scholarly journals A higher dimensional cosmological model for the search of dark energy source

Author(s):  
Pheiroijam Suranjoy Singh ◽  
Kangujam Priyokumar Singh

With due consideration of reasonable cosmological assumptions within the limit of the present cosmological scenario, we have analyzed a spherically symmetric metric in 5D setting within the framework of Lyra manifold. The model universe is predicted to be a DE model, dominated by vacuum energy. The model represents an oscillating model, each cycle evolving with a big bang and ending at a big crunch, undergoing a series of bounces. The universe is isotropic and undergoes super-exponential expansion. The value of Hubble’s parameter is measured to be [Formula: see text] which is very close to [Formula: see text], the value estimated by the latest Planck 2018 result. A detailed discussion on the cosmological parameters obtained is also presented with graphs.

2017 ◽  
Vol 32 (28) ◽  
pp. 1750152
Author(s):  
Emiliano Marachlian ◽  
I. E. Sánchez G. ◽  
Osvaldo P. Santillán

A cosmological scenario where dark matter interacts with a variable vacuum energy for a spatially flat Friedmann–Robertson–Walker (FRW) spacetime is proposed and analyzed to show that with a linear equation of state and a particular interaction in the dark sector it is possible to get a model of an Emergent Universe. In addition, the viability of two particular models is studied by taking into account the recent observations. The updated observational Hubble data and the JLA supernovae data are used in order to constraint the cosmological parameters of the models and estimate the amount of dark energy in the radiation era. It is shown that the two models fulfil the severe bounds of [Formula: see text] at the 2[Formula: see text] level of Planck.


Author(s):  
Jae-Kwang Hwang

The properties of the charged dark matters are discussed in terms of the new three-dimensional quantized space model. Because of the graviton evaporations, the very small Coulomb’s constant (k(dd)) of 10 −48 k and large gravitation constant (GN(dd)) of 106 GN for the charged dark matters at the present time are expected. The tentative values of G and k are used for the explanation purpose. Therefore, Fc(mm) > Fg(dd) > Fg(mm) > Fg(dm) > Fc(dd) > Fc(dm) = Fc(lq) = 0 for the proton-like particle. Also, the gravitation constant has been changed with increasing of the time because of the graviton evaporation. In the present work, the B1, B2 and B3 bastons with the condition of k(mm) = k >> k(dd) > k(dm) = 0 are explained as the good candidates of the dark matters. Also, the particle creation, dark matters and dark energy could be deeply associated with the changing gravitation constants (G). It is expected that the changing process of the gravitation constant between the matters from GN(mm) ≈ 1036 GN to GN(mm) = GN happened mostly near the inflation period. Therefore, during most of the universe evolution the gravitation constant could be taken as GN(mm) = GN. And the effective charges and effective rest masses of the particles are defined in terms of the fixed Coulomb’s constant (k) and fixed gravitation constant (GN). Then, the effective charge of the B1 dark matter with EC = −2/3 e is (EC)eff = −2/3·10−24 e. It is concluded that the photons, gravitons and dark matters are the first particles created since the big bang. The particles can be created from the decay of the matter universe and the pair production of the particle and anti-particle with decreasing of the gravitation constant (GN(mm)). Also, the weak force, strong force and dark matter force bosons are created from the interactions of the elementary particles with the T fluctuations of the vacuum energy.


2020 ◽  
Author(s):  
Siva Prasad Kodukula

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.


2018 ◽  
Vol 51 (2) ◽  
pp. 505-513 ◽  
Author(s):  
Angela Altomare ◽  
Nicola Corriero ◽  
Corrado Cuocci ◽  
Aurelia Falcicchio ◽  
Anna Moliterni ◽  
...  

The hybrid big bang–big crunch algorithm is a combination of a global optimization algorithm inspired by one of the theories of the evolution of the universe, named the big bang and big crunch theory, and the simulated annealing method. The procedure was implemented in the latest version of the programEXPOand applied to crystal-structure solution from powder diffraction data. Several aspects of the hybrid big bang–big crunch algorithm can be further optimized with the aim of obtaining good quality solutions in a shorter computation time. In the present study, the hybrid big bang–big crunch procedure has been combined with the greedy randomized adaptive search procedure (GRASP) and some steps of the algorithm have been improved. The new approach, implemented in theEXPOpackage, has been successfully tested on numerous known crystal structures.


2009 ◽  
Vol 24 (23) ◽  
pp. 1847-1856 ◽  
Author(s):  
SHRI RAM ◽  
M. K. VERMA ◽  
MOHD ZEYAUDDIN

In this paper, a spatially homogeneous and anisotropic Bianchi type V model filled with an imperfect fluid with both viscosity and heat conduction is investigated within the framework of Lyra's geometry. Exact solutions of the field equations are obtained by applying a special law of variation for Hubble's parameter which yields a constant value of the deceleration parameter. Two different physically viable models of the universe are presented in two types of cosmologies, one with power-law expansion and other one with exponential expansion. Cosmological model with power-law expansion has an initial big-bang type singularity at t = 0 whereas the model with exponential expansion has a singularity in the infinite past. The physical and dynamical properties of the models are discussed.


