Generic scenarios of the accelerating Universe

Szydłowski, Marek

doi:10.1007/s10509-012-1005-x

Cited by 3 publications

(1 citation statement)

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“…We perform a phase-space analysis of Einstein-NED cosmology without a matter source and including it. The advantage of the using phase-space analysis [41][42][43][44][45][46][47][48][49][81][82][83][84][85][86][87][88][89][90][91] is that one can do more stability analysis with using visual plots using the trajectories in geometrical way so that it becomes easy to observe the property with the help of the attractors which are the most easily seen experimentally [92]. On the other hand, conceptually using NED has the advantage that no need to use some exotic fields such as scalar fields, branes or extra dimensions, it is just photon fields, and it is well known also in nonlinear optics which studying behavior of light in nonlinear media and also nonlinear collision of particles in quantum electrodynamics [93][94][95][96][97][98][99].…”

Section: Introductionmentioning

confidence: 99%

Falsifying cosmological models based on a non-linear electrodynamics

et al. 2018

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Recently, the nonlinear electrodynamics (NED) has been gaining attention to generate primordial magnetic fields in the Universe and also to resolve singularity problems. Moreover, recent works have shown the crucial role of the NED on the inflation. This paper provides a new approach based on a new model of NED as a source of gravitation to remove the cosmic singularity at the big bang and explain the cosmic acceleration during the inflation era on the background of stochastic magnetic field. Also, we found a realization of a cyclic Universe, free of initial singularity, due to the proposed NED energy density. In addition, we explore whether a NED field without or with matter can be the origin of the late-time acceleration. For this we obtain explicit equations for H (z) and perform a MCMC analysis to constrain the NED parameters by using 31 observational Hubble data (OHD) obtained from cosmic chronometers covering the redshift range 0 < z < 1.97; and with the joint-light-analysis (JLA) SNIa compilation consisting in 740 data points in the range 0.01 < z < 1.2. All our constraints on the current magnetic field give B 0 ∼ 10 −31 cm −1 , which are larger than the upper limit 10 −33 cm −1 by the Planck satellite implying that NED cosmologies could not be suitable to explain the Universe late-time dynamics. However, the current data is able to falsify the scenario at late times. Indeed, one is able to reconstruct the deceleration parameter q(z) using the best fit values of the parameters obtained from OHD and SNIa data a e-mail: ali.ovgun@pucv.cl URL: https://www.aovgun.com b e-mail: genly.leon@ucn.cl c e-mail: juan.magana@uv.cl d e-mail: kimet.jusufi@unite.edu.mk sets. If the matter component is not included, the data sets predict an accelerated phase in the early Universe, but a non accelerated Universe is preferred in the current epoch. When a matter component is included in the NED cosmology, the data sets predict a q(z) dynamics similar to that of the standard model. Moreover, both cosmological data favor up to 2σ confidence levels an accelerating expansion in the current epoch, i.e., the Universe passes of a decelerated phase to an accelerated stage at redshift ∼ 0.6. Therefore, although the NED cosmology with dust matter predict a value B 0 higher than the one measured by Planck satellite, it is able to drive a late-time cosmic acceleration which is consistent with our dynamical systems analysis and it is preferred by OHD and SNIa data sets.

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Section: Introductionmentioning

confidence: 99%

Falsifying cosmological models based on a non-linear electrodynamics

et al. 2018

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Phase space analysis of the bouncing universe with stringy effects

2023

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Scalar field cosmology — geometry of dynamics

Szydłowski

Hrycyna

Stachowski

2014

Int. J. Geom. Methods Mod. Phys.

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We study the Scalar Field Cosmology (SFC) using the geometric language of the phase space. We define and study an ensemble of dynamical systems as a Banach space with a Sobolev metric. The metric in the ensemble is used to measure a distance between different models. We point out the advantages of visualization of dynamics in the phase space. It is investigated the genericity of some class of models in the context of fine tuning of the form of the potential function in the ensemble of SFC. We also study the symmetries of dynamical systems of SFC by searching for their exact solutions. In this context, we stressed the importance of scaling solutions. It is demonstrated that scaling solutions in the phase space are represented by unstable separatrices of the saddle points. Only critical point itself located on two-dimensional stable submanifold can be identified as scaling solution. We have also found a class of potentials of the scalar fields forced by the symmetry of differential equation describing the evolution of the Universe. A class of potentials forced by scaling (homology) symmetries was given. We point out the role of the notion of a structural stability in the context of the problem of indetermination of the potential form of the SFC. We characterize also the class of potentials which reproduces the ΛCDM model, which is known to be structurally stable. We show that the structural stability issue can be effectively used is selection of the scalar field potential function. This enables us to characterize a structurally stable and therefore a generic class of SFC 1460012-1 Int. J. Geom. Methods Mod. Phys. 2014.11. Downloaded from www.worldscientific.com by MCMASTER UNIVERSITY on 03/13/15. For personal use only. M. Szyd lowski, O. Hrycyna & A. Stachowski models.We have found a nonempty and dense subset of structurally stable models. We show that these models possess symmetry of homology.

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Generic scenarios of the accelerating Universe

Cited by 3 publications

References 38 publications

Falsifying cosmological models based on a non-linear electrodynamics

Falsifying cosmological models based on a non-linear electrodynamics

Phase space analysis of the bouncing universe with stringy effects

Scalar field cosmology — geometry of dynamics

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