The effects of dark energy on the early Universe with radiation and an ad hoc potential

2022 ◽  
Vol 137 (1) ◽  
Author(s):  
G. A. Monerat ◽  
F. G. Alvarenga ◽  
S. V. B. Gonçalves ◽  
G. Oliveira-Neto ◽  
C. G. M. Santos ◽  
...  
Keyword(s):  
Dark Energy ◽  
Early Universe ◽  
Ad Hoc

Using Lorentz Violation for Early Universe GW Generation Due to Black Hole Destruction in the Early Universe as by Freeze

2021 ◽  
Author(s):  
Andrew W Beckwith
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Energy ◽  
Early Universe ◽  
Physical Mechanism ◽  
Lorentz Violation ◽  
Graviton Mass ◽  
Work Done ◽  
Momentum Relation

We are using information from a paper deriving a Lorentz-violating energy-momentum relation entailing an exact mo_mentum cutof as stated by G. Salesi . Salesi in his work allegedly defines Pre Planckian physics, whereas we restrict our given application to GW generation and DE formation in the first 10^-39s to 10^-33s or so seconds in the early universe. This procedure is inacted due to an earlier work whereas referees exhibited puzzlement as to the physical mechanism for release of Gravitons in the very early universe. The calculation is meant to be complementary to work done in the Book “Dark Energy” by M. Li, X-D. Li, and Y. Wang, and also a calculation for Black hole destruction as outlined by Karen Freeze, et. al. The GW generation will be when there is sufficient early universe density so as to break apart Relic Black holes but we claim that this destruction is directly linked to a Lorentz violating energy-momentum G. Salesi derived, which we adopt, with a mass m added in the G. Salesi energy momentum results proportional to a tiny graviton mass, times the number of gravitons in the first 10^-43 seconds

scholarly journals Dark Energy as a Cosmological Consequence of Existence of the Dirac Scalar Field in Nature

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
O. V. Babourova ◽  
B. N. Frolov
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Cosmological Constant ◽  
Early Universe ◽  
Large Time ◽  
Field Equations ◽  
Conformal Theory ◽  
Effective Cosmological Constant ◽  
Theory Of Gravitation ◽  
Cosmological Consequence

The solution of the field equations of the conformal theory of gravitation with Dirac scalar field in Cartan-Weyl spacetime at the very early Universe is obtained. In this theory dark energy (described by an effective cosmological constant) is a function of the Dirac scalar field β. This solution describes the exponential decreasing of β at the inflation stage and has a limit to a constant value of the dark energy at large time. This can give a way to solving the fundamental cosmological constant problem as a consequence of the fields dynamics in the early 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.

scholarly journals THEORETICAL ASPECTS OF QUINTOM MODELS

2010 ◽  
Vol 25 (11n12) ◽  
pp. 909-921 ◽  
Author(s):  
TAOTAO QIU
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Cosmological Constant ◽  
Early Universe ◽  
Dark Energy Model ◽  
Phenomenological Study ◽  
Energy Model

Quintom models, with its Equation of State being able to cross the cosmological constant boundary w = -1, turns out to be attractive for phenomenological study. It can not only be applicable for dark energy model for current universe, but also lead to a bounce scenario in the early universe.

Gamma-ray bursts and cosmology

2007 ◽  
Vol 365 (1854) ◽  
pp. 1363-1376 ◽  
Author(s):  
D.Q Lamb
Keyword(s):  
Dark Energy ◽  
Early Universe ◽  
Gamma Ray ◽  
High Redshift ◽  
Gamma Ray Bursts ◽  
Current Status ◽  
Scientific Results ◽  
Short Grbs ◽  
Very High

I review the current status of the use of gamma-ray bursts (GRBs) as probes of the early Universe and cosmology. I describe the promise of long GRBs as probes of the high redshift ( z >4) and very high redshift ( z >5) Universe, and several key scientific results that have come from observations made possible by accurate, rapid localizations of these bursts by Swift. I then estimate the fraction of long GRBs that lie at very high redshifts and discuss ways in which it may be possible to rapidly identify—and therefore study—a larger number of these bursts. Finally, I discuss the ways in which both long and short GRBs can be made ‘standard candles’ and used to constrain the properties of dark energy.

