scholarly journals Rip brane cosmology from a viscous holographic dark fluid

2020 ◽  
Vol 17 (06) ◽  
pp. 2050087 ◽  
Author(s):  
I. Brevik ◽  
A. V. Timoshkin
Keyword(s):  
Dark Energy ◽  
Energy Conservation ◽  
Bulk Viscosity ◽  
Holographic Dark Energy ◽  
Holographic Principle ◽  
De Sitter ◽  
Brane Cosmology ◽  
Viscous Cosmology ◽  
Dark Fluid ◽  
Analytical Expressions

This paper is devoted to the application of the holographic principle to describe Rip brane cosmological models in the presence of a bulk viscosity. We make use of the generalized infrared-cutoff holographic dark energy, introduced by Nojiri and Odintsov. We consider various examples: Rip brane cosmology corresponding to the Little Rip case, asymptotic de Sitter theory, and the so-called Big Freeze theory leading to a singularity. Analytical expressions for infrared cutoffs, as well as the particle and the future horizons at the brane, are obtained. The equations for energy conservation on the brane within the holographic theory are obtained in each case. The correspondence between viscous cosmology and holographic cosmology on the brane is shown.

scholarly journals Holographic cosmology with two coupled fluids in the presence of viscosity

2021 ◽  
pp. 2150149
Author(s):  
I. Brevik ◽  
A. V. Timoshkin
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Holographic Dark Energy ◽  
Exponential Model ◽  
Point Of View ◽  
Accelerating Universe ◽  
Late Time ◽  
Conservation Of Energy ◽  
Analytical Expressions ◽  
Friedmann Robertson Walker

We explore the cosmological models of the late-time universe based on the holographic principle, taking into account the properties of the viscosity of the dark fluid. We use the mathematical formalism of generalized infrared cutoff holographic dark energy, as presented by Nojiri and Odintsov [Covariant generalized holographic dark energy and accelerating universe, Eur. Phys. J. C 77 (2017) 528]. We consider the Little Rip, the Pseudo Rip, and a bounce exponential model, with two interacting fluids, namely dark energy and dark matter in a spatially-flat Friedmann–Robertson–Walker universe. Within these models, analytical expressions are obtained for infrared cutoffs in terms of the particle horizons. The law of conservation of energy is presented, from a holographic point of view.

scholarly journals Holographic dark energy model in unimodular f(T) gravity

2019 ◽  
Vol 16 (01) ◽  
pp. 1950003
Author(s):  
A. E. Godonou ◽  
M. J. S. Houndjo ◽  
J. Tossa
Keyword(s):  
Dark Energy ◽  
Holographic Dark Energy ◽  
Teleparallel Gravity ◽  
De Sitter ◽  
Holographic Dark Energy Model ◽  
Reconstruction Procedure ◽  
Perfect Agreement ◽  
Text Data ◽  
Viable Model ◽  
Reconstructed Model

This work deals with holographic dark energy in the context of unimodular [Formula: see text] gravity, which is a modification of teleparallel gravity. We develop the general reconstruction procedure of the [Formula: see text] form that can yield the holographic feature of the dark energy. We fit the reconstructed model with the [Formula: see text] data and our results show a perfect agreement with the WMAP9 cosmological observational data, at least for the range [Formula: see text]. We investigate the consistency of the reconstructed model by studying its stability against linear gravitational and matter perturbations, fixing [Formula: see text] to [Formula: see text]. The model presents stability for both de Sitter and power-law solutions and we conclude that it is a good candidate as alternative viable model for characterizing holographic dark energy.

scholarly journals New holographic dark energy model inspired by the DGP braneworld

2016 ◽  
Vol 25 (02) ◽  
pp. 1650018 ◽  
Author(s):  
A. Sheykhi ◽  
M. H. Dehghani ◽  
S. Ghaffari
Keyword(s):  
Dark Energy ◽  
Energy Density ◽  
Holographic Dark Energy ◽  
Apparent Horizon ◽  
Brane Cosmology ◽  
Eos Parameter ◽  
New Model ◽  
Hubble Radius ◽  
Area Law ◽  
Dgp Braneworld

