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.

Ω0 Concordance

2005 ◽  
Vol 201 ◽  
pp. 271-281
Author(s):  
Masataka. Fukugita
Keyword(s):  
Dark Matter ◽  
Cosmological Constant ◽  
Structure Formation ◽  
Cold Dark Matter ◽  
Mass Density ◽  
Hubble Constant ◽  
Density Parameter ◽  
Microwave Background ◽  
The Hierarchical Structure ◽  
The Universe

The determinations of the mass density parameter Ω0 are examined with a particular emphasis given to the new cosmic microwave background (CMB) experiments. It is shown that the Ω0 and the Hubble constant H0 from CMB are quite consistent with those from other observations with the aid of the hierarchical structure formation models based on cold dark matter dominance with the cosmological constant that makes the universe flat. The concordance value of Ω0 is 0.25-0.45.

COUPLED QUINTESSENCE AND THE COINCIDENCE PROBLEM

2003 ◽  
Vol 18 (12) ◽  
pp. 831-842 ◽  
Author(s):  
G. MANGANO ◽  
G. MIELE ◽  
V. PETTORINO
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Energy Density ◽  
Cosmological Constant ◽  
Phenomenological Model ◽  
Coincidence Problem ◽  
Strongly Coupled ◽  
Coexisting Phases ◽  
The Universe ◽  
Universe Evolution

We consider a model of interacting cosmological constant/quintessence, where dark matter and dark energy behave as, respectively, two coexisting phases of a fluid, a thermally excited Bose component and a condensate, respectively. In a simple phenomenological model for the dark components interaction we find that their energy density evolution is strongly coupled during the universe evolution. This feature provides a possible way out for the coincidence problem affecting many quintessence models.

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 INTERACTION BETWEEN DARK ENERGY AND DARK MATTER: OBSERVATIONAL CONSTRAINTS FROM OHD, BAO, CMB AND SNe Ia

2013 ◽  
Vol 22 (14) ◽  
pp. 1350082 ◽  
Author(s):  
SHUO CAO ◽  
NAN LIANG
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Observational Constraints ◽  
Coincidence Problem ◽  
Cosmological Constraints ◽  
Coincidence Index ◽  
Acceleration Of The Universe ◽  
Interaction Term ◽  
Negative Coupling ◽  
The Universe

In order to test if there is energy transfer between dark energy (DE) and dark matter (DM), we investigate cosmological constraints on two forms of nontrivial interaction between the DM sector and the sector responsible for the acceleration of the universe, in light of the newly revised observations including OHD, CMB, BAO and SNe Ia. More precisely, we find the same tendencies for both phenomenological forms of the interaction term Q = 3γHρ, i.e. the parameter γ to be a small number, |γ| ≈ 10-2. However, concerning the sign of the interaction parameter, we observe that γ > 0 when the interaction between dark sectors is proportional to the energy density of dust matter, whereas the negative coupling (γ < 0) is preferred by observations when the interaction term is proportional to DE density. We further discuss two possible explanations to this incompatibility and apply a quantitative criteria to judge the severity of the coincidence problem. Results suggest that the γm IDE model with a positive coupling may alleviate the coincidence problem, since its coincidence index C is smaller than that for the γd IDE model, the interacting quintessence and phantom models by four orders of magnitude.

scholarly journals Cosmological constant, matter, cosmic inflation and coincidence

2020 ◽  
Vol 35 (15) ◽  
pp. 2050123
Author(s):  
She-Sheng Xue
Keyword(s):  
Dark Matter ◽  
Acoustic Wave ◽  
Cosmological Constant ◽  
Einstein Equation ◽  
Large Scale ◽  
Particle Production ◽  
Cosmological Term ◽  
Coincidence Problem ◽  
Cosmic Inflation ◽  
Cosmic Coincidence Problem

We present a possible understanding to the issues of cosmological constant, inflation, dark matter and coincidence problems based only on the Einstein equation and Hawking particle production. The inflation appears and results agree to observations. The CMB large-scale anomaly can be explained and the dark-matter acoustic wave is speculated. The entropy and reheating are discussed. The cosmological term [Formula: see text] tracks down the matter [Formula: see text] until the radiation-matter equilibrium, then slowly varies, thus the cosmic coincidence problem can be avoided. The relation between [Formula: see text] and [Formula: see text] is shown and can be examined at large redshifts.

scholarly journals CAN BRANS–DICKE SCALAR FIELD ACCOUNT FOR DARK ENERGY AND DARK MATTER?

