scholarly journals Oscillating Cosmological Solutions in the Modified Theory of Induced Gravity

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Farkhat Zaripov
Keyword(s):  
Hubble Parameter ◽  
Numerical Solutions ◽  
Scalar Fields ◽  
Observational Cosmology ◽  
Linear Potential ◽  
Stochastic Behavior ◽  
Induced Gravity ◽  
Gravitational And Cosmological Constants ◽  
Cosmological Constants ◽  
Modified Theory

This work is the extension of author’s research, where the modified theory of induced gravity (MTIG) is proposed. In the framework of the MTIG, the mechanism of phase transitions and the description of multiphase behavior of the cosmological scenario are proposed. The theory describes two systems (stages): Einstein (ES) and “restructuring” (RS). This process resembles the phenomenon of a phase transition, where different phases (Einstein’s gravitational systems, but with different constants) pass into each other. The hypothesis that such transitions are random and lead to stochastic behavior of cosmological parameters is considered. In our model, effective gravitational and cosmological “constants” arise, which are defined by the “mean square” of the scalar fields. These parameters can be compared with observations related to the phenomenon of dark energy. The aim of the work is to solve equations of MTIG for the case of a quadratic potential and compare them with observational cosmology data. The interaction of fundamental scalar fields and matter in the form of an ideal fluid is introduced and investigated. For the case of Friedmann-Robertson-Walker space-time, numerical solutions of nonlinear MTIG equations are obtained using the qualitative theory of dynamical systems and mathematical computer programs. For the case of a linear potential, examples joining of solutions, the ES and RS stages, of the evolution of the cosmological model are given. It is shown that the values of such parameters as “Hubble parameter” and gravitational and cosmological “constants” in the RS stage contain solutions oscillating near monotonically developing averages or have stochastic behavior due to random transitions to different stages (RS or ES). Such a stochastic behavior might be at the origin of the tension between CMB measurements of the value of the Hubble parameter today and its local measurements.

scholarly journals The Ambiguity in the Definition and Behavior of the Gravitational and Cosmological `Coupling Constants’ in the Theory of Induced Gravity

Symmetry ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 81 ◽  
Author(s):  
Farkhat Zaripov
Keyword(s):  
Gravitational Interaction ◽  
Scalar Fields ◽  
Coupling Constants ◽  
De Sitter ◽  
Induced Gravity ◽  
Mean Values ◽  
Gravitational And Cosmological Constants ◽  
Centrally Symmetric ◽  
Walker Metric ◽  
Cosmological Constants

This work is the extension of author`s research, where the modified theory of induced gravity (MTIG) is proposed. The theory describes two systems (stages): Einstein (ES) and “restructuring” (RS). We consider equations with quadratic potential that are symmetric with respect to scale transformations. The solutions of the equations obtained for the case of spaces defined by the Friedman-Robertson-Walker metric, as well as for a centrally symmetric space are investigated. In our model arise effective gravitational and cosmological “constants”, which are defined by the “mean square” of the scalar fields. In obtained solutions the values of such parameters as “Hubble parameter”, gravitational and cosmological “constants” in the RS stage fluctuate near monotonically evolving mean values. These parameters are matched with observational data, described as phenomena of dark energy and dark matter. The MTIG equations for the case of a centrally symmetric gravitational field, in addition to the Schwarzschild-de Sitter solutions, contain solutions that lead to the new physical effects at large distances from the center. The Schwarzschild-Sitter solution becomes unstable and enters the oscillatory regime. For distances greater than a certain critical value, the following effects can appear: deviation from General relativity and Newton’s law of gravitational interaction, antigravity.

scholarly journals Dark Matter as a Result of Field Oscillations in the Modified Theory of Induced Gravity

Symmetry ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 41 ◽  
Author(s):  
Farkhat Zaripov
Keyword(s):  
Dark Matter ◽  
Mass Effect ◽  
Quadratic Potential ◽  
Induced Gravity ◽  
Mean Values ◽  
Gravitational And Cosmological Constants ◽  
Centrally Symmetric ◽  
Arbitrary Potential ◽  
Cosmological Constants ◽  
Modified Theory

The paper studies the modified theory of induced gravity (MTIG). The solutions of the MTIG equations contain two branches (stages): Einstein (ES) and “restructuring” (RS). Previously, solutions were found that the values of such parameters as the “Hubble parameter”, gravitational and cosmological “constants” at the RS stage, fluctuate near monotonously developing mean values. This article gives MTIG equations with arbitrary potential. Solutions of the equations of geodesic curves are investigated for the case of centrally symmetric space and quadratic potential at the RS stage. The oscillatory nature of the solutions leads to the appearance of a gravitational potential containing a spectrum of minima, as well as to antigravity, which is expressed by acceleration directed from the center. Such solutions lead to the distribution of the potential of the gravitational field creating an additional mass effect at large distances and are well suited for modeling the effect of dark matter in galaxies. The solutions of the equation of geodesic lines are obtained and analyzed. We found that the transition from flat asymptotics to oscillatory asymptotics at large distances from the center with a combination of the presence of antigravity zones leads to a rich variety of shapes and dynamics of geodesic curves and to the formation of complex structures.

scholarly journals WKB WAVE FUNCTIONS WITH THE INDUCED GRAVITY THEORY

1999 ◽  
Vol 14 (31) ◽  
pp. 2179-2185 ◽  
Author(s):  
ZONG-HONG ZHU ◽  
LI CAO
Keyword(s):  
Boundary Condition ◽  
Wave Functions ◽  
Gravity Theory ◽  
Wkb Method ◽  
Induced Gravity ◽  
Maximum Value ◽  
Gravitational And Cosmological Constants ◽  
Classical Models ◽  
Cosmological Constants ◽  
The Universe

