CHAOTIC INFLATIONARY SCENARIO IN AN ANISOTROPIC UNIVERSE

1986 ◽  
Vol 01 (02) ◽  
pp. 149-155 ◽  
Author(s):  
B.C. PAUL ◽  
D.P. DATTA ◽  
S. MUKHERJEE
Keyword(s):  
Early Universe ◽  
Anisotropic Universe ◽  
Inflationary Model ◽  
Inflationary Scenario ◽  
Inflationary Phase ◽  
Chaotic Model ◽  
The Universe

The chaotic inflationary model of the early universe, proposed by Linde is studied within the framework of an anisotropic Kantowski-Sachs cosmology. It is shown that the chaotic model naturally leads to an inflationary phase which also helps in the isotropization of the universe.

CHAOTIC INFLATIONARY SCENARIO IN BIANCHI TYPE I SPACETIME

2012 ◽  
Vol 27 (09) ◽  
pp. 1250049 ◽  
Author(s):  
RAJ BALI
Keyword(s):  
Energy Density ◽  
Bianchi Type ◽  
Type I ◽  
Inflationary Model ◽  
Bianchi Type I ◽  
Inflationary Scenario ◽  
Inflationary Phase ◽  
Chaotic Model ◽  
Frw Model ◽  
Frame Work

Chaotic inflationary model of the early universe proposed by Linde7 is investigated in the frame work of Bianchi type I spacetime. To determine inflationary scenario, we assume that scale factor [Formula: see text], λ being a constant, m the mass, V(ϕ) the potential energy density. It is shown that chaotic model leads to an inflationary phase which also helps in isotropization process. The Higg's field (ϕ) is initially large but decreases due to lapse of time in both cases. The assumption R3 = ABC~e3Ht does not lead to FRW model immediately but for large values of t, it reduces to FRW model since shear σ = 0 in FRW model and shear σ ≠ 0 in Bianchi type I model. The physical aspects of the model are also discussed.

scholarly journals Inflation, Microwave Background Anisotropy, and Open Universe Models

1996 ◽  
Vol 168 ◽  
pp. 321-327
Author(s):  
J.A. Frieman
Keyword(s):  
Early Universe ◽  
Large Scale ◽  
Large Scale Structure ◽  
Density Fluctuations ◽  
Inhomogeneous Distribution ◽  
Microwave Background ◽  
Inflationary Scenario ◽  
Open Universe ◽  
The Universe ◽  
Universe Models

The inflationary scenario for the very early universe has proven very attractive, because it can simultaneously solve a number of cosmological puzzles, such as the homogeneity of the Universe on scales exceeding the particle horizon at early times, the flatness or entropy problem, and the origin of density fluctuations for large-scale structure [1]. In this scenario, the observed Universe (roughly, the present Hubble volume) represents part of a homogeneous inflated region embedded in an inhomogeneous space-time. On scales beyond the size of this homogeneous patch, the initially inhomogeneous distribution of energy-momentum that existed prior to inflation is preserved, the scale of the inhomogeneities merely being stretched by the expansion.

SPACE-TIME TORSION, BROKEN LORENTZ SYMMETRY AND INFLATION IN THE EARLY UNIVERSE

1993 ◽  
Vol 08 (24) ◽  
pp. 2249-2257 ◽  
Author(s):  
P. CHATTERJEE ◽  
B. BHATTACHARYA
Keyword(s):  
Early Universe ◽  
Relative Abundance ◽  
Early Stage ◽  
Lorentz Symmetry ◽  
Space Time ◽  
Additional Mechanism ◽  
Inflationary Scenario ◽  
The Universe

We have shown here, a possible scheme of inflationary scenario at an early stage of the universe during the radiation dominated era by introducing a local Lorentz symmetry violating term in the space-time torsion of Einstein-Cartan action in E(4,1) space. This 'additional' mechanism for producing inflation may also suggest the answer to the question of the local relative abundance of particles over antiparticles in the observed universe.

