Equation of state for Universe from similarity symmetries

Abstract

In this paper we proposed to use the group of analysis of symmetries of the dynamical system to describe the evolution of the Universe. This methods is used in searching for the unknown equation of state. It is shown that group of symmetries enforce the form of the equation of state for noninteracting scaling multifluids. We showed that symmetries give rise the equation of state in the form $p=-\Lambda +w_1\rho (a)+w_2{a}^{\beta }+0$ and energy density $\rho =\Lambda +{\rho }_{01}{a}^{-3(1+w)}+{\rho }_{02}{a}^{\beta }+{\rho }_{03}{a}^{-3}$, which is commonly used in cosmology. The FRW model filled with scaling fluid (called homological) is confronted with the observations of distant type Ia supernovae. We found the class of model parameters admissible by the statistical analysis of SNIa data. We showed that the model with scaling fluid fits well to supernovae data. We found that ${\Omega }_{\text{m},0}\simeq 0.4$ and $n\simeq -1$ ($\beta =-3n$), which can correspond to (hyper) phantom fluid, and to a high density universe. However if we assume prior that ${\Omega }_{\text{m},0}=0.3$ then the favoured model is close to concordance $\Lambda$CDM model. Our results predict that in the considered model with scaling fluids distant type Ia supernovae should be brighter than in $\Lambda$CDM model, while intermediate distant SNIa should be fainter than in $\Lambda$CDM model. We also investigate whether the model with scaling fluid is actually preferred by data over $\Lambda$CDM model. As a result we find from the Akaike model selection criterion prefers the model with noninteracting scaling fluid.

accepted for publication version

References in corpus (7)

• Quantum escape of sudden future singularity
• Bouncing Universes with Varying Constants
• Testing for double inflation with WMAP
• Quantum Cosmological Models
• Can the initial singularity be detected by cosmological tests?
• Perturbations in Bouncing Cosmological Models
• Production of photons in a bouncing universe

Cited by in corpus (27)

• New Schwarzschild-like solutions in f(T) gravity through Noether symmetries
• Noether symmetries and analytical solutions in f(T)-cosmology: A complete study
• Correspondence between kinematical backreaction and scalar field cosmologies - the `morphon field'
• Noether symmetry approach in phantom quintessence cosmology
• Dynamical analysis in scalar field cosmology
• Constraints and analytical solutions of $f(R)$ theories of gravity using Noether symmetries
• Phase Space Analysis of the Accelerating Multi-fluid Universe
• Scalar-Tensor Gravity Cosmology: Noether symmetries and analytical solutions
• Scalar Field Dark Energy Perturbations and their Scale Dependence
• Dynamical symmetries and observational constraints in scalar field cosmology
• Classical and Quantum Solutions in Brans-Dicke Cosmology with a Perfect Fluid
• Statefinder diagnosis and the interacting ghost model of dark energy
• Scalar Field Cosmology -- Geometry of Dynamics
• A study of phantom scalar field cosmology using Lie and Noether symmetries
• Turning a Newtonian analogy for FLRW cosmology into a relativistic problem
• Inflation and Bounce from Classical and Loop Quantum Cosmology Imperfect Fluids
• Evolution of perturbations in distinct classes of canonical scalar field models of dark energy
• Multi-fluid cosmology in Einstein gravity: analytical solutions
• Using Noether symmetries to specify f(R) gravity
• Quintom cosmological model and some possible solutions using Lie and Noether symmetries
• A symmetry of the spatially flat Friedmann equations with barotropic fluid
• A new symmetry of the spatially flat Einstein-Friedmann equations
• Cosmological analogies, Lagrangians, and symmetries for convective-radiative heat transfer
• Variable $G$ and $\Lambda$ gravity theory and analytical Cosmological Solutions using Noether symmetry approach
• Scaling attractors for quintessence in flat universe with cosmological term
• About Bianchi I with VSL
• Classical and quantum cosmology in $f(T)$-gravity theory: A Noether symmetry approach