scholarly journals Application of Self-Similar Symmetry Model to Dark Energy

2018 ◽  
Author(s):  
Tomohide Sonoda
Keyword(s):  
Dark Energy ◽  
Energy Density ◽  
Vacuum Energy ◽  
Structure Constant ◽  
Fine Tuning ◽  
Theoretical Modelling ◽  
Fine Structure Constant ◽  
Vacuum Energy Density ◽  
Self Similar ◽  
The Universe

Recent observations of the dark energy density demonstrates the fine-tuning problem and challenges in theoretical modelling. In this study, we apply the self-similar symmetry (SSS) model, describing the hierarchical structure of the universe based on the Dirac large numbers hypothesis, to Einstein's cosmological term. We introduce a new similarity dimension, DB, in the SSS model. Using the DB SSS model, the cosmological constant, vacuum energy density, and Hubble parameter can be simply expressed as a function of the cosmic microwave background (CMB) temperature. We show that the initial value of the vacuum energy density at the creation of the universe is ρ0 = 1/8παf6, where αf is the fine structure constant. The results indicate that the CMB is the primary factor for the evolution of the universe, providing a unified understanding of the problems of naturalness.

scholarly journals Dark matter, dark energy and the time evolution of masses in the universe

2014 ◽  
Vol 29 (21) ◽  
pp. 1444016 ◽  
Author(s):  
Joan Solà
Keyword(s):  
Dark Energy ◽  
Vacuum Energy ◽  
Planck Scale ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Vacuum Energy Density ◽  
Electron Mass ◽  
Static Vacuum ◽  
The Masses ◽  
The Universe

The traditional "explanation" for the observed acceleration of the universe is the existence of a positive cosmological constant. However, this can hardly be a truly convincing explanation, as an expanding universe is not expected to have a static vacuum energy density. So, it must be an approximation. This reminds us of the so-called fundamental "constants" of nature. Recent and past measurements of the fine structure constant and of the proton–electron mass ratio suggest that basic quantities of the standard model, such as the QCD scale parameter, Λ QCD , might not be conserved in the course of the cosmological evolution. The masses of the nucleons and of the atomic nuclei would be time-evolving. This can be consistent with General Relativity provided the vacuum energy itself is a dynamical quantity. Another framework realizing this possibility is QHD (Quantum Haplodynamics), a fundamental theory of bound states. If one assumes that its running couplings unify at the Planck scale and that such scale changes slowly with cosmic time, the masses of the nucleons and of the DM particles, including the cosmological term, will evolve with time. This could explain the dark energy of the universe.

scholarly journals Do we come from a quantum anomaly?

2019 ◽  
Vol 28 (14) ◽  
pp. 1944002 ◽  
Author(s):  
Spyros Basilakos ◽  
Nick E. Mavromatos ◽  
Joan Solà Peracaula
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Energy Density ◽  
Hubble Parameter ◽  
Vacuum Energy ◽  
Vacuum Energy Density ◽  
Quantum Anomaly ◽  
Inflationary Phase ◽  
Axion Field ◽  
The Universe

We present a string-based picture of the cosmological evolution in which (CP-violating) gravitational anomalies acting during the inflationary phase of the universe cause the vacuum energy density to “run” with the effective Hubble parameter squared, [Formula: see text], thanks to the axion field of the bosonic string multiplet. This leads to baryogenesis through leptogenesis with massive right-handed neutrinos. The generation of chiral matter after inflation helps in cancelling the anomalies in the observable radiation- and matter-dominated eras. The present era inherits the same “running vacuum” structure triggered during the inflationary time by the axion field. The current dark energy is thus predicted to be mildly dynamical, and dark matter should be made of axions. Paraphrasing Carl Sagan [ https://www.goodreads.com/author/quotes/10538.Carl_Sagan .]: we are all anomalously made from starstuff.

scholarly journals On the electrodynamics of moving particles in a quasi flat spacetime with Lorentz violation and its cosmological implications

2016 ◽  
Vol 25 (10) ◽  
pp. 1650096 ◽  
Author(s):  
Cláudio Nassif Cruz
Keyword(s):  
Electromagnetic Field ◽  
Energy Density ◽  
Gravitational Potential ◽  
Vacuum Energy ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Vacuum Energy Density ◽  
Gravitational Fields ◽  
Flat Spacetime ◽  
Minimum Speed

