scholarly journals HOLOGRAPHIC INTERACTING DARK ENERGY IN THE BRANEWORLD COSMOLOGY

2007 ◽  
Vol 22 (35) ◽  
pp. 2631-2645 ◽  
Author(s):  
KYOUNG YEE KIM ◽  
HYUNG WON LEE ◽  
YUN SOO MYUNG
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cold Dark Matter ◽  
Equations Of State ◽  
Brane Cosmology ◽  
General Decay Rate ◽  
Braneworld Cosmology ◽  
State Formula ◽  
Unified Description

We investigate a model of brane cosmology to find a unified description of the radiation-matter-dark energy universe. It is of the interacting holographic dark energy with a bulk-holographic matter χ. This is a five-dimensional cold dark matter, which plays a role of radiation on the brane. Using the effective equations of state [Formula: see text] instead of the native equations of state ωΛ, we show that this model cannot accommodate any transition from the dark energy with [Formula: see text] to the phantom regime [Formula: see text]. Furthermore, the case of interaction between four-dimensional cold dark matter and five-dimensional cold dark matter is considered for completeness. Here we find that the redshift of matter-radiation equality z eq is the same order as [Formula: see text]. Finally, we obtain a general decay rate Γ which is suitable for describing all interactions.

scholarly journals TOWARDS CLASSIFICATION OF SIMPLE DARK ENERGY COSMOLOGICAL MODELS

2007 ◽  
Vol 04 (02) ◽  
pp. 313-323 ◽  
Author(s):  
MAREK SZYDLOWSKI ◽  
ALEKSANDRA KUREK
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cold Dark Matter ◽  
Friedmann Equation ◽  
Chaplygin Gas ◽  
Generalized Chaplygin Gas ◽  
Cosmological Time ◽  
Energy Models ◽  
State Formula ◽  
The Universe

We characterize a class of simple FRW models filled by both dark energy and dark matter in notion of a single potential function of the scale factor a(t); t is the cosmological time. It represents the potential of a fictitious particle — Universe moving in 1-dimensional well V(a) which the positional variable mimics the evolution of the Universe. Then the class of all dark energy models (called a multiverse) can be regarded as a Banach space naturally equipped in the structure of the Sobolev metric. In this paper, we explore the notion of C1 metric introduced in the multiverse which measures distance between any two dark energy models. If we choose cold dark matter as a reference, then we can find how far apart are different models offering explanation of the present accelerating expansion phase of the Universe. We consider both models with dark energy (models with the generalized Chaplygin gas, models with variable coefficient equation of state [Formula: see text] parameterized by redshift z, models with phantom matter) as well as models based on some modification of Friedmann equation (Cardassian models, Dvali–Gabadadze–Porrati brane models). We argue that because observational data still favor the ΛCDM model, all reasonable dark energy models should belong to the nearby neighborhood of this model.

scholarly journals Unifying dark matter and dark energy with non-canonical scalars

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Swagat S. Mishra ◽  
Varun Sahni
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
General Condition ◽  
Cold Dark Matter ◽  
Scalar Fields ◽  
Kinetic Term ◽  
Potential Term ◽  
Small Scales ◽  
Type Potential

AbstractNon-canonical scalar fields with the Lagrangian $${{\mathcal {L}}} = X^\alpha - V(\phi )$$ L = X α - V ( ϕ ) , possess the attractive property that the speed of sound, $$c_s^{2} = (2\,\alpha - 1)^{-1}$$ c s 2 = ( 2 α - 1 ) - 1 , can be exceedingly small for large values of $$\alpha $$ α . This allows a non-canonical field to cluster and behave like warm/cold dark matter on small scales. We derive a general condition on the potential in order to facilitate the kinetic term $$X^\alpha $$ X α to play the role of dark matter, while the potential term $$V(\phi )$$ V ( ϕ ) playing the role of dark energy at late times. We demonstrate that simple potentials including $$V= V_0\coth ^2{\phi }$$ V = V 0 coth 2 ϕ and a Starobinsky-type potential can unify dark matter and dark energy. Cascading dark energy, in which the potential cascades to lower values in a series of discrete steps, can also work as a unified model.

scholarly journals MASSIVE GRAVITONS DARK MATTER SCENARIO REVISITED

2012 ◽  
Vol 27 (26) ◽  
pp. 1250146 ◽  
Author(s):  
HYUNG WON LEE ◽  
KYOUNG YEE KIM ◽  
YUN SOO MYUNG
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cold Dark Matter ◽  
Equations Of State ◽  
Massive Graviton ◽  
The Past ◽  
Energy Models ◽  
Phantom Phase

We reexamine the massive graviton dark matter scenario (MGCDM) which was recently considered as an alternative to dark energy models. When introducing the native and effective equations of state (EoS), it is shown that there is no phantom phase in the evolution toward the far past. Also we show that the past accelerating phase arises from the interaction between massive graviton and cold dark matter.