The energy density of the holographic dark energy (HDE) is based on the area law of entropy, and thus any modification of the area law leads to a modified holographic energy density. Inspired by the entropy expression associated with the apparent horizon of a Friedmann–Robertson–Walker (FRW) universe in DGP braneworld, we propose a new model for the HDE in the framework of DGP brane cosmology. We investigate the cosmological consequences of this new model and calculate the equation of state (EoS) parameter by choosing the Hubble radius, [Formula: see text], as the system’s IR cutoff. Our study show that, due to the effects of the extra dimension (bulk), the identification of IR cutoff with Hubble radius, can reproduce the present acceleration of the universe expansion. This is in contrast to the ordinary HDE in standard cosmology which leads to the zero EoS parameter in the case of choosing the Hubble radius as system’s IR cutoff in the absence of interaction between dark matter (DM) and dark energy (DE).

scholarly journals An interacting holographic dark energy model within an induced gravity brane

2020 ◽  
Vol 29 (09) ◽  
pp. 2050066
Author(s):  
Moulay-Hicham Belkacemi ◽  
Zahra Bouabdallaoui ◽  
Mariam Bouhmadi-López ◽  
Ahmed Errahmani ◽  
Taoufik Ouali
Keyword(s):  
Dark Energy ◽  
Holographic Dark Energy ◽  
Late Time ◽  
De Sitter ◽  
Ricci Dark Energy ◽  
Induced Gravity ◽  
Big Rip ◽  
Dark Energy Component ◽  
Braneworld Model ◽  
The Universe

In this paper, we present a model for the late-time evolution of the universe where a dark energy-dark matter interaction is invoked. Dark energy is modeled through an holographic Ricci dark energy component. The model is embedded within an induced gravity braneworld model. For suitable choices of the interaction coupling, the big rip and little rip induced by the holographic Ricci dark energy, in a relativistic model and in an induced gravity braneworld model, are removed. In this scenario, the holographic dark energy will have a phantom like behavior even though the brane is asymptotically de Sitter.

scholarly journals A Thermodynamic Approach to Holographic Dark Energy

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Orlando Luongo
Keyword(s):  
Dark Energy ◽  
Holographic Dark Energy ◽  
Cosmological Models ◽  
Holographic Principle ◽  
Thermodynamic Approach ◽  
Free Term ◽  
Spatial Curvature ◽  
Massless Particles ◽  
Information Density ◽  
Minimal Information

We propose a method to relate the holographic minimal information density to de Broglie’s wavelength at a given universe temperature T. To figure this out, we assume that the thermal length of massive and massless constituents represents the cut-off scale of the holographic principle. To perform our analysis, we suppose two plausible universe volumes, that is, the adiabatic and the horizon volumes, that is, V∝a3 and V∝H-3, respectively, assuming zero spatial curvature. With these choices in mind, we evaluate the thermal lengths for massive and massless particles and we thus find two cosmological models associated with late and early cosmological epochs. We demonstrate that both models depend upon a free term β which enters the temperature parametrization in terms of the redshift z. For the two treatments, we show evolving dark energy terms which can be compared with the ωCDM quintessence paradigm when the barotropic factor takes the formal values ω0=-1/3(2+β) and ω0=-1/3(1+2β), respectively, for late and early eras. From our analyses, we nominate the two models as viable alternatives to dark energy determined from thermodynamics in the field of the holographic principle.

Unification of dark energy and dark matter based on the Petrov classification and space-time symmetry

2016 ◽  
Vol 31 (02n03) ◽  
pp. 1641005 ◽  
Author(s):  
Irina Dymnikova
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Space Time ◽  
Cosmological Term ◽  
De Sitter ◽  
Dark Fluid ◽  
Time Symmetry ◽  
Stress Energy ◽  
Petrov Classification ◽  
De Sitter Vacuum

