scholarly journals NON-MINIMAL COSMOLOGICAL MODEL IN MODIFIED YANG–MILLS THEORY

2011 ◽  
Vol 26 (26) ◽  
pp. 1965-1973 ◽  
Author(s):  
V. K. SHCHIGOLEV ◽  
G. N. OREKHOVA
Keyword(s):  
Cosmological Model ◽  
Power Law ◽  
Cosmic Acceleration ◽  
Gravitational Coupling ◽  
Frw Cosmology ◽  
General Study ◽  
Yang Mills ◽  
Basic Equations ◽  
M Theory ◽  
Friedmann Robertson Walker

In this paper, we consider a model of non-minimal modified Yang–Mills (Y-M) theory in the Friedmann–Robertson–Walker (FRW) cosmology, in which the Y-M field couples to the scalar curvature through a function of its first invariant. We show that cosmic acceleration can be realized due to non-minimal gravitational coupling of the modified Y-M theory. Besides general study, we consider in detail the case of power-law coupling function. We derive the basic equations for the cosmic scale factor in our model, and provide several examples of their solutions.

scholarly journals On multifluid perturbations in scalar–tensor cosmology

2020 ◽  
pp. 2050120
Author(s):  
Joseph Ntahompagaze ◽  
Shambel Sahlu ◽  
Amare Abebe ◽  
Manasse R. Mbonye
Keyword(s):  
Scalar Field ◽  
Energy Density ◽  
Power Law ◽  
Scalar Tensor Theory ◽  
Frw Cosmology ◽  
Static Approximation ◽  
Covariant Approach ◽  
Tensor Theory ◽  
Text Model ◽  
Friedmann Robertson Walker

In this paper, the scalar–tensor theory is applied to the study of perturbations in a multifluid universe, using the [Formula: see text] covariant approach. Both scalar and harmonic decompositions are instituted on the perturbation equations. In particular, as an application, we study perturbations on a background Friedmann-Robertson-Walker (FRW) cosmology consisting of both radiation and dust in the presence of a scalar field. We consider both radiation-dominated and dust-dominated epochs, respectively, and study the results. During the analysis, quasi-static approximation is instituted. It is observed that the fluctuations of the energy density decrease with increasing redshift, for different values of [Formula: see text] of a power-law [Formula: see text] model.

scholarly journals Inhomogeneous viscous dark fluid coupled with dark matter in the FRW universe

2014 ◽  
Vol 29 (25) ◽  
pp. 1450132 ◽  
Author(s):  
E. Elizalde ◽  
V. V. Obukhov ◽  
A. V. Timoshkin
Keyword(s):  
Dark Matter ◽  
Cosmological Model ◽  
Viscous Fluid ◽  
Critical Points ◽  
Cosmic Acceleration ◽  
Frw Universe ◽  
Dark Fluid ◽  
Different Types ◽  
Friedmann Robertson Walker

A cosmological model with an inhomogeneous viscous dark fluid coupled with dark matter in a flat Friedmann–Robertson–Walker (FRW) universe is investigated. The influence of dark matter on the behavior of an inhomogeneous viscous fluid of this kind, responsible for cosmic acceleration and for the appearance of different types of singularities, is analyzed in detail. In particular, the critical points corresponding to the solutions of the background equations in a useful approximation are obtained explicitly.

scholarly journals Local G2-manifolds, Higgs bundles and a colored quantum mechanics

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Max Hübner
Keyword(s):  
Quantum Mechanics ◽  
Gauge Theories ◽  
Supersymmetric Quantum Mechanics ◽  
Higgs Bundle ◽  
Higgs Bundles ◽  
View Point ◽  
Yang Mills ◽  
G2 Manifolds ◽  
Supersymmetric Gauge ◽  
M Theory

Abstract M-theory on local G2-manifolds engineers 4d minimally supersymmetric gauge theories. We consider ALE-fibered G2-manifolds and study the 4d physics from the view point of a partially twisted 7d supersymmetric Yang-Mills theory and its Higgs bundle. Euclidean M2-brane instantons descend to non-perturbative effects of the 7d supersymmetric Yang-Mills theory, which are found to be in one to one correspondence with the instantons of a colored supersymmetric quantum mechanics. We compute the contributions of M2-brane instantons to the 4d superpotential in the effective 7d description via localization in the colored quantum mechanics. Further we consider non-split Higgs bundles and analyze their 4d spectrum.