2003 ◽  
Vol 12 (06) ◽  
pp. 1053-1065 ◽  
Author(s):  
J. PONCE DE LEON

We consider the evolution of a 4D-universe embedded in a five-dimensional (bulk) world with a large extra dimension and a cosmological constant. The cosmology in 5D possesses "wave-like" character in the sense that the metric coefficients in the bulk are functions of the extra coordinate and time in a way similar to a pulse or traveling wave propagating along the fifth dimension. This assumption is motivated by some recent work presenting the big-bang as a higher dimensional shock wave. We show that this assumption, together with an equation of state for the effective matter quantities in 4D, allows Einstein's equations to be fully integrated. We then recover the familiar FLRW universes, on the four-dimensional hypersurfaces orthogonal to the extra dimension. Regarding the extra dimension we find that it is growing in size if the universe is speeding up its expansion. We also get an estimate for the relative change of the extra dimension over time. This estimate could have important observational implications, notably for the time variation of rest mass, electric charge and the gravitational "constant". Our results extend previous ones in the literature.


2008 ◽  
Vol 17 (03n04) ◽  
pp. 685-690 ◽  
Author(s):  
LAWRENCE M. KRAUSS ◽  
ROBERT J. SCHERRER

We demonstrate that as we extrapolate the current ΛCDM universe forward in time, all evidence of the Hubble expansion will disappear, so that observers in our "island universe" will be fundamentally incapable of determining the true nature of the universe, including the existence of the highly dominant vacuum energy, the existence of the CMB, and the primordial origin of light elements. With these pillars of the modern Big Bang gone, this epoch will mark the end of cosmology and the return of a static universe. In this sense, the coordinate system appropriate for future observers will perhaps fittingly resemble the static coordinate system in which the de Sitter universe was first presented.


2020 ◽  
Author(s):  
Siva Prasad Kodukula

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.


LOGOS ◽  
2020 ◽  
Vol 17 (2) ◽  
pp. 15-45
Author(s):  
Leo Agung Srie Gunawan

The problem of the universe having a great mystery encloses the big question about its origin. To answer the origin of universe, generally, there are two approaches, namely faith and science. The main question has to be replied: “What do the differences and the similarity of them?” The approach of faith bases on the inquiry of “who causes the existence of the universe”. This approach states that the origin of universe was created by God and hence, it was formed by God from a nothingness (creatio ex nihilo). This is known as the theorem of creation. Furthermore, the scientific approach is grounded on the research of “how the universe was formed in the beginning”. This oncoming being explained by the Big Bang Theory, which is continued by the Big Crunch Theory, asserts that the origin of universe came from the prime matter which exploded incredibly in a such a way that the formation process of the universe took place (the singularity). This is well-known as the theory of evolution (the cosmological evolution). In conclusion, the scientific approach explaining the process of creation and the faith one answering the actor of it are complementary.


2021 ◽  
Vol 4 (3) ◽  

The Cosmic Time Hypothesis (CTH) presented in this paper is a purely axiomatic theory. In contrast to today's standard model of cosmology, the ɅCDM model, it does not contain empirical parameters such as the cosmological constant Ʌ, nor does it contain sub-theories such as the inflation theory. The CTH was developed solely on the basis of the general theory of relativity (GRT), aiming for the greatest possible simplicity. The simplest cosmological model permitted by ART is the Einstein-de Sitter model. It is the basis for solving some of the fundamental problems of cosmology that concern us today. First of all, the most important results of the CTH: It solves one of the biggest problems of cosmology the problem of the cosmological constant (Ʌ)-by removing the relation between and the vacuum energy density ɛv (Λ=0, ɛv > 0). According to the CTH, the vacuum energy density ɛv is not negative and constant, as previously assumed, but positive and time-dependent (ɛv ̴ t -2). ɛv is part of the total energy density (Ɛ) of the universe and is contained in the energy-momentum tensor of Einstein's field equations. Cosmology is thus freed from unnecessary ballast, i.e. a free parameter (= natural constant) is omitted (Ʌ = 0). Conclusion: There is no "dark energy"! According to the CTH, the numerical value of the vacuum energy density v is smaller by a factor of ≈10-122 than the value calculated from quantum field theory and is thus consistent with observation. The measurement data obtained from observations of SNla supernovae, which suggest a currently accelerated expansion of the universe, result - if interpreted from the point of view of the CTH - in a decelerated expansion, as required by the Einstein-de Sitter universe. Dark matter could also possibly not exist, because the KZH demands that the "gravitational constant" is time-dependent and becomes larger the further the observed objects are spatially and thus also temporally distant from us. Gravitationally bound local systems, e.g. Earth - Moon or Sun - Earth, expand according to the same law as the universe. This explains why Hubble's law also applies within very small groups of galaxies, as observations show. The CTH requires that the strongest force (strong nuclear force) and the weakest (gravitational force) at Planck time (tp ≈10-43 seconds after the "big bang") when all forces of nature are supposed to have been united in a single super force, were of equal magnitude and had the same range. According to the KZH, the product of the strength and range of the gravitational force is constant, i.e. independent of time, and is identical to the product of the strength and range of the strong nuclear force. At Planck time, the universe had the size of an elementary particle (Rp = rE ≈10-15 m). This value also corresponds to the range of the strong nuclear force (Yukawa radius) and the Planck length at Planck time. The CTH provides a possible explanation for Mach's first and second principles. It solves some old problems of the big bang theory in a simple and natural way. The problem of the horizon, flatness, galaxy formation and the age of the world. The inflation theory thus becomes superfluous. • The CTH provides the theoretical basis for the theory of Earth expansion • In Cosmic Time, there was no Big Bang. The universe is infinitely old. • Unlike other cosmological models, the CTH does not require defined "initial conditions" because there was no beginning. • The CTH explains why the cosmic expansion is permanently in an unstable state of equilibrium, which is necessary for a long-term flat (Euclidean), evolutionarily developing universe.


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