scholarly journals Viscous fluid holographic bounce

2019 ◽  
Vol 17 (02) ◽  
pp. 2050023 ◽  
Author(s):  
I. Brevik ◽  
A. V. Timoshkin

We investigate bounce cosmological models in the presence of a viscous fluid, making use of generalized holographic cutoffs introduced by Nojiri and Odintsov [Covariant generalized holographic dark energy and accelerated universe, Eur. Phys. J. C 77 (2017) 528, arXiv:1703.06372 [hep-th]]. We consider both an exponential, a power-law, and a double exponential form for the scale factor. By use of these models, we calculate expressions for infrared cutoffs analytically, such that they correspond to the particle horizon at the bounce. Finally, we derive the energy conservation equation, from the holographic point of view. In that way, the relationship between the viscous fluid bounce and the holographic bounce is demonstrated.

2014 ◽  
Vol 29 (15) ◽  
pp. 1450078 ◽  
Author(s):  
I. Brevik ◽  
V. V. Obukhov ◽  
A. V. Timoshkin

We investigate cosmological models with a linear inhomogeneous time-dependent equation-of-state (EoS) for the dark energy, coupled with dark matter, leading to a bounce cosmology. Equivalent descriptions in terms of the EoS parameters for an exponential, a power-law, or a double exponential form of the scale factor a is obtained. The stability of the solutions is explored, by considering small perturbations around the critical points for the bounce in the early and in the late-time universe.


Author(s):  
I. Brevik ◽  
A. V. Timoshkin

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.


2009 ◽  
Vol 24 (22) ◽  
pp. 1785-1792 ◽  
Author(s):  
B. NAYAK ◽  
L. P. SINGH

The present-day accelerated expansion of the universe is naturally addressed within the Brans–Dicke theory just by using holographic dark energy model with inverse of Hubble scale as IR cutoff and power law temporal behavior of scale factor. It is also concluded that if the universe continues to expand, then one day it might be completely filled with dark energy.


2022 ◽  
Vol 21 (12) ◽  
pp. 317
Author(s):  
Gargee Chakraborty ◽  
Surajit Chattopadhyay ◽  
Ertan Güdekli

Abstract The work reported in this paper demonstrates the cosmology of f(Q) gravity and the reconstruction of various associated parameters with different versions of holographic dark energy with generalized cut-offs, where Q = 6 H 2. The Universe is considered to be filled with viscous fluid characterized by a viscous pressure Π = – 3 H ξ, where ξ = ξ 0 + ξ 1 H + ξ 2 ( H ˙ + H 2 ) and H is the Hubble parameter. Considering the power law form of expansion, we have derived the expression of f(Q) under a non-viscous holographic framework and it is then extended to viscous cosmological settings with extended generalized holographic Ricci dark energy. The forms of f(Q) for both the cases are found to be monotonically increasing functions of Q. In the viscous holographic framework, f(Q) is reconstructed as a function of cosmic time t and is found to stay at a positive level with Nojiri-Odintsov cut-off. In these cosmological settings, the slow roll parameters are computed and a scope of exit from inflation and quasi-exponential expansion are found to be available. Finally, it is observed that warm inflationary expansion can be obtained from this model.


2013 ◽  
Vol 344 (2) ◽  
pp. 489-494 ◽  
Author(s):  
Abdul Jawad ◽  
Antonio Pasqua ◽  
Surajit Chattopadhyay

Author(s):  
Rahul Ghosh ◽  
Ujjal Debnath ◽  
Shuvendu Chakraborty

Modified gravity models are popular among cosmologists, as they can describe the cosmological evolution quite efficiently. Reconstruction of newly introduced [Formula: see text] gravity, with the help of ordinary, power-law entropy corrected and logarithmic entropy-corrected versions of Holographic dark energy (HDE) and Pilgrim dark energy (PDE) models have been studied in this work. For such reconstruction, we have considered the power-law scale factor [Formula: see text]. Further, the classical stabilities (the squared speed of sound method) of such reconstructions and their implications on the nature of the equation of state (EoS) parameters and deceleration parameter with respect to red-shift have also been examined. Finally, we have computed the age of the universe for reconstructed models.


2015 ◽  
Vol 93 (4) ◽  
pp. 475-480 ◽  
Author(s):  
Bharat Borah ◽  
M. Ansari

The purpose of this paper is to study power-law entropy-corrected holographic dark energy (PLECHDE) in the framework of Brans–Dicke cosmology with Granda–Oliveros (G-O) IR-cutoff. Considering the interacting and non-interacting scenario of PLECHDE with dark matter, we investigate the cosmological implications of this model in detail. We obtain the equation of state parameter, deceleration parameter, and evolution of dark energy density to explain expansion of the universe. We also determine these parameters for Ricci scale. We extend our study of the power-law entropy-corrected agegraphic dark energy model and calculate some cosmological parameters. Further, we show that the results that we calculate have good compatibility with previous work and matches it in the limiting case. Finally, we find a cosmological application of our work by evaluating the equation of state of dark energy for low red-shift.


2019 ◽  
Vol 35 (02) ◽  
pp. 1950355
Author(s):  
Claudio Corianò ◽  
Paul H. Frampton

The holographic principle provides a deep insight into quantum gravity and resolves the fine-tuning crisis concerning the cosmological constant. Holographic dark energy introduces new ultraviolet (UV) and infrared (IR) cutoffs into quantum gravity which are necessarily strongly related. The equation of state for dark energy [Formula: see text] is discussed from the holographic point of view. The phantom option of [Formula: see text] is resurrected, as in an earlier cyclic cosmology. Such a cyclic model can, however, equally use the cosmological constant with [Formula: see text].


Sign in / Sign up

Export Citation Format

Share Document