Viscous dark energy and phantom evolution

Cataldo, Mauricio; Cruz, Norman; Lepe, Samuel

doi:10.1016/j.physletb.2005.05.029

Cited by 156 publications

(122 citation statements)

References 13 publications

Supporting

Mentioning

119

Contrasting

Order By: Relevance

“…Cataldo et al [35] have analysed the possibility of late acceleration, using Israel-Stewart formalism of bulk viscosity. In this work, the authors have used an ansatz for the Hubble parameter (inspired from the non-causal theory), and they have shown that the universe might have undergone a transition to the phantom behaviour leading to big-rip singularity.…”

Section: Introductionmentioning

confidence: 99%

Bulk viscous matter and recent acceleration of the universe based on causal viscous theory

2017

View full text Add to dashboard Cite

The evolution of the bulk viscous matter dominated universe has been analysed using the full causal theory for the evolution of the viscous pressure in the context of the recent acceleration of the universe. The form of the viscosity is taken as ξ = αρ 1/2 . We obtained analytical solutions for the Hubble parameter and scale factor of the universe. The model parameters have been computed using the observational data. The evolution of the prominent cosmological parameters was obtained. The age of the universe for the best estimated model parameters is found to be less than observational value. The viscous matter behaves like a stiff fluid in the early phase and evolves to a negative pressure fluid in the later phase. The equation of state is found to be stabilised with value ω > −1. The local as well as generalised second law of thermodynamics is satisfied. The statefinder diagnostic shows that this model is distinct from the standard ΛCDM. One of the marked deviations seen in this model to be compared with the corresponding model using the Eckart approach is that in this model the bulk viscosity decreases with the expansion of the universe, while in the Eckart formalism it increases from negative values in the early universe towards positive values.

show abstract

Section: Introductionmentioning

confidence: 99%

Bulk viscous matter and recent acceleration of the universe based on causal viscous theory

2017

View full text Add to dashboard Cite

show abstract

“…In spite of the said limitations, because of simplicity of approach, Eckart theory has been adopted widely in the study of the accelerating universe filled with bulk viscous fluid (e.g. [60,62,63]). In the present work, we consider that in addition to the viscous EHRDE the universe also contains barotropic fluid, and consequently the Friedman equation and the corresponding equations of motion take the form [62]…”

Section: Eckart Approachmentioning

confidence: 99%

Viscous extended holographic Ricci dark energy in the framework of standard Eckart theory

Chattopadhyay¹

2016

Mod. Phys. Lett. A

View full text Add to dashboard Cite

In the present work we report a study on the viscous extended holographic Ricci dark energy (EHRDE) model under the assumption of existence of bulk viscosity in the linear barotropic fluid and the EHRDE in the framework of standard Eckart theory of relativistic irreversible thermodynamics and it has been observed that the non-equilibrium bulk viscous pressure is significantly smaller than the local equilibrium pressure. We have studied the equation of state (EoS) parameter and observed that the EoS behaves like "quintom" and is consistent with the constraints set by observational data sets from SNLS3, BAO and Planck + WMAP9 + WiggleZ measurements in the reference S. Kumar and L. Xu, Phys. Lett. B,737, 244 (2014). Analysis of statefinder parameters has shown the possibility of attainment of ΛCDM phase under current model and at the same time it has been pointed out that the for z = 0 i.e. current universe, the statefinder pair is different from that of ΛCDM and the ΛCDM can be attained in a later stage of the universe. An analysis of stability has shown that although the viscous EHRDE along with viscous barotropic is classically unstable in the present epoch, it can lead to a stable universe in very late stage.Considering an universe enveloped by event horizon we have observed validity of generalized second law of thermodynamics.

show abstract

“…The dark energy phenomenon as an effect of the bulk viscosity in the cosmic medium has been first investigated in [48]. All these cited works are pioneer papers on the cosmological bulk viscosity, but it is also worth noting some recent applications of viscous fluids as candidates for dark matter [49], dark energy [50][51][52][53][54] or unified models [55][56][57][58][59][60], i.e., when a single substance plays the role of both dark matter and dark energy simultaneously. Indeed, it has been shown that for an appropriate viscosity coefficient, an accelerating cosmology can be achieved without the need of a cosmological constant [61][62][63][64].…”

Section: Introductionmentioning

confidence: 99%

Friedmann model with viscous cosmology in modified $$f(R,T)$$ f ( R , T ) gravity theory

2014

View full text Add to dashboard Cite

In this paper, we introduce the bulk viscosity in the formalism of modified gravity theory in which the gravitational action contains a general function f (R, T ), where R and T denote the curvature scalar and the trace of the energy-momentum tensor, respectively, within the framework of a flat Friedmann-Robertson-Walker model. As an equation of state for a prefect fluid, we take p = (γ − 1)ρ, where 0 ≤ γ ≤ 2 and a viscous term as a bulk viscosity due to the isotropic model, of the form ζ = ζ 0 + ζ 1 H , where ζ 0 and ζ 1 are constants, and H is the Hubble parameter. The exact non-singular solutions to the corresponding field equations are obtained with non-viscous and viscous fluids, respectively, by assuming a simplest particular model of the form of f (R, T ) = R + 2 f (T ), where f (T ) = αT (α is a constant). A big-rip singularity is also observed for γ < 0 at a finite value of cosmic time under certain constraints. We study all possible scenarios with the possible positive and negative ranges of α to analyze the expansion history of the universe. It is observed that the universe accelerates or exhibits a transition from a decelerated phase to an accelerated phase under certain constraints of ζ 0 and ζ 1 . We compare the viscous models with the non-viscous one through the graph plotted between the scale factor and cosmic time and find that the bulk viscosity plays a major role in the expansion of the universe. A similar graph is plotted for the deceleration parameter with non-viscous and viscous fluids and we find a transition from decelerated to accelerated phase with some form of bulk viscosity.

show abstract

Viscous dark energy and phantom evolution

Cited by 156 publications

References 13 publications

Bulk viscous matter and recent acceleration of the universe based on causal viscous theory

Bulk viscous matter and recent acceleration of the universe based on causal viscous theory

Viscous extended holographic Ricci dark energy in the framework of standard Eckart theory

Friedmann model with viscous cosmology in modified $$f(R,T)$$ f ( R , T ) gravity theory

Contact Info

Product

Resources

About