This research aims to develop a new approach towards a consistent coupling of electromagnetic and gravitational fields, by using an electron that couples with a weak gravitational potential by means of its electromagnetic field. To accomplish this, we must first build a new model which provides the electromagnetic nature of both the mass and the energy of the electron, and which is implemented with the idea of [Formula: see text]-photon decay into an electron–positron pair. After this, we place the electron (or positron) in the presence of a weak gravitational potential given in the intergalactic medium, so that its electromagnetic field undergoes a very small perturbation, thus leading to a slight increase in the field’s electromagnetic energy density. This perturbation takes place by means of a tiny coupling constant [Formula: see text] because gravity is a very weak interaction compared with the electromagnetic one. Thus, we realize that [Formula: see text] is a new dimensionless universal constant, which reminds us of the fine structure constant [Formula: see text]; however, [Formula: see text] is much smaller than [Formula: see text] because [Formula: see text] takes into account gravity, i.e. [Formula: see text]. We find [Formula: see text], where [Formula: see text] is the speed of light and [Formula: see text][Formula: see text]m/s) is a universal minimum speed that represents the lowest limit of speed for any particle. Such a minimum speed, unattainable by particles, represents a preferred reference frame associated with a background field that breaks the Lorentz symmetry. The metric of the flat spacetime shall include the presence of a uniform vacuum energy density, which leads to a negative pressure at cosmological scales (cosmological anti-gravity). The tiny values of the cosmological constant and the vacuum energy density will be successfully obtained in agreement with the observational data.

scholarly journals Quantum Mechanical Explanation for Dark Energy, Cosmic Coincidence, Flatness, Age, and Size of the Universe

2019 ◽  
Vol 28 (1) ◽  
pp. 220-227 ◽  
Author(s):  
Biswaranjan Dikshit
Keyword(s):  
Dark Energy ◽  
Energy Density ◽  
Vacuum Energy ◽  
Vacuum Energy Density ◽  
Quantum Mechanical ◽  
Coincidence Problem ◽  
Astronomical Observations ◽  
The Universe ◽  
Matter Energy ◽  
Cosmic Coincidence Problem

Abstract One of the most important problems in astronomy is the cosmological constant problem in which conventional calculation of vacuum energy density using quantum mechanics leads to a value which is ~10123 times more than the vacuum energy estimated from astronomical observations of expanding universe. The cosmic coincidence problem questions why matter energy density is of the same order of magnitude as the vacuum energy density at present time. Finally, the mechanism responsible for spatial flatness is not clearly understood. In this paper, by taking the vacuum as a finite and closed quantum oscillator, we solve all of the above-mentioned problems. At first, by using the purely quantum mechanical approach, we predict that the dark energy density is c4/(GR2) = 5.27×10−10 J/m3 (where R is radius of 3-sphere of the universe) and matter energy density is c4/(2GR2) = 2.6×10−10 J/m3 which match well with astronomical observations. We also prove that dark energy has always been ~66.7% and matter energy has been ~33.3% of the total energy and thus solve the cosmic coincidence problem. Next, we show how flatness of space could be maintained since the early stage of the universe. Finally, using our model, we derive the expression for age and radius of the universe which match well with the astronomical data.

scholarly journals DARK ENERGY DENSITY IN MODELS WITH SPLIT SUPERSYMMETRY AND DEGENERATE VACUA

2012 ◽  
Vol 27 (11) ◽  
pp. 1250063 ◽  
Author(s):  
C. FROGGATT ◽  
R. NEVZOROV ◽  
H. B. NIELSEN
Keyword(s):  
Dark Energy ◽  
Energy Density ◽  
Cosmological Constant ◽  
Vacuum Energy ◽  
Susy Breaking ◽  
Vacuum Energy Density ◽  
Dark Energy Density ◽  
Hidden Sector ◽  
Split Supersymmetry ◽  
Breaking Scale

In N = 1 supergravity supersymmetric and nonsupersymmetric Minkowski vacua originating in the hidden sector can be degenerate. In the supersymmetric phase in flat Minkowski space, nonperturbative supersymmetry breakdown may take place in the observable sector, inducing a nonzero and positive vacuum energy density. Assuming that such a supersymmetric phase and the phase in which we live are degenerate, we estimate the value of the cosmological constant. We argue that the observed value of the dark energy density can be reproduced in the split SUSY scenario of SUSY breaking if the SUSY breaking scale is of order of 1010 GeV.

scholarly journals Dynamical dark energy with a constant vacuum energy density

2006 ◽  
Vol 636 (2) ◽  
pp. 80-85 ◽  
Author(s):  
B. Guberina ◽  
R. Horvat ◽  
H. Nikolić
Keyword(s):  
Dark Energy ◽  
Energy Density ◽  
Vacuum Energy ◽  
Vacuum Energy Density ◽  
Dynamical Dark Energy

scholarly journals COSMOLOGY WITH INTERACTING DARK ENERGY

2004 ◽  
Vol 19 (02) ◽  
pp. 117-134 ◽  
Author(s):  
MANASSE R. MBONYE
Keyword(s):  
Dark Energy ◽  
Vacuum Energy ◽  
Dynamical Problem ◽  
Cosmic Acceleration ◽  
Vacuum Energy Density ◽  
Coincidence Problem ◽  
Coupled Oscillations ◽  
Periodic Acceleration ◽  
Observational Techniques ◽  
The Universe

