COSMOLOGICAL DYNAMICS OF DILATONIC (PHANTOM) DARK ENERGY MODEL

2006 ◽  
Vol 15 (09) ◽  
pp. 1501-1514 ◽  
Author(s):  
Z. G. HUANG ◽  
H. Q. LU
Keyword(s):  
Dark Energy ◽  
Kinetic Energy ◽  
Dark Energy Model ◽  
Energy Model ◽  
Density Parameter ◽  
Late Time ◽  
Sufficient Condition ◽  
Phantom Model ◽  
Attractor Solution ◽  
Phantom Dark Energy

In this paper, we study the cosmological dynamics of dilatonic dark energy model and its phantom model — with negative kinetic energy. When the potential is taken as the form [Formula: see text], we investigate the existence of a late time attractor solution, and find out the sufficient condition. One interesting feature found by us is that the evolutions of components of comic density are locally fluctuating on the way to the late time attractor. But this local fluctuation cannot hold the trend that the equation of state ω evolves to -1 and the cosmic density parameter Ωσ evolves to 1, which are important features for a dark energy model that can meet the current observations.

ATTRACTOR BEHAVIOR IN DILATONIC (PHANTOM) DARK ENERGY MODEL WITH POTENTIAL [1+(σ-A)2]e-Bσ

2006 ◽  
Vol 21 (39) ◽  
pp. 2977-2987
Author(s):  
Z. G. HUANG ◽  
H. Q. LU ◽  
W. FANG
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
Energy Model ◽  
Fine Tuning ◽  
Density Parameter ◽  
Dilaton Field ◽  
Phantom Model ◽  
Attractor Solution ◽  
Phantom Dark Energy ◽  
M Theory

In this paper, we consider the dilatonic dark energy model and its phantom model. Based on the dilatonic (phantom) model, we take the potential of dilaton field of the form [1+(σ-A)2]e-Bσ which seems to connect with ideas from M-theory, and analyze the sufficient condition for the existence of attractor solution. We find that the behavior of the attractor is not sensitive to the initial condition, thus the fine-tuning problem is alleviated. By numerical analysis, we investigate the asymptotic behavior of the attractor, which corresponds to an equation of state ω = -1 and a cosmic density parameter Ωσ = 1.

Exact solution of phantom dark energy model

2010 ◽  
Vol 19 (11) ◽  
pp. 119801 ◽  
Author(s):  
Wen-Fu Wang ◽  
Zheng-Wei Shui ◽  
Bin Tang
Keyword(s):  
Exact Solution ◽  
Dark Energy ◽  
Dark Energy Model ◽  
Energy Model ◽  
Phantom Dark Energy

scholarly journals Parametrization of Born-Infeld type phantom dark energy model

2009 ◽  
Vol 324 (1) ◽  
pp. 55-59
Author(s):  
Z. G. Huang ◽  
H. Q. Lu ◽  
W. Fang
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
Energy Model ◽  
Phantom Dark Energy

scholarly journals LATE-TIME PHANTOM UNIVERSE IN SO(1, 1) DARK ENERGY MODEL WITH EXPONENTIAL POTENTIAL

2005 ◽  
Vol 20 (15) ◽  
pp. 1147-1154 ◽  
Author(s):  
YI-HUAN WEI
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
Energy Model ◽  
Late Time ◽  
De Sitter ◽  
Exponential Potential ◽  
Coupling Energy ◽  
Expansion Phase ◽  
Perturbation Field ◽  
The Universe

We discuss the late-time property of universe and phantom field in the SO(1, 1) dark energy model for the potential V = V0e-βΦα with α and β two positive constants. We assume in advance some conditions satisfied by the late-time field to simplify equations, which are confirmed to be correct from the eventual results. For α < 2, the field falls exponentially off and the phantom equation of state rapidly approaches -1. When α = 2, the kinetic energy ρk and the coupling energy ρc become comparable but there is always ρk < -ρc so that the phantom property of field proceeds to hold. The analysis on the perturbation to the late-time field Φ illustrates the square effective mass of the perturbation field is always positive and thus the phantom is stable. The universe considered currently may evade the future sudden singularity and will evolve to de Sitter expansion phase.

scholarly journals FLRW cosmology of induced dark energy model and open universe

2017 ◽  
Vol 95 (12) ◽  
pp. 1215-1218 ◽  
Author(s):  
Amir F. Bahrehbakhsh
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
Early Time ◽  
Energy Model ◽  
Late Time ◽  
Open Universe ◽  
Fifth Dimension ◽  
Flrw Cosmology

We investigate the Friedmann–Lemaître–Robertson–Walker (FLRW) type cosmology of the induced dark energy model and illustrate that the extra terms emerging from the fifth dimension can play the role of dark energy. The model predicts the expansion with deceleration at early time and acceleration in late time for an open universe.

