The evolution equation of the scalar field in the new inflationary universe

1987 ◽  
Vol 34 (4) ◽  
pp. 481-490 ◽  
Author(s):  
A. Ringwald
Keyword(s):  
Scalar Field ◽  
Evolution Equation ◽  
Inflationary Universe

scholarly journals Assessment of an Evolution Equation for the Displacement Speed of a Constant-Density Reactive Scalar Field

2020 ◽  
Author(s):  
Rixin Yu ◽  
Thommie Nilsson ◽  
Geert Brethouwer ◽  
Nilanjan Chakraborty ◽  
Andrei Lipatnikov
Keyword(s):  
Scalar Field ◽  
Evolution Equation ◽  
Constant Density ◽  
Displacement Speed ◽  
Reactive Scalar

Classical behavior of a scalar field in the inflationary universe

1988 ◽  
Vol 308 (4) ◽  
pp. 868-884 ◽  
Author(s):  
Misao Sasaki ◽  
Yasusada Nambu ◽  
Ken-ichi Nakao
Keyword(s):  
Scalar Field ◽  
Inflationary Universe ◽  
Classical Behavior

scholarly journals ON THE QUASI-ISOTROPIC INFLATIONARY SOLUTION

2003 ◽  
Vol 12 (10) ◽  
pp. 1845-1857 ◽  
Author(s):  
GIOVANNI IMPONENTE ◽  
GIOVANNI MONTANI
Keyword(s):  
Scalar Field ◽  
Cosmological Constant ◽  
Small Function ◽  
Inflationary Universe ◽  
Arbitrary Form ◽  
Metric Tensor ◽  
Dominant Term ◽  
First Order ◽  
Effective Cosmological Constant ◽  
Relativistic Matter

In this paper we find a solution for a quasi-isotropic inflationary Universe which allows to introduce in the problem a certain degree of inhomogeneity. We consider a model which generalizes the (flat) FLRW one by introducing a first order inhomogeneous term, whose dynamics is induced by an effective cosmological constant. The 3-metric tensor is constituted by a dominant term, corresponding to an isotropic-like component, while the amplitude of the first order one is controlled by a "small" function η(t). In a Universe filled with ultra relativistic matter and a real self-interacting scalar field, we discuss the resulting dynamics, up to first order in η, when the scalar field performs a slow roll on a plateau of a symmetry breaking configuration and induces an effective cosmological constant. We show how the spatial distribution of the ultra relativistic matter and of the scalar field admits an arbitrary form but nevertheless, due to the required inflationary e-folding, it cannot play a serious dynamical role in tracing the process of structures formation (via the Harrison–Zeldovic spectrum). As a consequence, this paper reinforces the idea that the inflationary scenario is incompatible with a classical origin of the large scale structures.

scholarly journals A Riccati equation based approach to isotropic scalar field cosmologies

2014 ◽  
Vol 23 (07) ◽  
pp. 1450063 ◽  
Author(s):  
Tiberiu Harko ◽  
Francisco S. N. Lobo ◽  
M. K. Mak
Keyword(s):  
Scalar Field ◽  
Evolution Equation ◽  
Interaction Potential ◽  
Arbitrary Function ◽  
Field Potential ◽  
Type Equation ◽  
Scalar Fields ◽  
Cosmological Models ◽  
Late Time ◽  
Field Equations

Gravitationally coupled scalar fields ϕ, distinguished by the choice of an effective self-interaction potential V(ϕ), simulating a temporarily nonvanishing cosmological term, can generate both inflation and late time acceleration. In scalar field cosmological models the evolution of the Hubble function is determined, in terms of the interaction potential, by a Riccati type equation. In the present work, we investigate scalar field cosmological models that can be obtained as solutions of the Riccati evolution equation for the Hubble function. Four exact integrability cases of the field equations are presented, representing classes of general solutions of the Riccati evolution equation. The solutions correspond to cosmological models in which the Hubble function is proportional to the scalar field potential plus a linearly decreasing function of time, models with the time variation of the scalar field potential proportional to the potential minus its square, models in which the potential is the sum of an arbitrary function and the square of the function integral, and models in which the potential is the sum of an arbitrary function and the derivative of its square root, respectively. The cosmological properties of all models are investigated in detail, and it is shown that they can describe the inflationary or the late accelerating phase in the evolution of the universe.

scholarly journals Quintessential Inflation with Dynamical Higgs Generation as an Affine Gravity

2020 ◽  
Author(s):  
David Benisty ◽  
Eduardo Guendelman ◽  
Emil Nissimov ◽  
Svetlana Pacheva
Keyword(s):  
Scalar Field ◽  
Modified Gravity ◽  
Riemannian Metric ◽  
Explicit Representation ◽  
Inflationary Universe ◽  
Inflationary Model ◽  
Scale Invariant ◽  
Inflationary Scenario ◽  
Higgs Effect ◽  
Affine Gravity

First, we propose a scale-invariant modified gravity interacting with a neutral scalar inflaton and a Higgs-like SU(2)xU(1) iso-doublet scalar field based on the formalism of non-Riemannian (metric-independent) spacetime volume-elements. This model describes in the physical Einstein frame a quintessential inflationary scenario driven by the "inflaton" together with gravity-inflaton assisted dynamical spontaneous SU(2)xU(1) symmetry breaking in the post-inflationary universe, whereas SU(2)xU(1) symmetry remains intact in the inflationary epoch. Next, we find the explicit representation of the latter quintessential inflationary model with a dynamical Higgs effect as an Eddington-type purely affine gravity.

CLASSICAL PERTURBATIONS FROM DECOHERENCE OF QUANTUM FLUCTUATIONS IN THE INFLATIONARY UNIVERSE

1990 ◽  
Vol 05 (28) ◽  
pp. 2311-2317 ◽  
Author(s):  
ROBERT BRANDENBERGER ◽  
RAYMOND LAFLAMME ◽  
MILAN MIJIĆ
Keyword(s):  
Scalar Field ◽  
Coherence Length ◽  
Quantum Fluctuations ◽  
Inflationary Universe ◽  
De Sitter ◽  
Density Perturbations ◽  
Hubble Radius ◽  
Universe Models

The evolution of a scalar field interacting with an environment in the de Sitter phase of an inflationary Universe is studied. The environment is taken to be a second scalar field. It is shown that the coherence length of the quantum fluctuations rapidly decreases after the wavelength of the perturbation crosses the Hubble radius. Hence, the fluctuations can be interpreted as classical. This lends support to the usual derivation of the spectrum of density perturbations in inflationary Universe models.

QUANTUM COSMOLOGY WITH A NONLINEAR BORN–INFELD TYPE SCALAR FIELD

1999 ◽  
Vol 08 (05) ◽  
pp. 625-634 ◽  
Author(s):  
H. Q. LU ◽  
T. HARKO ◽  
K. S. CHENG
Keyword(s):  
Wave Function ◽  
Scalar Field ◽  
Quantum Cosmology ◽  
Vacuum Energy ◽  
Quantum Model ◽  
Inflationary Universe ◽  
Cosmological Scale ◽  
Scale Factors ◽  
Nonlinear Scalar Field ◽  
The Universe

A quantum model of gravitation interacting with a Born–Infeld type nonlinear scalar field φ is considered. The corresponding Wheeler–DeWitt equation can be solved analytically for both large and small [Formula: see text]. In the extreme limits of small and large cosmological scale factors the wave function of the Universe can also be obtained by applying the methods developed by Vilenkin and Hartle and Hawking. An inflationary Universe is predicted with the largest possible vacuum energy and the largest interaction between the particles of the nonlinear scalar field.

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