The Wheeler–DeWitt equation for the induced gravity theory is constructed in the mini superspace approximation, and then solved using the WKB method under three types of boundary condition proposed respectively by Hartle & Hawking ("no boundary"), Linde and Vilenkin ("tunneling from nothing"). It is found that no matter how the gravitational and cosmological "constants" vary in the classical models, they will acquire constant values when the universe comes from quantum creation, and that, in particular, the resulting tunneling wave function under the Linde or Vilenkin boundary condition reaches its maximum value if the cosmological constant vanishes.

scholarly journals CAUSAL BULK VISCOUS DISSIPATIVE ISOTROPIC COSMOLOGIES WITH VARIABLE GRAVITATIONAL AND COSMOLOGICAL CONSTANTS

2002 ◽  
Vol 11 (08) ◽  
pp. 1265-1283 ◽  
Author(s):  
M. K. MAK ◽  
T. HARKO ◽  
J. A. BELINCHÓN
Keyword(s):  
Cosmological Constant ◽  
Hubble Parameter ◽  
Early Period ◽  
Viscosity Coefficient ◽  
Field Equations ◽  
Gravitational And Cosmological Constants ◽  
Bulk Viscous ◽  
Cosmological Constants ◽  
Bulk Viscosity Coefficient ◽  
The Universe

We consider the evolution of a flat Friedmann–Robertson–Walker Universe, filled with a causal bulk viscous cosmological fluid, in the presence of variable gravitational and cosmological constants. The basic equation for the Hubble parameter, generalizing the evolution equation in the case of constant gravitational coupling and cosmological term is derived, under the supplementary assumption that the total energy of the Universe is conserved. By assuming that the cosmological constant is proportional to the square of the Hubble parameter and a power law dependence of the bulk viscosity coefficient, temperature and relaxation time on the energy density of the cosmological fluid, two classes of exact solutions of the field equations are obtained. In the first class of solutions the Universe ends in an inflationary era, while in the second class of solutions the expan-sion of the Universe is noninflationary for all times. In both models the cosmological "constant" is a decreasing function of time, while the gravitational "constant" increases in the early period of evolution of the Universe and tends in the large time limit to a constant value.

scholarly journals COSMOLOGICAL MODELS WITH VARIABLE GRAVITATIONAL AND COSMOLOGICAL CONSTANTS IN R2GRAVITY

2006 ◽  
Vol 15 (02) ◽  
pp. 189-198 ◽  
Author(s):  
P. S. DEBNATH ◽  
B. C. PAUL
Keyword(s):  
Model Building ◽  
Cosmological Models ◽  
Higher Derivative ◽  
Gravitational And Cosmological Constants ◽  
Cosmological Solutions ◽  
Cosmological Constants ◽  
The Universe ◽  
Hilbert Action

We consider the evolution of a flat Friedmann–Roberstson–Walker Universe in a higher derivative theory, including αR2terms for the Einstein–Hilbert action in the presence of variable gravitational and cosmological constants. We study the evolution of the gravitational and cosmological constants in the radiation and matter domination era of the universe. We present new cosmological solutions which are physically interesting for model building.

scholarly journals Conformal gravity with electrodynamics for fermion fields and their symmetry breaking mechanism

2014 ◽  
Vol 11 (03) ◽  
pp. 1450019 ◽  
Author(s):  
Luca Fabbri
Keyword(s):  
Scalar Fields ◽  
Specific Form ◽  
Conformal Gravity ◽  
Field Equations ◽  
Cosmological Constant Problem ◽  
Conformal Theory ◽  
Fermion Fields ◽  
Breaking Mechanism ◽  
Cosmological Constants ◽  
Dirac Spinors

In this paper, we consider an axial torsion to build metric-compatible connections in conformal gravity, with gauge potentials; the geometric background is filled with Dirac spinors: scalar fields with suitable potentials are added eventually. The system of field equations is worked out to have torsional effects converted into spinorial self-interactions: the massless spinors display self-interactions of a specific form that gives them the features they have in the non-conformal theory but with the additional character of renormalizability, and the mechanisms of generation of mass and cosmological constants become dynamical. As a final step we will address the cosmological constant problem and the coincidence issue.

scholarly journals AN EFFECTIVE STRONG GRAVITY INDUCED BY QCD

1995 ◽  
Vol 10 (23) ◽  
pp. 1711-1718 ◽  
Author(s):  
VINCENT BRINDEJONC ◽  
GILLES COHEN-TANNOUDJI
Keyword(s):  
Strong Gravity ◽  
Gravitational And Cosmological Constants ◽  
Cosmological Constants

We show that, when quantized on a “curved intra-hadronic spacetime”, QCD induces an effective gravitation-like interaction with gravitational and cosmological constants in the GeV range.

A STUDY ABOUT THE SOLUTIONS OF SCHRÖDINGER EQUATION WITH AN ASYMPTOTICALLY LINEAR POTENTIAL

1996 ◽  
Vol 11 (03) ◽  
pp. 207-209 ◽  
Author(s):  
ELSO DRIGO FILHO
Keyword(s):  
Quantum Mechanics ◽  
Schrödinger Equation ◽  
Analytical Solutions ◽  
Schrodinger Equation ◽  
Numerical Solutions ◽  
Expansion Method ◽  
Linear Potential ◽  
Asymptotically Linear

We determine the solutions of the Schrödinger equation for an asymptotically linear potential. Analytical solutions are obtained by superalgebra in quantum mechanics and we establish when these solutions are possible. Numerical solutions for the spectra are obtained by the shifted 1/N expansion method.

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