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.

scholarly journals Cosmological degeneracy versus cosmography: A cosmographic dark energy model

2017 ◽  
Vol 26 (03) ◽  
pp. 1750015 ◽  
Author(s):  
Orlando Luongo ◽  
Giovanni Battista Pisani ◽  
Antonio Troisi
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
Free Parameter ◽  
Cold Dark Matter ◽  
Energy Model ◽  
Late Time ◽  
Total Energy Density ◽  
Self Consistent ◽  
Speed Up ◽  
Model Independent

In this work, we use cosmography to alleviate the degeneracy among cosmological models, proposing a way to parametrize matter and dark energy in terms of cosmokinematics quantities. The recipe of using cosmography allows to expand observable quantities in Taylor series and to directly compare those expansions with data. The strategy involves the expansions of [Formula: see text] and [Formula: see text], up to the second-order around [Formula: see text]. This includes additional cosmographic parameters which are fixed by current values of [Formula: see text] and [Formula: see text]. We therefore propose a fully self-consistent parametrization of the total energy density driving the late-time universe speed up. This stratagem does not remove all the degeneracy but enables one to pass from the model-dependent couple of coefficients, [Formula: see text] and [Formula: see text], to model-independent quantities determined from cosmography. Afterwards, we describe a feasible cosmographic dark energy model, in which matter is fixed whereas dark energy evolves by means of the cosmographic series. Our technique provides robust constraints on cosmokinematic parameters, permitting one to separately bound matter from dark energy densities. Our cosmographic dark energy model turns out to be one parameter only, but differently from the lambda cold dark matter ([Formula: see text]CDM) paradigm, it does not contain ansatz on the dark energy form. In addition, we even determine the free parameter of our model in suitable [Formula: see text] intervals through Monte Carlo analyses based on the Metropolis algorithm. We compare our results with the standard concordance model and we find that our treatment seems to indicate that dark energy slightly evolves in time, reducing to a pure cosmological constant only as [Formula: see text].

scholarly journals STATEFINDER PARAMETERS FOR QUINTOM DARK ENERGY MODEL

2005 ◽  
Vol 14 (11) ◽  
pp. 1873-1881 ◽  
Author(s):  
PUXUN WU ◽  
HONGWEI YU
Keyword(s):  
Dark Energy ◽  
Kinetic Energy ◽  
Dark Energy Model ◽  
Scalar Fields ◽  
Energy Model ◽  
The Other ◽  
Energy Term ◽  
Statefinder Parameters ◽  
Energy Models ◽  
Kinetic Energy Term

We perform in this paper a statefinder diagnostic to a dark energy model with two scalar fields, called "quintom," where one of the scalar fields has a canonical kinetic energy term and the other has a negative one. Several kinds of potentials are discussed. Our results show that the statefinder diagnostic can differentiate quintom model with other dark energy models.

STATEFINDER PARAMETERS FOR PHANTOM DARK ENERGY

2006 ◽  
Vol 21 (16) ◽  
pp. 1305-1311 ◽  
Author(s):  
PUXUN WU ◽  
HONGWEI YU
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
Energy Model ◽  
Field Potentials ◽  
Statefinder Parameters ◽  
Phantom Field ◽  
Energy Models ◽  
Phantom Dark Energy ◽  
The Universe

The statefinder parameters were introduced recently to differentiate different dark energy models. In this paper we perform a statefinder diagnostic to the phantom dark energy model with two different phantom field potentials. Our results show that the statefinder diagnostic is rather robust in differentiating not only different dark energy models but also the same kind of models with different potentials which lead to different fate of the universe.

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