The early cosmic inflation, when taken along with the recent observations that the universe is currently dominated by a low density vacuum energy, leads to at least two potential problems which modern cosmology must address. First, there is the old cosmological constant problem, with a new twist: the coincidence problem. Secondly, cosmology still lacks a model to predict the observed current cosmic acceleration and to determine whether or not there is a future exit out of this state (as previously in the inflationary case). This constitutes (what is called here) a dynamical problem. Here a framework is proposed to address these two problems, based on treating the cosmic background vacuum (dark) energy as both dynamical and interacting. The universe behaves as a vacuum-driven cosmic engine which, in search of equilibrium, always back-reacts to vacuum-induced accelerations by increasing its inertia (internal energy) through vacuum energy dissipation. The process couples cosmic vacuum (dark) energy to matter to produce future-directed increasingly comparable amplitudes in these fields by setting up oscillations in the decaying vacuum energy density and corresponding sympathetic ones in the matter fields. By putting bounds on the relative magnitudes of these coupled oscillations the model offers a natural and conceptually simple channel to discuss the coincidence problem, while also suggesting a way to deal with the dynamical problem. A result with important observational implications is an equation of state w(t) which specifically predicts a variable, quasi-periodic, acceleration for the current universe. This result can be directly tested by future observational techniques such as SNAP.

scholarly journals Dark Energy is a Phenomenal Effect of the Expanding Universe-Possibility for Experimental Verification.

2020 ◽  
Author(s):  
Siva Prasad Kodukula
Keyword(s):  
Dark Energy ◽  
Experimental Verification ◽  
Quantum Physics ◽  
Vacuum Energy ◽  
Background Radiation ◽  
Big Bang ◽  
Space Time ◽  
Vacuum Energy Density ◽  
The Universe ◽  
Time Density

Abstract Vacuum energy density has been defined and mass formation from ‘space-time’ has been viewed in a different perspective. This explanation for vacuum energy is based on ‘space-time’ and conversion of space in to time keeping ‘space-time density’ as constant. Equations for ‘space-time’ and mutual conversion of space and time have been derived. As a result, new concept of mass creation has been explained. By postulating that space time density of universe is constant, low and high values of cosmological constants has been shown as the exchange of energy between space, time and energy. The concept has been used to explain dark energy concept of the universe. It concluded a result that velocity of light is changing with the apparent expansion of the universe. The derived equation is possible for experimental verification. Obviously it is a contradiction to Big bang model. So the derived equation with the help of quantum concepts explained the 2.7o K cosmic micro wave background radiation. Finally it proposed a relation between diameter of hydrogen atom and Hubble’s constant with another postulate that gives importance to the existence of positive and negative charges below atomic level that describe the basic facts of quantum physics.

scholarly journals SUPERSYMMETRIC BAROTROPIC FRW MODEL AND DARK ENERGY

2009 ◽  
Vol 24 (16) ◽  
pp. 1257-1266
Author(s):  
J. J. ROSALES ◽  
V. I. TKACH
Keyword(s):  
Dark Energy ◽  
Energy Density ◽  
Perfect Fluid ◽  
Vacuum Energy ◽  
Matter Field ◽  
Vacuum Energy Density ◽  
Square Root ◽  
Frw Universe ◽  
Frw Model

Using the superfield approach we construct the n = 2 supersymmetric Lagrangian for the FRW Universe with barotropic perfect fluid as matter field. The obtained supersymmetric algebra allowed us to take the square root of the Wheeler–DeWitt equation and solve the corresponding quantum constraint. This model leads to the relation between the vacuum energy density and the energy density of the dust matter.

Dark energy and dark matter as due to zero point energy

2012 ◽  
Vol 79 (3) ◽  
pp. 327-334 ◽  
Author(s):  
BO LEHNERT
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Energy Density ◽  
Vacuum Energy ◽  
Mass Density ◽  
Zero Point ◽  
Vacuum Energy Density ◽  
Zero Point Energy ◽  
Observable Universe ◽  
Point Energy

AbstractAn attempt is made to explain dark energy and dark matter of the expanding universe in terms of the zero point vacuum energy. This analysis is mainly limited to later stages of an observable nearly flat universe. It is based on a revised formulation of the spectral distribution of the zero point energy, for an ensemble in a defined statistical equilibrium having finite total energy density. The steady and dynamic states are studied for a spherical cloud of zero point energy photons. The ‘antigravitational’ force due to its pressure gradient then represents dark energy, and its gravitational force due to the energy density represents dark matter. Four fundamental results come out of the theory. First, the lack of emitted radiation becomes reconcilable with the concepts of dark energy and dark matter. Second, the crucial coincidence problem of equal orders of magnitude of mass density and vacuum energy density cannot be explained by the cosmological constant, but is resolved by the present variable concepts, which originate from the same photon gas balance. Third, the present approach becomes reconcilable with cosmical dimensions and with the radius of the observable universe. Fourth, the deduced acceleration of the expansion agrees with the observed one. In addition, mass polarity of a generalized gravitation law for matter and antimatter is proposed as a source of dark flow.

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