Friedmann–Robertson–Walker accelerating Universe with interactive dark energy (original) (raw)

A dark energy quintessence model of the universe

Modern Physics Letters A

In this paper, we have presented a model of the Friedmann–Lemaitre–Robertson–Walker (FLRW) universe filled with matter and dark energy (DE) fluids by assuming an ansatz that deceleration parameter (DP) is a linear function of the Hubble constant. This results in a time-dependent DP having decelerating–accelerating transition phase of the universe. This is a quintessence model [Formula: see text]. The quintessence phase remains for the period [Formula: see text]. The model is shown to satisfy current observational constraints. Various cosmological parameters relating to the history of the universe have been investigated.

Accelerating universe with binary mixture of bulk viscous fluid and dark energy

International Journal of Modern Physics A, 2021

In this paper, we have proposed a model of accelerating universe with binary mixture of bulk viscous fluid and dark energy (DE) and probed the model parameters: present values of Hubble’s constant [Formula: see text], equation of state paper of DE [Formula: see text] and density parameter of DE [Formula: see text] with recent observational [Formula: see text] data (OHD) as well as joint Pantheon compilation of SN Ia data and OHD. Using cosmic chronometric technique, we obtain [Formula: see text] and [Formula: see text] by restricting our derived model with recent OHD and joint Pantheon compilation SN Ia data and OHD, respectively. The present age of the universe in derived model is estimated as [Formula: see text]. Also, we observe that derived model represents a model of transitioning universe with transition redshift [Formula: see text]. We have constrained the present value of jerk parameter as [Formula: see text] with joint OHD and Pantheon data. From this analysis, we observed ...

FRW dark energy cosmological model with hybrid expansion law

New Astronomy, 2019

In this work, we study a cosmological model of spatially homogeneous and isotropic accelerating universe which exhibits a transition from deceleration to acceleration. For this, Friedmann Robertson Walker(FRW) metric is taken and Hybrid expansion law a(t) = t α exp(βt) is proposed and derived. We consider the universe to be filled with two types of fluids barotropic and dark energy which have variable equations of state. The evolution of dark energy, Hubble, and deceleration parameters etc., have been described in the form of tables and figures. We consider 581 data's of observed values of distance modulus of various SNe Ia type supernovae from union 2.1 compilation to compare our theoretical results with observations and found that model satisfies current observational constraints. We have also calculated the time and redshift at which acceleration in the Universe had commenced.

Some FRW models of accelerating universe with dark energy

Astrophysics and Space Science 332 (2011) 449-454 [arXiv:1010.0672v1 [gr-qc]]

The paper deals with a spatially homogeneous and isotropic FRW space-time filled with perfect fluid and dark energy components. The two sources are assumed to interact minimally, and therefore their energy momentum tensors are conserved separately. A special law of variation for the Hubble parameter proposed by Berman (Nuovo Cimento B 74:182, 1983) has been utilized to solve the field equations. The Berman’s law yields two explicit forms of the scale factor governing the FRW space-time and constant values of deceleration parameter. The role of dark energy with variable equation of state parameter has been studied in detail in the evolution of FRW universe. It has been found that dark energy dominates the universe at the present epoch, which is consistent with the observations. The physical behavior of the universe has been discussed in detail.

Two-fluid atmosphere from decelerating to accelerating Friedmann–Robertson–Walker dark energy models

Indian Journal of Physics, 2013

The evolution of the dark energy parameter within the scope of a spatially homogeneous and isotropic Friedmann-Robertson-Walker (FRW) model filled with perfect fluid and dark energy components is studied by generalizing the recent results (Amirhashchi et al. in Int. J. Theor. Phys. 50: 3529, 2011b). The two sources are claimed to interact minimally so that their energy momentum tensors are conserved separately. The conception of time-dependent deceleration parameter (DP) with some suitable assumption yields an average scale factor a = [sinh(αt)] 1 n , with α and n being positive arbitrary constants. For 0 < n ≤ 1, this generates a class of accelerating models while for n > 1, the models of universe exhibit phase transition from early decelerating phase to present accelerating phase which is supported with the results from recent astrophysical observations. It is observed that the transition red shift (zt) for our derived model with q0 = −0.73 is ∼ = 0.32. This is in good agreement with the cosmological observations in the literature. Some physical and geometric properties of the model along with physical acceptability of cosmological solutions have been discussed in detail.

