Exact analytical solution for an Israel-Stewart Cosmology

Cruz, Norman; González, Esteban; Palma, G.

doi:10.48550/arxiv.1812.05009

Cited by 4 publications

(9 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Now, we will briefly discuss the two solutions for Eq. ( 8) found in [35] for s = 1/2 and for the especial cases of γ = 1 and γ = 1.…”

Section: The Novel Cosmological Solutionsmentioning

confidence: 83%

“…We address the reader to see the technical details in ref. [35]. As we shall see in the next section we obtained a novel solution for the special case s = 1/2, which allows an important simplification of Eq.…”

Section: Israel-stewart Formalismmentioning

confidence: 93%

“…( 7), which was used in order to obtain the Eq. ( 16) in [35]. Even more, this solution has three different behaviors depending on the signs of the constants C 1 and C 2 .…”

Section: The Novel Cosmological Solutionsmentioning

confidence: 95%

“…Our aim in this paper is to constraint the respective free parameters of novel and particular exact cosmological solutions, found in [35] for a universe filled only with a dissipative dark matter component. The constraint was done using the supernova Ia (SNe Ia).…”

Section: Introductionmentioning

confidence: 99%

“…In section III we study the novel solution for arbitrary γ and show that the particular solution corresponding to the particular case of dust matter found in [35]. In section IV we constraint the free parameters of the solutions with the observational supernova Ia (SNe Ia) data.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Testing dissipative dark matter in causal thermodynamics

Cruz¹,

González²,

Palma³

2019

Preprint

Self Cite

View full text Add to dashboard Cite

In this paper we study the consistency of a cosmological model, described by a novel exact analytic solution of a universe filled with a dissipative dark matter fluid, in the framework of the causal Israel-Stewart theory, testing it by using Type Ia Supernovae data. The solution is obtained when we assume for the fluid a bulk viscous coefficient with the dependence ξ = ξ0ρ 1/2 , where ρ is the energy density of the fluid. It is further considered a relaxation time τ of the form ξ (ρ+p)τ = c 2 b , where c 2 b is the speed of bulk viscous perturbations, and a barotropic EoS p = (γ − 1) ρ. The constraints found for the parameters of the model allow to obtain exact solutions compatible with an accelerated expansion at late times, after the domination era of the viscous pressure and without the inclusion of a cosmological constant. Nevertheless, the fitted parameter values present drawbacks as a very large non-adiabatic contribution to the speed of sound, and some inconsistencies with the description of the dissipative dark matter as a fluid.

show abstract

“…Now, we will briefly discuss the two solutions for Eq. ( 8) found in [35] for s = 1/2 and for the especial cases of γ = 1 and γ = 1.…”

Section: The Novel Cosmological Solutionsmentioning

confidence: 83%

Section: Israel-stewart Formalismmentioning

confidence: 93%

“…( 7), which was used in order to obtain the Eq. ( 16) in [35]. Even more, this solution has three different behaviors depending on the signs of the constants C 1 and C 2 .…”

Section: The Novel Cosmological Solutionsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Testing dissipative dark matter in causal thermodynamics

Cruz¹,

González²,

Palma³

2019

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

Dynamical system analysis and thermal evolution of the causal dissipative model

Mohan

Krishna

Sasidharan

et al. 2020

Class. Quantum Grav.

View full text Add to dashboard Cite

The dynamical system behaviour and thermal evolution of a homogeneous and isotropic dissipative universe are analyzed. The dissipation is driven by the bulk viscosity and the evolution of bulk viscous pressure is described using the full causal Israel–Stewart theory. We find that for s = 1/2 the model possesses a prior decelerated epoch which is unstable and a stable future accelerated epoch. From the thermodynamic analysis, we have verified that the local as well as the generalised second law of thermodynamics are satisfied throughout the evolution of the universe. We also show that the convexity condition is satisfied at the end stage of the universe which implies an upper bound to the evolution of the entropy. For , the case s < 1/2 is ruled out since it does not predict the conventional evolutionary stages of the universe. On the other hand, the case s > 1/2 does imply a prior decelerated and a late de Sitter epochs, but both of them are unstable fixed points. The thermal evolution corresponding to the same case implies that GSL is satisfied at both the epochs but convexity condition is violated by both, so that entropy growth is unbounded. Hence for s > 1/2 the model does not give a stable evolution of the universe.

show abstract

Cosmological test on viscous bulk models using Hubble parameter measurements and type Ia supernovae data

Hernández-Almada

2019

Eur. Phys. J. C

View full text Add to dashboard Cite

From a phenomenological point of view, we analyze the dynamics of the Universe at late times by introducing a polynomial and hyperbolic bulk viscosity into the Einstein field equations respectively. We constrain their free parameters using the observational Hubble parameter data and the Type Ia Supernovae dataset to reconstruct the deceleration q and the jerk j parameters within the redshift region 0 < z < 2.5. At current epochs, we obtain q 0 = −0.680 +0.085 −0.102 and j 0 = 2.782 +1.198 −0.741 for the polynomial model and q 0 = −0.539 +0.040 −0.038 (−0.594 +0.056 −0.056 ) and j 0 = 0.297 +0.051 −0.050 (1.124 +0.196 −0.178 ) for the tanh (cosh) model. Furthermore, we explore the statefinder diagnostic that gives us evident differences with respect to the concordance model (LCDM). According to our results this kind of models is not supported by the data over LCDM.

show abstract

Exact analytical solution for an Israel-Stewart Cosmology

Cited by 4 publications

References 17 publications

Testing dissipative dark matter in causal thermodynamics

Testing dissipative dark matter in causal thermodynamics

Dynamical system analysis and thermal evolution of the causal dissipative model

Cosmological test on viscous bulk models using Hubble parameter measurements and type Ia supernovae data

Contact Info

Product

Resources

About