scholarly journals Could Information Energy resolve Hubble Tension?

2021 ◽  
Author(s):  
Michael Paul Gough
Keyword(s):  
Dark Energy ◽  
Cosmological Constant ◽  
State Parameter ◽  
Total Entropy ◽  
Energy Contribution ◽  
Constant Energy ◽  
Entropy Information ◽  
Equation Of State Parameter ◽  
Constant Energy Density ◽  
Information Energy

Stellar heated gas and dust has a universe total entropy/information content of ~10^86 bits. At typical temperatures ~10^7 the equivalent N kB T ln(2) information energy ~10^70 J is comparable to the mc2 of the universe’s ~10^53 kg of baryons. At low red-shifts, z<1.35 this dark energy contribution provides a near constant energy density, with an equation of state parameter, w=-1.03±0.05, effectively emulating a cosmological constant to within 1.8% in Hubble parameter, H(a). Earlier, z>1.35, the information energy contribution was phantom, w=-1.82±0.08. This dark energy differs from the cosmological constant by △w0= -0.03±0.05 and △wa= -0.79±0.08, sufficient to account for the value of the ‘Hubble Tension’ between early and late universe H0 values. An information energy model will fit most observations as well as Ʌ, and also resolve Hubble tension and cosmological coincidence problems. Furthermore, information energy could also account for many effects previously attributed to dark matter.

scholarly journals BOUNCING MODELS WITH A COSMOLOGICAL CONSTANT

2011 ◽  
Vol 03 ◽  
pp. 294-302
Author(s):  
NELSON PINTO-NETO ◽  
BEATRIZ B. SIFFERT ◽  
RODRIGO MAIER ◽  
STELLA PEREIRA
Keyword(s):  
Dark Energy ◽  
Cosmological Constant ◽  
Initial Conditions ◽  
State Parameter ◽  
Vacuum State ◽  
Cosmological Perturbations ◽  
Scale Invariant ◽  
Stiff Matter ◽  
Equation Of State Parameter ◽  
Contracting Phase

Most bouncing models contain a contracting phase from a very large and rarefied state, where dark energy might have had an important role. If this is that case, the presence of dark energy can modify the initial conditions and evolution of cosmological perturbations, changing the known results already obtained in the literature concerning their amplitude and spectrum. In this work, we assume the simplest and most appealing candidate for dark energy, the cosmological constant, and study its influence on the evolution of cosmological perturbations during the contracting phase of a bouncing model, containing also a perfect fluid with constant equation of state parameter w. We show that, due to the vacuum state choice we have to make when a cosmological constant is present, the spectrum of the perturbations are substantially altered. We conclude that, in this case, the presence of a stiff matter fluid in the contracting phase is needed in order to have a scale invariant spectrum of perturbations in the expanding phase.

scholarly journals Information Energy Mimics Ʌ and CDM

2019 ◽  
Author(s):  
Michael Paul Gough
Keyword(s):  
Dark Matter ◽  
Cosmological Constant ◽  
Mass Density ◽  
Energy Contribution ◽  
Coincidence Problem ◽  
Galaxy Surveys ◽  
Energy Equivalence ◽  
Constant Energy Density ◽  
Information Energy ◽  
The Universe

Stellar heated gas and dust makes a significant entropic/information energy contribution to the universe. At temperatures ~107 the ~1086 bits are equivalent to ~1070J, equivalent to the energy equivalence of the universe’s ~1053 kg ordinary baryon matter. A survey of stellar mass density measurements shows this dark energy contribution has a constant energy density that effectively mimics a cosmological constant over the redshift range z<1.35. The measurable difference between this information energy and a true cosmological constant is small, with a maximum difference of <2% in Hubble parameter at z~2. As information energy is significant and co-located with hot baryons it produces gravitational effects that resemble dark matter. Information energy is shown to be consistent with the dark matter effects observed in clusters of colliding galaxies (e.g. Bullet Cluster), with dark matter location specified by baryon location and strongest in regions of highest luminosity / temperature. The dark matter fraction measured in galaxy surveys more closely fits an information energy explanation than the fraction expected in the standard ɅCDM model. Information energy provides a solution to the cosmological coincidence problem and also would allow the cosmological constant to take the preferred zero value.