scholarly journals SCALAR PERTURBATIONS IN A PRIMORDIAL INFLATIONARY SCENARIO

2002 ◽  
Vol 17 (20) ◽  
pp. 2758-2758
Author(s):  
J. FABRIS ◽  
Ph. SPINDEL
Keyword(s):  
Phase Transition ◽  
Spectral Index ◽  
Order Phase Transition ◽  
Initial Conditions ◽  
Cosmological Term ◽  
Inflationary Model ◽  
Inflationary Scenario ◽  
Inflationary Phase ◽  
Scalar Perturbations ◽  
Second Order Phase Transition

We compute the spectral index for scalar perturbations generated in a primordial inflationary model2. In this model, the transition of the inflationary phase to the radiative era is achieved through the decay of the cosmological term leading a second order phase transition and the characteristics of the model allow to implement a set of initial conditions where the perturbations display a thermal spectrum when they emerge from the horizon. [Formula: see text] The obtained value for the spectral index is equal to 2, a result that depends very weakly on the various parameters of the model and on the initial conditions used. This "negative" result pleads for the standard inflationary scenario, but of course cannot prove it and the problem of the interpretation of the inflaton remains open2.

scholarly journals ON THE CREATION OF UNIVERSE OUT OF NOTHING

2010 ◽  
Vol 19 (08n10) ◽  
pp. 1309-1313 ◽  
Author(s):  
M. S. BERMAN ◽  
L. A. TREVISAN
Keyword(s):  
Equation Of State ◽  
Early Universe ◽  
Initial Energy ◽  
Semiclassical Approach ◽  
Exponential Expansion ◽  
Inflationary Phase ◽  
The Creation ◽  
The Universe

This work aims at using a semiclassical approach to explain how the universe was created out of nothing, i.e., with no input of initial energy nor mass. The inflationary phase with exponential expansion is accounted for, automatically, by our equation of state for the very early universe.

scholarly journals VARYING c COSMOLOGY AND PLANCK VALUE CONSTRAINTS

1999 ◽  
Vol 14 (35) ◽  
pp. 2437-2446 ◽  
Author(s):  
D. H. COULE
Keyword(s):  
Early Universe ◽  
Big Bang ◽  
Planck Length ◽  
Speed Of Light ◽  
Limited Ability ◽  
Standard Cosmology ◽  
Inflationary Phase ◽  
Planck Time ◽  
The Universe

It has been suggested that by increasing the speed of light during the early universe various cosmological problems of standard big bang cosmology can be overcome, without requiring an inflationary phase. However, we find that as the Planck length and Planck time are then made correspondingly smaller, and together with the need that the universe should not re-enter a Planck epoch, the higher c models have very limited ability to resolve such problems. For a constantly decreasing c, the universe will quickly becomes quantum gravitationally dominated as time increases: the opposite to standard cosmology where quantum behaviour is only ascribed to early times.

scholarly journals QUANTUM-TO-CLASSICAL TRANSITION FOR FLUCTUATIONS IN THE EARLY UNIVERSE

1998 ◽  
Vol 07 (03) ◽  
pp. 455-462 ◽  
Author(s):  
CLAUS KIEFER ◽  
DAVID POLARSKI ◽  
ALEXEI A. STAROBINSKY
Keyword(s):  
Early Universe ◽  
Field Amplitude ◽  
Quantum Mechanical ◽  
Gravitational Effects ◽  
Inflationary Scenario ◽  
Classical Transition ◽  
Expansion Of The Universe ◽  
Hubble Radius ◽  
The Universe ◽  
Specific Quantum