An FLRW interacting dark energy model of the Universe

New Astronomy

In this paper, we have presented an FLRW universe containing two-fluids (baryonic and dark energy), with a deceleration parameter (DP) having a transition from past decelerating to the present accelerating universe. In this model, dark energy (DE) interacts with dust to produce a new law for the density. As per our model, our universe is at present in a phantom phase after passing through a quintessence phase in the past. The physical importance of the two-fluid scenario is described in various aspects. The model is shown to satisfy current observational constraints such as recent Planck results. Various cosmological parameters relating to the history of the universe have been investigated.

A Dynamic Model of Accelerated Expansion of Universe

We establish a dynamic effective model for explaining the accelerated expansion of the universe. The model is based on the quantum theory of gravity that predicts the existence of the negative gravitational charges. We show that the results of this model are equivalent to that of the dark energy models, and therefore, consistent with the observations. We suggest that the accelerated expansion of the universe is an observational evidence of the existence of the negative gravitational charges. This model predicts that the universe filled with negative gravitational charges is accelerated collapse. Moreover we propose an alternative physical interpretation that the cosmological constant is equivalent to the negative gravitational charges as a source of gravitational fields. This interpretation avoids the fine-tuning problem. This dynamic model predicts that the equation of state, the cosmological constant and the acceleration of the expansion of the universe are time dependent.

Interacting dark energy model for the expansion history of the Universe

Physical Review D, 2006

We explore a model of interacting dark energy where the dark energy density is related by the holographic principle to the Hubble parameter, and the decay of the dark energy into matter occurs at a rate comparable to the current value of the Hubble parameter. We find this gives a good fit to the observational data supporting an accelerating Universe, and the model represents a possible alternative interpretation of the expansion history of the Universe. 95.36.+x

Interacting Holographic Dark Energy Model and Accelerated Expansion of the Universe

arXiv: General Relativity and Quantum Cosmology, 2019

We study the evolution of the universe by assuming an integrated model, which involves interacting dark energy and holographic principle with Hubble scale as IR cutoff. First we determined the interaction rate at which relativistic matter is converting to dark energy. In the next step, we evaluated the equation of state parameter which describes the nature of dark energy. Our result predicts that the present state of the universe is phantom dominated which is highly likely by observational data. Again our analysis successfully addresses the problem of present accelerated expansion of the universe. We also found that the universe was previously undergoing a decelerated expansion and transition from deceleration to acceleration occurs at a time of tq=0approx0.798t0t_{q=0}\approx 0.798 t_0t_q=0approx0.798t0, where t0t_0t_0 is the present age of the universe.

The dark energy–dominated Universe

Astroparticle Physics, 2005

In this paper we investigate the epochs in which the Universe started accelerating and when it began to become dark energy-dominated (i.e., the dynamics of the expansion of the Universe dominated by the dark energy). We provide analytic expressions to calculate the redshifts of these epochs as a function of density parameters. Moreover, we review and discuss cosmological models with a dark energy component, which can have an interesting characteristic, namely, they never stop accelerating. This holds even if the Universe is at present time either flat, open, or closed. If the dark energy is the cosmological constant the Universe will eventually end up undergoing an exponentially expansion phase, and the total density parameter converging to X = 1. This is exactly what is considered in inflationary scenario to generate the initial conditions for the big bang. One can then argue that the Universe begun with an inflationary phase and will end up with another inflationary phase. Thus, it follows that in both the early and the late Universe X ! 1. We also discuss the above issues in the context of the XCDM parametrization.