scholarly journals Transient dark energy, cosmological constant boundary crossing and dark energy w(z) data fits

2019 ◽  
Vol 28 (03) ◽  
pp. 1950045 ◽  
Author(s):  
Dalibor Perković ◽  
Hrvoje Štefančić
Keyword(s):  
Dark Energy ◽  
Cosmological Constant ◽  
State Parameter ◽  
Specific Model ◽  
Boundary Crossing ◽  
Transient Phenomenon ◽  
Model Dynamics ◽  
Equation Of State Parameter ◽  
Specific Parameter ◽  
Energy Formula

The formalism of dark energy based on modeling speed of sound as a function of equation-of-state parameter is elaborated. A specific model which allows detailed study of cosmological constant boundary crossing is introduced and analytical solutions for the model dynamics are obtained. It is shown how in specific parameter regimes dark energy can be a transient phenomenon. It is further demonstrated how the model reproduces specific features of recent fits of dark energy [Formula: see text] to observational data.

scholarly journals Beyond ɅCDM: A Viable Alternative?

2017 ◽  
Author(s):  
Paul Gough
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Equation Of State ◽  
State Parameter ◽  
Phenomenological Approach ◽  
Coincidence Problem ◽  
Accelerating Expansion ◽  
Sufficient Energy ◽  
Equation Of State Parameter ◽  
Information Energy

We are encouraged to look beyond ɅCDM as there are no satisfactory explanations for either dark energy or dark matter. A data centred phenomenological approach supports an explanation where dark energy is Holographic Dark Information Energy, HDIE. HDIE explains many effects attributed separately to Ʌ and CDM. HDIE mimics Ʌ with sufficient energy and an equation of state parameter, w= -1.03±0.05 at redshifts z<1.35 to account for accelerating expansion. HDIE is clumped around galaxies at densities that distort space-time, explaining many CDM attributed effects. The present ratio of HDIE/baryons ~2.15, required for the observed expansion history, is equivalent to a dark matter fraction ~68%, consistent with many galaxies. The HDIE/baryon model is based largely on proven physics, provides a common explanation for dark energy and dark matter, and solves the cosmological coincidence problem. At earlier times, z > ~1.35, HDIE was phantom, w = -1.82±0.08, enabling the model to be falsified. HDIE fits Planck dark energy wo-wa plots at least as well as Ʌ, and is consistent with other results that suggest dark energy was phantom at earlier times. A new w-parameterisation is proposed, as the usual CPL parameterisation is biased and unsuitable for distinguishing between HDIE/baryon and ɅCDM models.

FRW viscous fluid cosmological model with time-dependent inhomogeneous equation of state

2017 ◽  
Vol 15 (01) ◽  
pp. 1830001 ◽  
Author(s):  
G. S. Khadekar ◽  
Deepti Raut
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Quadratic Form ◽  
State Parameter ◽  
The Other ◽  
Time Dependent ◽  
Inhomogeneous Equation ◽  
Field Equations ◽  
Equation Of State Parameter ◽  
Viscous Models

In this paper, we present two viscous models of non-perfect fluid by avoiding the introduction of exotic dark energy. We consider the first model in terms of deceleration parameter [Formula: see text] has a viscosity of the form [Formula: see text] and the other model in quadratic form of [Formula: see text] of the type [Formula: see text]. In this framework we find the solutions of field equations by using inhomogeneous equation of state of form [Formula: see text] with equation of state parameter [Formula: see text] is constant and [Formula: see text].

scholarly journals Cosmological Implications of the Generalized Entropy Based Holographic Dark Energy Models in Dynamical Chern-Simons Modified Gravity