THE ORDER PARAMETER FIELD FOR COSMIC STRING, INFLATION AND DARK ENERGY

2003 ◽  
Vol 18 (36) ◽  
pp. 2587-2597 ◽  
Author(s):  
PENG-MING ZHANG ◽  
YI-SHI DUAN ◽  
LI-MING CAO
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Early Universe ◽  
Cosmic String ◽  
Order Parameter ◽  
Cosmic Strings ◽  
Complex Scalar ◽  
Parameter Field ◽  
Complex Scalar Field

We present a whole frame for the cosmic strings, inflation and dark energy with the complex scalar field which can be regarded as the order parameter of our universe. One can find that the comic strings emerge in the zeros of the complex scalar field in the early universe. And with the evolution of complex scalar field, inflation and dark energy can be understood in this frame.

scholarly journals Origin of Universe accelerated expansion and prediction of the right deceleration parameter

2019 ◽  
Author(s):  
Paolo Di Sia
Keyword(s):  
Dark Energy ◽  
Deceleration Parameter ◽  
Ad Hoc ◽  
Accelerated Expansion ◽  
Dense Layer ◽  
De Sitter ◽  
Dark Energy Density ◽  
Particle Velocities ◽  
De Sitter Universe ◽  
The Right

The filament (f) theory implies initial isotropic particle-velocities with uniform value-distribution between zero and the speed of light c. That leads to a universe boundary coinciding with the events horizon of its centre. The very dense layer of particles and antiparticles expanding with almost c observed at retarded times attracts the internal particles thus implying for them an accelerated expansion. There is no need for an "ad hoc" dark energy implying repulsion. The predicted negative deceleration parameter q corresponds to a dark energy density 95.5 % of the critical value. If the red-shift of far galaxies was due to the only Doppler-Fizeau effect, the standard value 73 % is obtained. The past and future q is predicted. The q value was a negative maximum just after the primordial annihilation of the particles with the antiparticles and will vanish at about 3TH (where TH denotes the Hubble time) after the present time t. For t larger than 3TH, it will be positive, tending to 1/2, typical of the Einstein-De Sitter universe.

scholarly journals LITTLE RIP AND PSEUDO RIP PHENOMENA FROM COUPLED DARK ENERGY

2013 ◽  
Vol 28 (37) ◽  
pp. 1350172 ◽  
Author(s):  
I. BREVIK ◽  
A. V. TIMOSHKIN ◽  
Y. RABOCHAYA
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Equation Of State ◽  
Early Universe ◽  
Equations Of State ◽  
Cosmological Models ◽  
Ideal Fluids ◽  
Interaction Term ◽  
Gravitational Equations

We consider Little Rip (LR) and Pseudo Rip (PR) cosmological models with two interacting ideal fluids, corresponding to dark energy and dark matter. The interaction between the dark energy and the dark matter fluid components is described in terms of the parameters in the equations of state for the LR and PR universes. In contrast to a model containing only a pure dark energy, the presence of the interaction term between the fluid components in the gravitational equations leads to a modification of the equation of state parameters. The properties of the early universe in this formalism are pointed out.

scholarly journals No Need for Dark-Matter, Dark-Energy or Inflation, Once Ordinary Matter is Properly Represented?

2018 ◽  
Author(s):  
Yehonatan Knoll
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Large Scale ◽  
Ad Hoc ◽  
Classical Electrodynamics ◽  
Spontaneous Breaking ◽  
Metric Tensor ◽  
Ordinary Matter ◽  
Scale Covariance ◽  
Self Force

In a recent Foundations of Physics paper [5] by the current author it was shown that, when the self force problem of classical electrodynamics is properly solved, it becomes a plausible ontology underlying the statistical description of quantum mechanics. In the current paper we extend this result, showing that ordinary matter, thus represented, possibly suffices in explaining the outstanding observations currently requiring for this task the contrived notions of dark-matter, dark-energy and inflation. The single mandatory `fix' to classical electrodynamics, demystifying both very small and very large scale physics, should be contrasted with other ad hoc solutions to either problems. Instrumental to our cosmological model is scale covariance (and `spontaneous breaking' thereof), a formal symmetry of classical electrodynamics treated on equal footing with its Poincare covariance, which is incompatible with the (absolute) metrical attributes of the GR metric tensor.

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