Signature change in p-adic and noncommutative FRW cosmology

2014 ◽  
Vol 29 (27) ◽  
pp. 1450155 ◽  
Author(s):  
Goran S. Djordjevic ◽  
Ljubisa Nesic ◽  
Darko Radovancevic
Keyword(s):  
Loop Quantum Gravity ◽  
Initial Conditions ◽  
Planck Scale ◽  
The Other ◽  
Frw Cosmology ◽  
Signature Change ◽  
Discrete Nature ◽  
Frw Metric ◽  
The Universe ◽  
Friedmann Robertson Walker

The significant matter for the construction of the so-called no-boundary proposal is the assumption of signature transition, which has been a way to deal with the problem of initial conditions of the universe. On the other hand, results of Loop Quantum Gravity indicate that the signature change is related to the discrete nature of space at the Planck scale. Motivated by possibility of non-Archimedean and/or noncommutative structure of space–time at the Planck scale, in this work we consider the classical, p-adic and (spatial) noncommutative form of a cosmological model with Friedmann–Robertson–Walker (FRW) metric coupled with a self-interacting scalar field.

scholarly journals COSMIC ACCELERATION AND M THEORY COSMOLOGY

2004 ◽  
Vol 19 (13n16) ◽  
pp. 1093-1098 ◽  
Author(s):  
ISHWAREE P. NEUPANE
Keyword(s):  
Dark Energy ◽  
First Principles ◽  
Cosmic Acceleration ◽  
Curved Spaces ◽  
Short Overview ◽  
M Theory

This is a short overview of spatially flat (or open) four-dimensional accelerating cosmologies for some simple exponential potentials obtained by string or M theory compactification on some non-trivial curved spaces, which may lead to some striking results, e.g., the observed cosmic acceleration and the scale of the dark energy from first principles.

scholarly journals A CHERN–SIMONS E8 GAUGE THEORY OF GRAVITY IN D = 15, GRAND UNIFICATION AND GENERALIZED GRAVITY IN CLIFFORD SPACES

2007 ◽  
Vol 04 (08) ◽  
pp. 1239-1257 ◽  
Author(s):  
CARLOS CASTRO
Keyword(s):  
Gauge Theory ◽  
Grand Unification ◽  
De Sitter ◽  
Sitter Group ◽  
Yang Mills ◽  
Theory Of Gravity ◽  
M Theory ◽  
Chern Simons ◽  
Topological Part ◽  
Gauge Theory Of Gravity

A novel Chern–Simons E8 gauge theory of gravity in D = 15 based on an octicE8 invariant expression in D = 16 (recently constructed by Cederwall and Palmkvist) is developed. A grand unification model of gravity with the other forces is very plausible within the framework of a supersymmetric extension (to incorporate spacetime fermions) of this Chern–Simons E8 gauge theory. We review the construction showing why the ordinary 11D Chern–Simons gravity theory (based on the Anti de Sitter group) can be embedded into a Clifford-algebra valued gauge theory and that an E8 Yang–Mills field theory is a small sector of a Clifford (16) algebra gauge theory. An E8 gauge bundle formulation was instrumental in understanding the topological part of the 11-dim M-theory partition function. The nature of this 11-dim E8 gauge theory remains unknown. We hope that the Chern–Simons E8 gauge theory of gravity in D = 15 advanced in this work may shed some light into solving this problem after a dimensional reduction.

scholarly journals Quadratic integrals of a multi-scalar cosmological model

2020 ◽  
Vol 35 (10) ◽  
pp. 2050068 ◽  
Author(s):  
Sameerah Jamal
Keyword(s):  
Scalar Field ◽  
Cosmological Model ◽  
Conservation Laws ◽  
Analytical Solutions ◽  
Physical System ◽  
Noether Symmetries ◽  
Spatial Curvature ◽  
Special Case ◽  
Friedmann Robertson Walker ◽  
Field Integral

In the context of Friedmann–Robertson–Walker (FRW) spacetime with zero spatial curvature, we consider a multi-scalar tensor cosmology model under the pretext of obtaining quadratic conservation laws. We propose two new interaction potentials of the scalar field. Integral to this task is the existence of dynamical Noether symmetries which are Lie–Bäcklund transformations of the physical system. Finally, analytical solutions of the field are found corresponding to each new model. In one of the models, we find that the scale factor mimics [Formula: see text]-cosmology in a special case.

scholarly journals A COSMOLOGICAL MODEL WITH FERMIONIC FIELD

2010 ◽  
Vol 25 (13) ◽  
pp. 2735-2746 ◽  
Author(s):  
R. RAKHI ◽  
G. V. VIJAYAGOVINDAN ◽  
K. INDULEKHA
Keyword(s):  
Dark Energy ◽  
Cosmological Model ◽  
The Self ◽  
Late Time ◽  
Fermionic Field ◽  
Energy Field ◽  
Late Time Acceleration ◽  
Higher Order Terms ◽  
Interaction Term ◽  
M Theory

In this work, a cosmological model inspired by string/M-theory with fermionic field is taken into consideration. Here it is investigated whether the introduction of a non-Dirac fermionic field — characterized by an interaction term — affects the cosmological evolution. The self-interaction potential is considered as a combination of the scalar and pseudoscalar invariants. It is observed that the fermionic field under consideration behaves like an inflation field for the early universe and later on, as a dark energy field. The late time acceleration becomes more prominent by the addition of the interaction term. There is a slight decrease for the inflation peak as well as for the energy density. We see that the addition of higher-order terms to the fermionic part of Lagrangian does not significantly change either the inflation or the late time acceleration behavior.

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