Microscopic wormholes, extra-dimensions and cold dark matter from N = 2 maximal supergravity with Gauss–Bonnet corrections

2021 ◽  
pp. 2150042
Author(s):  
Rami Ahmad El-Nabulsi
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cosmological Model ◽  
Extra Dimensions ◽  
Cold Dark Matter ◽  
Traversable Wormhole ◽  
Maximal Supergravity ◽  
The Universe

In this paper, we have discussed a (1 + 9)-dimensional open cosmological model motivated from N = 2 maximal supergravity arguments characterized by the presence of a wormhole connected to the extra dimensions part and a Gauss–Bonnet (GB) curvature corrections. The universe is dominated by dark energy and cold dark matter (CDM) which emerged from extra dimensions as supported by recent phenomenological and observational arguments. By assuming that the wormhole in the outer/inner regions of the halos of galaxies is characterized by a CDM profile density, it was revealed that the universe is expanding acceleratedly with time, dominated by a microscopic traversable wormhole and dark energy. The role of the dominance of the GB term is discussed and the model is confronted with astrophysical observations.

scholarly journals Observational constraints of a new unified dark fluid and the H0 tension

2019 ◽  
Vol 490 (2) ◽  
pp. 2071-2085 ◽  
Author(s):  
Weiqiang Yang ◽  
Supriya Pan ◽  
Andronikos Paliathanasis ◽  
Subir Ghosh ◽  
Yabo Wu
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Early Time ◽  
Observational Constraints ◽  
Minimal Extension ◽  
Energy Evolution ◽  
The Universe ◽  
Different Sources

ABSTRACT Unified cosmological models have received a lot of attention in astrophysics community for explaining both the dark matter and dark energy evolution. The Chaplygin cosmologies, a well-known name in this group have been investigated matched with observations from different sources. Obviously, Chaplygin cosmologies have to obey restrictions in order to be consistent with the observational data. As a consequence, alternative unified models, differing from Chaplygin model, are of special interest. In the present work, we consider a specific example of such a unified cosmological model, that is quantified by only a single parameter μ, that can be considered as a minimal extension of the Λ-cold dark matter cosmology. We investigate its observational boundaries together with an analysis of the universe at large scale. Our study shows that at early time the model behaves like a dust, and as time evolves, it mimics a dark energy fluid depicting a clear transition from the early decelerating phase to the late cosmic accelerating phase. Finally, the model approaches the cosmological constant boundary in an asymptotic manner. We remark that for the present unified model, the estimations of H0 are slightly higher than its local estimation and thus alleviating the H0 tension.

Cold dark matter and dark energy

2012 ◽  
pp. 369-381
Author(s):  
David H. Lyth ◽  
Andrew R. Liddle
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cold Dark Matter

Pilgrim dark energy models in fractal universe

2016 ◽  
Vol 26 (06) ◽  
pp. 1750049 ◽  
Author(s):  
Abdul Jawad ◽  
Shamaila Rani ◽  
Ines G. Salako ◽  
Faiza Gulshan
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cold Dark Matter ◽  
Accelerated Expansion ◽  
Freezing And Thawing ◽  
Eos Parameter ◽  
Pilgrim Dark Energy ◽  
Energy Models ◽  
Expansion Behavior ◽  
The Universe

We discuss the cosmological implications of interacting pilgrim dark energy (PDE) models (with Hubble, Granda–Oliveros and generalized ghost cutoffs) with cold dark matter ([Formula: see text]CDM) in fractal cosmology by assuming the flat universe. We observe that the Hubble parameter lies within observational suggested ranges while deceleration parameter represents the accelerated expansion behavior of the universe. The equation of state (EoS) parameter ([Formula: see text]) corresponds to the quintessence region and phantom region for different cases of [Formula: see text]. Further, we can see that [Formula: see text]–[Formula: see text] (where prime indicates the derivative with respect to natural logarithmic of scale factor) plane describes the freezing and thawing regions and also corresponds to [Formula: see text] limit for some cases of [Formula: see text] (PDE parameter). It is also noted that the [Formula: see text]–[Formula: see text] (state-finder parameters) plane corresponds to [Formula: see text] limit and also shows the Chaplygin as well as phantom/quintessence behavior. It is observed that pilgrim dark energy models in fractal cosmology expressed the consistent behavior with recent observational schemes.

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.

Sign in / Sign up

Export Citation Format

Share Document