scholarly journals Dust fluid component from Lie symmetries in scalar field cosmology

2017 ◽  
Vol 32 (37) ◽  
pp. 1750206 ◽  
Author(s):  
Andronikos Paliathanasis
Keyword(s):  
Wave Function ◽  
Scalar Field ◽  
Energy Density ◽  
Lie Symmetries ◽  
Quantum Corrections ◽  
Fluid Component ◽  
Dust Fluid ◽  
Scalar Field Cosmology

We show that in scalar field cosmology, a dust fluid follows as quantum corrections from solutions of the Wheeler–DeWitt equation generated by Lie symmetries. The energy density of the dust fluid is related with the frequency of the wave function.

A new look at the Schrödinger equation in exact scalar field cosmology

2019 ◽  
Vol 16 (02) ◽  
pp. 1950022 ◽  
Author(s):  
I. V. Fomin ◽  
S. V. Chervon ◽  
S. D. Maharaj
Keyword(s):  
Wave Function ◽  
Scalar Field ◽  
Exact Solutions ◽  
Closed Form ◽  
Generating Function ◽  
Hubble Parameter ◽  
Scalar Potential ◽  
Scale Factor ◽  
Simple Transformation ◽  
Scalar Field Cosmology

We propose a new representation of the Schrödinger-like equation for scalar field Friedmann cosmology where the scalar field is the argument, and the Hubble parameter is the analogue to the wave function. Such an approach gives us the possibility to use the Schrödinger potential as a generating function which leads to generalization of known exact solutions. Further, we find a simple transformation of the Hubble parameter which generates new solutions from the Schrödinger-like equation. Several examples are identified where exact forms for the scale factor, Hubble parameter and scalar potential can be written in closed form. Earlier results are regained in our approach.

scholarly journals Wheeler–DeWitt equation and Lie symmetries in Bianchi scalar-field cosmology

2016 ◽  
Vol 76 (4) ◽  
Author(s):  
A. Paliathanasis ◽  
L. Karpathopoulos ◽  
A. Wojnar ◽  
S. Capozziello
Keyword(s):  
Scalar Field ◽  
Lie Symmetries ◽  
Scalar Field Cosmology

scholarly journals Quantum corrections to slow-roll inflation: scalar and tensor modes

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Jens O. Andersen ◽  
Magdalena Eriksson ◽  
Anders Tranberg
Keyword(s):  
Scalar Field ◽  
Quantum Corrections ◽  
Tree Level ◽  
Field Equations ◽  
Slow Roll ◽  
Scalar Field Equations ◽  
Slow Rolling ◽  
Different Sources ◽  
Suitable Potential ◽  
Quadratic Order

Abstract Inflation is often described through the dynamics of a scalar field, slow-rolling in a suitable potential. Ultimately, this inflaton must be identified with the expectation value of a quantum field, evolving in a quantum effective potential. The shape of this potential is determined by the underlying tree-level potential, dressed by quantum corrections from the scalar field itself and the metric perturbations. Following [1], we compute the effective scalar field equations and the corrected Friedmann equations to quadratic order in both scalar field, scalar metric and tensor perturbations. We identify the quantum corrections from different sources at leading order in slow-roll, and estimate their magnitude in benchmark models of inflation. We comment on the implications of non-minimal coupling to gravity in this context.

The dynamical system approach to scalar field cosmology

2000 ◽  
Vol 17 (8) ◽  
pp. 1783-1814 ◽  
Author(s):  
E Gunzig ◽  
V Faraoni ◽  
A Figueiredo ◽  
T M Rocha Filho ◽  
L Brenig
Keyword(s):  
Dynamical System ◽  
Scalar Field ◽  
System Approach ◽  
Dynamical System Approach ◽  
Scalar Field Cosmology

scholarly journals Noncommutativity and scalar field cosmology

2007 ◽  
Vol 76 (8) ◽  
Author(s):  
W. Guzmán ◽  
M. Sabido ◽  
J. Socorro
Keyword(s):  
Scalar Field ◽  
Scalar Field Cosmology