According to the inflationary scenario for the very early Universe, all inhomogeneities in the Universe are of genuine quantum origin. On the other hand, looking at these inhomogeneities and measuring them, clearly no specific quantum mechanical properties are observed. We show how the transition from their inherent quantum gravitational nature to classical behavior comes about — a transition whereby none of the successful quantitative predictions of the inflationary scenario for the present-day universe is changed. This is made possible by two properties. First, the quantum state for the spacetime metric perturbations produced by quantum gravitational effects in the early Universe becomes very special (highly squeezed) as a result of the expansion of the Universe (as long as the wavelength of the perturbations exceeds the Hubble radius). Second, decoherence through the environment distinguishes the field amplitude basis as being the pointer basis. This renders the perturbations presently indistinguishable from stochastic classical inhomogeneities.

scholarly journals IMPLICATIONS OF A QUANTUM MECHANICAL TREATMENT OF THE UNIVERSE

1998 ◽  
Vol 13 (05) ◽  
pp. 347-351 ◽  
Author(s):  
MURAT ÖZER
Keyword(s):  
Quantum Mechanics ◽  
Wave Packet ◽  
Early Universe ◽  
Mechanical Treatment ◽  
Correspondence Principle ◽  
Scale Factor ◽  
Quantum Mechanical ◽  
Quantum Mechanical Treatment ◽  
The Standard Model ◽  
The Universe

We attempt to treat the very early Universe according to quantum mechanics. Identifying the scale factor of the Universe with the width of the wave packet associated with it, we show that there cannot be an initial singularity and that the Universe expands. Invoking the correspondence principle, we obtain the scale factor of the Universe and demonstrate that the causality problem of the standard model is solved.

scholarly journals Displaced new physics at colliders and the early universe before its first second

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Lorenzo Calibbi ◽  
Francesco D’Eramo ◽  
Sam Junius ◽  
Laura Lopez-Honorez ◽  
Alberto Mariotti
Keyword(s):  
Dark Matter ◽  
Early Universe ◽  
Upper Bound ◽  
New Physics ◽  
Early History ◽  
Relic Density ◽  
History Of ◽  
Indirect Information ◽  
The Universe

Abstract Displaced vertices at colliders, arising from the production and decay of long-lived particles, probe dark matter candidates produced via freeze-in. If one assumes a standard cosmological history, these decays happen inside the detector only if the dark matter is very light because of the relic density constraint. Here, we argue how displaced events could very well point to freeze-in within a non-standard early universe history. Focusing on the cosmology of inflationary reheating, we explore the interplay between the reheating temperature and collider signatures for minimal freeze-in scenarios. Observing displaced events at the LHC would allow to set an upper bound on the reheating temperature and, in general, to gather indirect information on the early history of the universe.

scholarly journals Relativistic Cosmology with an Introduction to Inflation

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 276
Author(s):  
Muhammad Zahid Mughal ◽  
Iftikhar Ahmad ◽  
Juan Luis García Guirao
Keyword(s):  
Standard Model ◽  
Early Universe ◽  
Large Scale ◽  
Initial Conditions ◽  
Big Bang ◽  
Relativistic Cosmology ◽  
The Standard Model ◽  
Big Bang Model ◽  
The Big Bang ◽  
The Universe

In this review article, the study of the development of relativistic cosmology and the introduction of inflation in it as an exponentially expanding early phase of the universe is carried out. We study the properties of the standard cosmological model developed in the framework of relativistic cosmology and the geometric structure of spacetime connected coherently with it. The geometric properties of space and spacetime ingrained into the standard model of cosmology are investigated in addition. The big bang model of the beginning of the universe is based on the standard model which succumbed to failure in explaining the flatness and the large-scale homogeneity of the universe as demonstrated by observational evidence. These cosmological problems were resolved by introducing a brief acceleratedly expanding phase in the very early universe known as inflation. The cosmic inflation by setting the initial conditions of the standard big bang model resolves these problems of the theory. We discuss how the inflationary paradigm solves these problems by proposing the fast expansion period in the early universe. Further inflation and dark energy in fR modified gravity are also reviewed.

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