2006 ◽  
Vol 21 (15) ◽  
pp. 1241-1248 ◽  
Author(s):  
M. ARIK ◽  
M. C. ÇALIK
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Energy Density ◽  
Late Time ◽  
Energy Contribution ◽  
Time Solution ◽  
The Universe

By using a linearized non-vacuum late time solution in Brans–Dicke cosmology, we account for the 75% dark energy contribution but not for approximately 23% dark matter contribution to the present day energy density of the universe.

scholarly journals ACCELERATION AND DECELERATION IN THE CURVATURE-INDUCED PHANTOM MODEL OF THE LATE AND FUTURE UNIVERSE: COSMIC COLLAPSE AND ITS QUANTUM ESCAPE

2009 ◽  
Vol 18 (05) ◽  
pp. 865-887
Author(s):  
S. K. SRIVASTAVA ◽  
J. DUTTA
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Quantum Gravity ◽  
Cosmological Constant ◽  
Early Universe ◽  
High Energy ◽  
High Energy Density ◽  
Energy Models ◽  
Acceleration And Deceleration ◽  
The Universe

In this paper, the cosmology of the late and future universe is obtained from f(R) gravity with nonlinear curvature terms R2 and R3 (R is the Ricci scalar curvature). It is different from f(R) dark energy models where nonlinear curvature terms are taken as a gravitational alternative to dark energy. In the present model, neither linear nor nonlinear curvature terms are taken as dark energy. Rather, dark energy terms are induced by curvature terms and appear in the Friedmann equation derived from f(R) gravitational equations. This approach has an advantage over f(R) dark energy models in three ways: (i) results are consistent with WMAP observations, (ii) dark matter is produced from the gravitational sector and (iii) the universe expands as ~ t2/3 during dominance of the curvature-induced dark matter, which is consistent with the standard cosmology. Curvature-induced dark energy mimics phantom and causes late acceleration. It is found that transition from matter-driven deceleration to acceleration takes place at the redshift 0.36 at time 0.59 t0 (t0 is the present age of the universe). Different phases of this model, including acceleration and deceleration during the phantom phase, are investigated. It is found that expansion of the universe will stop at the age of 3.87 t0 + 694.4 kyr. After this epoch, the universe will contract and collapse by the time of 336.87 t0 + 694.4 kyr. Further, it is shown that cosmic collapse obtained from classical mechanics can be avoided by making quantum gravity corrections relevant near the collapse time due to extremely high energy density and large curvature analogous to the state of the very early universe. Interestingly, the cosmological constant is also induced here; it is extremely small in the classical domain but becomes very high in the quantum domain. This result explains the largeness of the cosmological constant in the early universe due to quantum gravity effects during this era and its very low value in the present universe due to negligible quantum effect in the late universe.

Observational and astrophysical cosmology: 1980–2018

2019 ◽  
pp. 375-423
Author(s):  
Malcolm S. Longair
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cosmological Constant ◽  
Large Scale ◽  
Cosmological Parameters ◽  
Semiconductor Detectors ◽  
Empirical Knowledge ◽  
Global Geometry ◽  
The Universe ◽  
Large Scale Structure Formation

Since 1980, our empirical knowledge of the universe has advanced tremendously and precision cosmology has become a reality. These developments have been largely technology-driven, the result of increased computer power, new generations of telescopes for all wavebands, new types of semiconductor detectors, such as CCDs, and major investments by many nations in superb observing facilities. The discipline also benefitted from the influx of experimental and theoretical physicists into the cosmological arena. The accuracy and reliability of the values of the cosmological parameters has improved dramatically, many of them now being known to about 1%. The ΛCDM model provides a remarkable fit to all the observational data, demonstrating that the cosmological constant is non-zero and that the global geometry of the universe is flat. The underlying physics of galaxy and large-scale structure formation has advanced dramatically and demonstrated the key roles played by dark matter and dark energy.

scholarly journals Thermodynamical description of the ghost dark energy model

2015 ◽  
Vol 24 (07) ◽  
pp. 1550048 ◽  
Author(s):  
M. Honarvaryan ◽  
A. Sheykhi ◽  
H. Moradpour
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Dark Energy Model ◽  
State Parameter ◽  
Thermal Fluctuations ◽  
Mutual Interaction ◽  
Coincidence Problem ◽  
Ghost Dark Energy ◽  
Equation Of State Parameter ◽  
The Universe

In this paper, we point out thermodynamical description of ghost dark energy (GDE) and its generalization to the early universe. Thereinafter, we find expressions for the entropy changes of these dark energy (DE) candidates. In addition, considering thermal fluctuations, thermodynamics of the DE component interacting with a dark matter (DM) sector is addressed. We will also find the effects of considering the coincidence problem on the mutual interaction between the dark sectors, and thus the equation of state parameter of DE. Finally, we derive a relation between the mutual interaction of the dark components of the universe, accelerated with the either GDE or its generalization, and the thermodynamic fluctuations.

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