The Petrov classification of stress-energy tensors provides a model-independent definition of a vacuum by the algebraic structure of its stress-energy tensor and implies the existence of vacua whose symmetry is reduced as compared with the maximally symmetric de Sitter vacuum associated with the Einstein cosmological term. This allows to describe a vacuum in general setting by dynamical vacuum dark fluid, presented by a variable cosmological term with the reduced symmetry which makes vacuum dark fluid essentially anisotropic and allows it to be evolving and clustering. The relevant regular solutions to the Einstein equations describe regular cosmological models with time-evolving and spatially inhomogeneous vacuum dark energy, and compact vacuum objects generically related to a dark energy through the de Sitter vacuum interior: regular black holes, their remnants and self-gravitating vacuum solitons — which can be responsible for observational effects typically related to a dark matter. The mass of objects with de Sitter interior is generically related to vacuum dark energy and to breaking of space-time symmetry.

scholarly journals Modified holographic energy density-driven inflation and some cosmological outcomes

2020 ◽  
Vol 17 (05) ◽  
pp. 2050066
Author(s):  
Gargee Chakraborty ◽  
Surajit Chattopadhyay
Keyword(s):  
Dark Energy ◽  
Energy Density ◽  
Bulk Viscosity ◽  
Holographic Dark Energy ◽  
State Parameter ◽  
Late Time ◽  
Effective Equation ◽  
Inflationary Scenario ◽  
Acceleration Of The Universe ◽  
The Universe

Motivated by the work of Nojiri et al. [S. Nojiri, S. D. Odintsov and E. N. Saridakis, Holographic inflation, Phys. Lett. B 797 (2019) 134829], this study reports a model of inflation under the consideration that the inflationary regime is originated by a type of holographic energy density. The infrared cutoff has been selected based on the modified holographic model that is a particular case of Nojiri–Odintsov holographic dark energy [S. Nojiri and S. D. Odintsov, Unifying phantom inflation with late-time acceleration: Scalar phantom–non-phantom transition model and generalized holographic dark energy, Gen. Relativ. Gravit. 38 (2006) 1285] that unifies phantom inflation with the acceleration of the universe on late time. On getting an analytical solution for Hubble parameter we considered the presence of bulk viscosity and the effective equation of state parameter appeared to be consistent with inflationary scenario with some constraints. It has also being observed that in the inflationary scenario the contribution of bulk viscosity is not of much significance and its influence is increasing with the evolution of the universe. Inflationary observables have been computed for the model and the slow-roll parameters have been computed. Finally, it has been observed that the trajectories in [Formula: see text] are compatible with the observational bound found by Planck. It has been concluded that the tensor to scalar ratio for this model can explain the primordial fluctuation in the early universe as well.

scholarly journals A 5D holographic dark energy in DGP-BRANE cosmology

2013 ◽  
Vol 349 (2) ◽  
pp. 961-966 ◽  
Author(s):  
H. Farajollahi ◽  
A. Ravanpak
Keyword(s):  
Dark Energy ◽  
Holographic Dark Energy ◽  
Brane Cosmology

Dark energy and viscous cosmology with variable G and Λ in an anisotropic background

2013 ◽  
Vol 91 (2) ◽  
pp. 153-157 ◽  
Author(s):  
V. Fayaz ◽  
M.R. Setare ◽  
H. Hossienkhani
Keyword(s):  
Dark Energy ◽  
Power Law ◽  
Bulk Viscosity ◽  
Deceleration Parameter ◽  
Chaplygin Gas ◽  
Density Parameter ◽  
Type I ◽  
De Sitter ◽  
Variable G And Λ ◽  
Variable G

The general Bianchi type I with dark energy in the form of standard and modified Chaplygin gas with variable G and Λ and bulk viscosity have been investigated. The de Sitter, power-law and general exponential solutions are assumed for the scale factor in each spatial direction and the corresponding cosmological models are reconstructed. Moreover, for the general exponential solutions, from which the de Sitter and power-law solutions may be obtained, we obtain models that reproduce the early universe, assumed as the inflation, and the late time accelerated expanding universe, that which yields a constant value for the deceleration parameter. We reconstruct bulk viscosity, ξ, gravitational parameter, G, cosmological term, Λ, density parameter, Ω, cosmological constant density parameter, ΩΛ, and deceleration parameter, q, for different equations of state. In the large time limit the model describes an accelerating universe wherein the effective negative pressure induced by Chaplygin gas and bulk viscous pressure are driving the acceleration.

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