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
M. Younas ◽  
Abdul Jawad ◽  
Saba Qummer ◽  
H. Moradpour ◽  
Shamaila Rani
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Modified Gravity ◽  
Dark Energy Model ◽  
State Parameter ◽  
Energy Model ◽  
Evolutionary Equation ◽  
Energy Models ◽  
Equation Of State Parameter ◽  
Chern Simons

Recently, Tsallis, Rényi, and Sharma-Mittal entropies have widely been used to study the gravitational and cosmological setups. We consider a flat FRW universe with linear interaction between dark energy and dark matter. We discuss the dark energy models using Tsallis, Rényi, and Sharma-Mittal entropies in the framework of Chern-Simons modified gravity. We explore various cosmological parameters (equation of state parameter, squared sound of speed ) and cosmological plane (ωd-ωd′, where ωd′ is the evolutionary equation of state parameter). It is observed that the equation of state parameter gives quintessence-like nature of the universe in most of the cases. Also, the squared speed of sound shows stability of Tsallis and Rényi dark energy model but unstable behavior for Sharma-Mittal dark energy model. The ωd-ωd′ plane represents the thawing region for all dark energy models.

scholarly journals BRANE–BULK ENERGY EXCHANGE AND AGEGRAPHIC DARK ENERGY

2010 ◽  
Vol 19 (03) ◽  
pp. 305-316 ◽  
Author(s):  
AHMAD SHEYKHI
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Equation Of State ◽  
Normal State ◽  
Energy Exchange ◽  
State Parameter ◽  
Effective Equation ◽  
Agegraphic Dark Energy ◽  
Equation Of State Parameter ◽  
Bulk Energy

We consider the agegraphic models of dark energy in a braneworld scenario with brane–bulk energy exchange. We assume that the adiabatic equation for the dark matter is satisfied while it is violated for the agegraphic dark energy due to the energy exchange between the brane and the bulk. Our study shows that with the brane–bulk interaction, the equation of state parameter of agegraphic dark energy on the brane, wD, can have a transition from the normal state, where wD > -1, to the phantom regime, where wD < -1, while the effective equation of state for dark energy always satisfies [Formula: see text].

Viability of specific reconstructed f(T,𝒯 ) models

2019 ◽  
Vol 34 (30) ◽  
pp. 1950184
Author(s):  
M. Umair Shahzad ◽  
Nadeem Azhar ◽  
Abdul Jawad ◽  
Shamaila Rani
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Dark Energy Model ◽  
State Parameter ◽  
Pilgrim Dark Energy ◽  
Ghost Dark Energy ◽  
Energy Models ◽  
Equation Of State Parameter ◽  
Hubble Horizon ◽  
The Universe

The reconstruction scenario of well-established dark energy models such as pilgrim dark energy model and generalized ghost dark energy with Hubble horizon and [Formula: see text] models is being considered. We have established [Formula: see text] models and analyzed their viability through equation of state parameter and [Formula: see text] (where prime denotes derivative with respect to [Formula: see text]) plane. The equation of state parameter evolutes the universe in three different phases such as quintessence, vacuum and phantom. However, the [Formula: see text] plane also describes the thawing as well as freezing region of the universe. The recent observational data also favor our results.

scholarly journals GENERALIZED MODEL FOR Λ DARK ENERGY

2009 ◽  
Vol 18 (03) ◽  
pp. 389-396 ◽  
Author(s):  
UTPAL MUKHOPADHYAY ◽  
P. C. RAY ◽  
SAIBAL RAY ◽  
S. B. DUTTA CHOUDHURY
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Cosmological Model ◽  
A Priori ◽  
State Parameter ◽  
Spherically Symmetric ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Equation Of State Parameter ◽  
Two Fluid

Einstein field equations under spherically symmetric space–times are considered here in connection with dark energy investigation. A set of solutions is obtained for a kinematic Λ model, viz. [Formula: see text], without assuming any a priori value for the curvature constant and the equation-of-state parameter ω. Some interesting results, such as the nature of cosmic density Ω and deceleration parameter q, have been obtained with the consideration of two-fluid structure instead of the usual unifluid cosmological model.

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