M. Sá
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Fields ◽  
Accelerated Expansion ◽  
Late Time ◽  
Intermediate Phases ◽  
Expansion Of The Universe ◽  
Theory Of Gravity ◽  
The Universe ◽  
Unified Description

The generalized hybrid metric-Palatini theory of gravity admits a scalar-tensor representation in terms of two interacting scalar fields. We show that, upon an appropriate choice of the interaction potential, one of the scalar fields behaves like dark energy, inducing a late-time accelerated expansion of the universe, while the other scalar field behaves like pressureless dark matter that, together with ordinary baryonic matter, dominates the intermediate phases of cosmic evolution. This unified description of dark energy and dark matter gives rise to viable cosmological solutions, which reproduce the main features of the evolution of the universe.

Ghost dark energy models in Bianchi I cosmologies with modified gravity

2014 ◽  
Vol 92 (2) ◽  
pp. 168-172 ◽  
Author(s):  
V. Fayaz ◽  
H. Hossienkhani ◽  
A. Aghamohammadi ◽  
M. Amirabadi
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
General Scheme ◽  
Energy Model ◽  
Accelerated Expansion ◽  
Type I ◽  
Field Equations ◽  
Ghost Dark Energy ◽  
Expansion Of The Universe ◽  
The Universe

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.

scholarly journals DARK ENERGY AND THE FUTURE FATE OF THE UNIVERSE

2007 ◽  
Vol 22 (35) ◽  
pp. 2689-2699
Author(s):  
YUNGUI GONG ◽  
YUAN-ZHONG ZHANG
Keyword(s):  
Dark Energy ◽  
Event Horizon ◽  
Dark Energy Model ◽  
Holographic Dark Energy ◽  
Scale Factor ◽  
Energy Model ◽  
Holographic Dark Energy Model ◽  
Hubble Horizon ◽  
Size Criterion ◽  
The Universe

We consider the possibility of observing the onset of the late time inflation of our patch of the Universe. The Hubble size criterion and the event horizon criterion are applied to several dark energy models to discuss the problem of future inflation of the Universe. We find that the acceleration has not lasted long enough to confirm the onset of inflation by present observations for the dark energy model with constant equation of state, the holographic dark energy model and the generalized Chaplygin gas (GCG) model. For the flat ΛCDM model with Ωm0 = 0.3, we find that if we use the Hubble size criterion, we need to wait until the av which is the scale factor at the time when the onset of inflation is observed reaches 3.59 times of the scale factor aT when the Universe started acceleration, and we need to wait until av = 2.3aT to see the onset of inflation if we use the event horizon criterion. For the flat holographic dark energy model with d = 1, we find that av = 3.46aT with the Hubble horizon and av = 2.34aT with the event horizon, respectively. For the flat GCG model with the best supernova fitting parameter α = 1.2, we find that av = 5.50aT with the Hubble horizon and av = 2.08aT with the event horizon, respectively.

scholarly journals An interacting new holographic dark energy model: Observational constraints

2019 ◽  
Vol 28 (12) ◽  
pp. 1950152 ◽  
Author(s):  
Ehsan Sadri ◽  
Martiros Khurshudyan
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Observational Data ◽  
Dark Energy Model ◽  
Holographic Dark Energy ◽  
Current Model ◽  
Energy Model ◽  
Late Time ◽  
Holographic Dark Energy Model ◽  
Frw Universe

In this paper, we study an interacting new holographic dark energy model (NHDE) in DGP braneworld with a spatially flat FRW universe. Mainly, in this study we concentrate our attention on both interacting and noninteracting forms of the model. The study shows that the equation of state and the deceleration parameter depict an accelerated universe for all variety of interactions. On the other hand, the StateFinder analysis shows that the interacting and noninteracting behave similar to both quintessence and phantom dark energy and for the present value obey the behavior of quintessence. Moreover, the result of [Formula: see text]-diagnostic emphasizes on the result of the equation of state showing that the current model in high–[Formula: see text] stays in the quintessence era and in the late time has the Phantom-like behavior. By the use of the squared sound speed [Formula: see text] we find that the present mode has a good stability. In order to obtain the best fit values of the parameters in this work, we used the latest observational data (Pantheon, Boss DR12 and Planck 2015) implementing MCMC method by the use of EMCEE python package. We also employ AkaikeInformation Criterion (AIC) and Bayesian Information Criterion (BIC) model selection tools and comparethe model with both [Formula: see text]CDM and holographic Ricci dark energy as the reference models. We observe that the evidence against the interacting and noninteracting NHDE with consideration of both references is strongly positive and BIC rules out the NHDE model. Generally, the results of AIC and BIC state that the observational data do not favor the NHDE model.

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

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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