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 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 ANTI-DE SITTER ISLAND-UNIVERSES FROM 5D STANDING WAVES

2010 ◽  
Vol 25 (25) ◽  
pp. 2131-2143 ◽  
Author(s):  
MERAB GOGBERASHVILI ◽  
DOUGLAS SINGLETON
Keyword(s):  
Infinite Number ◽  
Standing Waves ◽  
Warp Factor ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Landscape Models ◽  
Sitter Spacetime ◽  
Gravitational And Cosmological Constants ◽  
Island Universes ◽  
Cosmological Constants

We construct simple standing wave solutions in a 5D spacetime with a ghost-like scalar field. The nodes of these standing waves are "islands" of 4D anti-de Sitter spacetime. In the case of increasing (decreasing) warp factor, there are a finite (infinite) number of nodes and thus a finite (infinite) number of anti-de Sitter island-universes having different gravitational and cosmological constants. This is similar to the landscape models, which postulate a large number of universes with different parameters.

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 CASIMIR EFFECT FOR A SPHERICAL SHELL IN DE SITTER SPACE–TIME WITH SIGNATURE CHANGE

2008 ◽  
Vol 17 (12) ◽  
pp. 2261-2268
Author(s):  
M. R. SETARE ◽  
F. DARABI
Keyword(s):  
Spherical Shell ◽  
Casimir Effect ◽  
Scalar Fields ◽  
Dirichlet Boundary Conditions ◽  
Massless Scalar ◽  
Late Time ◽  
De Sitter ◽  
Signature Change ◽  
Sitter Background ◽  
Cosmological Constants

We calculate the Casimir stress on a spherical shell in a de Sitter background corresponding to different metric signatures and cosmological constants, for massless scalar fields that satisfy Dirichlet boundary conditions on the shell. We show that a contribution appears due to signature change, which leads to late-time expansion of the bubbles in this background.

scholarly journals CASIMIR STRESS ON PARALLEL PLATES IN DE SITTER SPACE WITH SIGNATURE CHANGE

2007 ◽  
Vol 22 (08n09) ◽  
pp. 1771-1779 ◽  
Author(s):  
M. R. SETARE
Keyword(s):  
Scalar Fields ◽  
Massless Scalar ◽  
Parallel Plates ◽  
False Vacuum ◽  
De Sitter ◽  
Signature Change ◽  
True Vacuum ◽  
Sitter Background ◽  
Robin Boundary ◽  
Cosmological Constants

The Casimir stress on two parallel plates in a de Sitter background corresponding to different metric signatures and cosmological constants is calculated for massless scalar fields satisfying Robin boundary conditions on the plates. Our calculation shows that for the parallel plates with false vacuum between and true vacuum outside, the total Casimir pressure leads to an attraction of the plates at very early universe.

scholarly journals ON THE QUANTUM CHROMODYNAMICS OF A MASSIVE VECTOR FIELD IN THE ADJOINT REPRESENTATION

2013 ◽  
Vol 28 (14) ◽  
pp. 1350054 ◽  
Author(s):  
ALFONSO R. ZERWEKH
Keyword(s):  
Vector Field ◽  
Quantum Chromodynamics ◽  
Extra Dimensions ◽  
Scalar Fields ◽  
Discrete Symmetry ◽  
Adjoint Representation ◽  
Coupling Constants ◽  
Gauge Symmetries ◽  
Gauge Fixing ◽  
Definition Of

In this paper, we explore the possibility of constructing the quantum chromodynamics of a massive color-octet vector field without introducing higher structures like extended gauge symmetries, extra dimensions or scalar fields. We show that gauge invariance is not enough to constraint the couplings. Nevertheless, the requirement of unitarity fixes the values of the coupling constants, which otherwise would be arbitrary. Additionally, it opens a new discrete symmetry which makes the coloron stable and avoid its resonant production at a collider. On the other hand, a judicious definition of the gauge fixing terms modifies the propagator of the massive field making it well-behaved in the ultraviolet limit. The relation between our model and the more general approach based on extended gauge symmetries is also discussed.

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.

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