scholarly journals Quantization of Einstein-aether scalar field cosmology

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
N. Dimakis ◽  
T. Pailas ◽  
A. Paliathanasis ◽  
G. Leon ◽  
Petros A. Terzis ◽  
...  
Keyword(s):  
Scalar Field ◽  
Classical Solution ◽  
Potential Function ◽  
Scalar Fields ◽  
Inflationary Model ◽  
Cosmological Theory ◽  
Local Functions ◽  
Arbitrary Potential ◽  
Scalar Field Cosmology ◽  
First Time

AbstractWe present, for the first time, the quantization process for the Einstein-aether scalar field cosmology. We consider a cosmological theory proposed as a Lorentz violating inflationary model, where the aether and scalar fields interact through the assumption that the aether action constants are ultra-local functions of the scalar field. For this specific theory there is a valid minisuperspace description which we use to quantize. For a particular relation between the two free functions entering the reduced Lagrangian the solution to the Wheeler–DeWitt equation as also the generic classical solution are presented for any given arbitrary potential function.

scholarly journals Modern Topics in Scalar Field Cosmology

2020 ◽  
Author(s):  
◽  
Cari Powell
Keyword(s):  
Dark Matter ◽  
Scalar Field ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Mass Range ◽  
Distant Future ◽  
Field System ◽  
Stochastic Background ◽  
Scalar Field Cosmology

The aim of this research is to use modern techniques in scalar field Cosmol-ogy to produce methods of detecting gravitational waves and apply them to current gravitational waves experiments and those that will be producing results in the not too distant future. In the first chapter we discuss dark matter and some of its candidates, specifically, the axion. We then address its relationship with gravitational waves. We also discuss inflation and how it can be used to detect gravitational waves. Chapter 2 concentrates on constructing a multi field system of axions in order to increase the mass range of the ultralight axion, putting it into the observation range of pul-sar timing arrays. Chapter 3 discusses non-attractor inflation which is able to enhance stochastic background gravitational waves at scales that allows them to be measured by gravitational wave experiments. Chapter 4 uses a similar method to chapter 3 and applies it to 3-point overlap functions for tensor, scalar and a combination of the two polarisations.

scholarly journals Scalar field cosmology in Lyra's geometry

2015 ◽  
Vol 3 (2) ◽  
pp. 117 ◽  
Author(s):  
V. K. Shchigolev ◽  
E. A. Semenova
Keyword(s):  
Exact Solution ◽  
Scalar Field ◽  
Generating Function ◽  
Function Method ◽  
Scalar Fields ◽  
First Order ◽  
Homogeneous Cosmological Models ◽  
Different Types ◽  
Lyra’S Geometry ◽  
Scalar Field Cosmology

<p>The new classes of homogeneous cosmological models for the scalar fields are build in the context of Lyra’s geometry. The different types of exact solution for the model are obtained by applying two procedures, viz the generating function method and the first order formalism.</p>

scholarly journals SPECTRA OF RELIC GRAVITONS AND BRANS–DICKE THEORY

2005 ◽  
Vol 20 (02) ◽  
pp. 127-134 ◽  
Author(s):  
B. K. SAHOO
Keyword(s):  
Scalar Field ◽  
Energy Density ◽  
Time Dependence ◽  
Gravitational Waves ◽  
Hubble Parameter ◽  
Frequency Dependent ◽  
Cosmological Expansion ◽  
Relic Gravitational Waves ◽  
Matter Energy ◽  
Inflationary Models

The spectra of relic gravitational waves produced as a result of cosmological expansion of the inflationary models are derived in Brans–Dicke (BD) theory of gravity. The time dependence of the very early Hubble parameter and matter energy density are derived from frequency-dependent spectrum of relic gravitational waves. Also it is found that Brans–Dicke scalar field contributes to the energy density of relic gravitons.

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