Stability analysis and constraints on interacting viscous cosmology

Hernández-Almada, A.; García‐Aspeitia, Miguel A.; Magaña, Juan; Motta, V.

doi:10.1103/physrevd.101.063516

Cited by 23 publications

(26 citation statements)

References 73 publications

(84 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For instance, bulk viscosity coefficient has been modelled as a constant [30][31][32][33], polynomials [34][35][36], and hyperbolic [36,37] functions. Moreover, it allows easily to explore the presence of interacting terms in the viscous fluid [38]. Because the non perfect fluid should satisfy the near equilibrium condition of thermodynamics, the pressure of the fluid must be greater than the one generated by the viscosity.…”

Section: Introductionmentioning

confidence: 99%

Constraints and cosmography of $$\Lambda $$CDM in presence of viscosity

2020

Self Cite

View full text Add to dashboard Cite

In this work, we study two scenarios of the Universe filled by a perfect fluid following the traditional dark energy and a viscous fluid as dark matter. In this sense, we explore the most simple case for the viscosity in the Eckart formalism, a constant, and then, a polynomial function of the redshift. We constrain the phase-space of the model parameters by performing a Bayesian analysis based on Markov Chain Monte Carlo method and using the latest data of the Hubble parameter (OHD), Type Ia Supernovae (SNIa) and Strong Lensing Systems. The first two samples cover the region $$0.01<z<2.36$$ 0.01 < z < 2.36 . Based on AIC, we find equally support of these viscous models over Lambda-Cold Dark Matter (LCDM) taking into account OHD or SNIa. On the other hand, we reconstruct the cosmographic parameters (q, j, s, l) and find good agreement to LCDM within up to $$3\sigma $$ 3 σ CL. Additionally, we find that the cosmographic parameters and the acceleration-deceleration transition are sensible to the parameters related to the viscosity coefficient, making of the viscosity an interesting physical mechanism to modified them.

show abstract

Section: Introductionmentioning

confidence: 99%

Constraints and cosmography of $$\Lambda $$CDM in presence of viscosity

2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…As we are assuming a FLRW Universe, the bulk viscosity coefficient is given by = −3ξ H . Even though this formalism has been widely used to describe inflation, late-time acceleration, background and perturbative levels [38,[41][42][43][44][45][46][47][76][77][78][79], there is a fundamental difficulty which is related with its non-causal behavior [80][81][82] (see also Ref. [57] and the references therein) Now, by choosing a reference frame which the hydrodynamics four-velocity u μ is unitary u μ u μ = 1, and considering Eqs.…”

Section: Background Levelmentioning

confidence: 99%

“…Also, an interesting proposal considered an exotic fluid with bulk viscosity. Models assuming this possibility have also been studied in the context of the interaction of DE and DM [13,[38][39][40][41][42]. Moreover, those models could resolve the tension across different probes as the values of the Hubble constant, and the tension associated with values matter fluctuation amplitude [43].…”

Section: Introductionmentioning

confidence: 99%

Growth of matter perturbations in the extended viscous dark energy models

Silva

2021

Eur. Phys. J. C

View full text Add to dashboard Cite

In this work, we study the extended viscous dark energy models in the context of matter perturbations. To do this, we assume an alternative interpretation of the flat Friedmann–Lemaître–Robertson–Walker Universe, through the nonadditive entropy and the viscous dark energy. We implement the relativistic equations to obtain the growth of matter fluctuations for a smooth version of dark energy. As result, we show that the matter density contrast evolves similarly to the $$\Lambda $$ Λ CDM model in high redshift; however, in late time, it is slightly different from the standard model. Using the latest geometrical and growth rate observational data, we carry out a Bayesian analysis to constrain parameters and compare models. We see that our viscous models are compatible with cosmological probes, and the $$\Lambda $$ Λ CDM recovered with a $$1\sigma $$ 1 σ confidence level. The viscous dark energy models relieve the tension of $$H_0$$ H 0 in $$2 \sim 3 \sigma $$ 2 ∼ 3 σ . Yet, by involving the $$\sigma _8$$ σ 8 tension, some models can alleviate it. In the model selection framework, the data discards the extended viscous dark energy models.

show abstract

“…In the context of cosmology, the cosmic fluid to a large extent is spatially isotropic and therefore the shear viscosity plays no role in cosmic dynamics. Having said that, the bulk viscosity could play a very important role in governing the cosmic evolution by modifying the background dynamics [16,17]. Some of the earliest works in bulk viscous cosmology dates back to 1970's [18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Late-time viscous cosmology in f(R, T) gravity

2021

View full text Add to dashboard Cite

The article communicates an alternative route to suffice the late-time acceleration considering a bulk viscous fluid with viscosity coefficient ζ = ζ 0 + ζ 1 H + ζ 2 H 2 , where ζ 0 , ζ 1 , ζ 2 are constants in the framework of f (R, T) modified gravity. We presume the f (R, T) functional form to be f = R + 2αT where α is a constant. We then solve the field equations for the Hubble Parameter and study the cosmological dynamics of kinematic variables such as deceleration, jerk, snap and lerk parameters as a function of cosmic time. We observe the deceleration parameter to be highly sensitive to α and undergoes a signature flipping at around t ∼ 10 Gyrs for α = −0.179 which is favored by observations. The EoS parameter for our model assumes values close to −1 at t 0 = 13.7Gyrs which is in remarkable agreement with the latest Planck measurements. Next, we study the evolution of energy conditions and find that our model violate the Strong Energy Condition in order to explain the late-time cosmic acceleration. To understand the nature of dark energy mimicked by the bulk viscous baryonic fluid, we perform some geometrical diagnostics like the {r, s} and {r, q} plane. We found the model to mimic the nature of a Chaplygin gas type dark energy model at early times while a Quintessence type in distant future. Finally, we study the violation of continuity equation for our model and show that in order to explain the cosmic acceleration at the present epoch, energymomentum must violate.

show abstract

Stability analysis and constraints on interacting viscous cosmology

Cited by 23 publications

References 73 publications

Constraints and cosmography of $$\Lambda $$CDM in presence of viscosity

Constraints and cosmography of $$\Lambda $$CDM in presence of viscosity

Growth of matter perturbations in the extended viscous dark energy models

Late-time viscous cosmology in f(R, T) gravity

Contact Info

Product

Resources

About