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.

scholarly journals QUANTUM FLUCTUATIONS FOR A SCALAR FIELD IN THE SPACE–TIME OF GRAVITATIONAL IMPLUSIVE WAVE

1998 ◽  
Vol 13 (08) ◽  
pp. 1201-1211 ◽  
Author(s):  
Y. ENGINER ◽  
M. HORTAÇSU ◽  
N. ÖZDEMIR
Keyword(s):  
Scalar Field ◽  
Gravitational Waves ◽  
Quantum Fluctuations ◽  
De Sitter Space ◽  
Space Time ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
De Sitter

Quantum fluctuations for a massless scalar field in the background metric of spherical implusive gravitational waves propagating through Minkowski and de Sitter spaces are investigated. It is shown that there exist finite fluctuations for de Sitter space.

scholarly journals The Effect of de-Sitter Like Background on Increasing the Zero Point Budget of Dark Energy

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Haidar Sheikhahmadi ◽  
Ali Aghamohammadi ◽  
Khaled Saaidi
Keyword(s):  
Scalar Field ◽  
Energy Density ◽  
Quantum Fluctuations ◽  
Zero Point ◽  
Scalar Fields ◽  
Massless Scalar Field ◽  
De Sitter ◽  
Data Set ◽  
Massive Scalar Field ◽  
The Universe

During this work, using subtraction renormalization mechanism, zero point quantum fluctuations for bosonic scalar fields in a de-Sitter like background are investigated. By virtue of the observed value for spectral index,ns(k), for massive scalar field the best value for the first slow roll parameter,ϵ, is achieved. In addition, the energy density of vacuum quantum fluctuations for massless scalar field is obtained. The effects of these fluctuations on other components of the universe are studied. By solving the conservation equation, for some different examples, the energy density for different components of the universe is obtained. In the case which all components of the universe are in an interaction, the different dissipation functions,Q~i, are considered. The time evolution ofρDE(z)/ρcri(z)shows thatQ~=3γH(t)ρmhas the best agreement in comparison to observational data including CMB, BAO, and SNeIa data set.

STOCHASTIC DYNAMICS OF SCALAR FIELD IN THE INFLATIONARY UNIVERSE

1989 ◽  
Vol 04 (10) ◽  
pp. 2613-2625 ◽  
Author(s):  
AKIO HOSOYA ◽  
MASAHIRO MORIKAWA ◽  
KEIJI NAKAYAMA
Keyword(s):  
Langevin Equation ◽  
Stochastic Dynamics ◽  
Momentum Tensor ◽  
Inflationary Universe ◽  
De Sitter ◽  
Tensor Correlation ◽  
Long Wavelength ◽  
Statistical Correlations ◽  
Effective Dynamics ◽  
Density Perturbations

An effective dynamics of a long wavelength part of an inflation in de Sitter space is derived in the form of the Langevin equation by regarding the remaining short wavelength part as a noise. Classical properties of the noise and the long wavelength part are investigated and their statistical correlations are derived. The formulation is applied to the generation of density perturbations. Here the interaction in the Langevin equation is shown to be indispensable as far as we disregard the singular contribution of the energy-momentum tensor correlation.

PARTICLE PRODUCTION DURING INFLATIONARY REHEATING

1992 ◽  
Vol 07 (09) ◽  
pp. 2033-2044 ◽  
Author(s):  
M. BASLER ◽  
B. KÄMPFER
Keyword(s):  
Scalar Field ◽  
Particle Production ◽  
Field Model ◽  
Particle Creation ◽  
Background Field ◽  
Time Development ◽  
Parameter Dependence ◽  
Inflationary Universe ◽  
Numerical Investigations ◽  
Universe Models

A possible reheating mechanism in inflationary universe models is studied in some detail. Results are presented of numerical investigations of particle creation and corresponding reheating within a self-coupled scalar field model. By using the method of Hamiltonian diagonalization attention is devoted to the time development of the process and its parameter dependence. The effect of particle production is found to depend strongly on the anharmonicity of the potential around its minimum and on the amplitude of the oscillations of the scalar background field.

scholarly journals CLOSED INFLATIONARY UNIVERSE MODELS IN BRANE WORLD COSMOLOGY

2005 ◽  
Vol 14 (05) ◽  
pp. 861-872 ◽  
Author(s):  
SERGIO DEL CAMPO ◽  
RAMÓN HERRERA ◽  
JOEL SAAVEDRA
Keyword(s):  
General Relativity ◽  
Scalar Field ◽  
Brane World ◽  
Inflationary Universe ◽  
Closed Universe ◽  
Cosmological Context ◽  
The One ◽  
Universe Models ◽  
Einstein’S General Relativity

In this article we study closed inflationary universe models proposed by Linde in a brane world cosmological context. In this scenario we determine and characterize the existence of a closed universe, in presence of one self-interacting scalar field with an inflationary stage. We have found that our model, which takes into account a Brane World Cosmology, is less restrictive than the one that uses standard Einstein's General Relativity cosmology.

scholarly journals EFFECTS OF BLACK HOLES ON INFLATON PERTURBATION

2012 ◽  
Vol 12 ◽  
pp. 272-279
Author(s):  
HING-TONG CHO ◽  
KIN-WANG NG ◽  
I-CHIN WANG
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Field ◽  
Power Spectrum ◽  
Perturbation Approach ◽  
Inflationary Universe ◽  
Cosmological Horizon ◽  
De Sitter ◽  
Small Black Hole ◽  
Free Scalar

We calculate quantum fluctuations of a free scalar field in the Schwarzschild-de Sitter space-time, adopting the planar coordinates that is pertinent to the presence of a black hole in an inflationary universe. In a perturbation approach, doing expansion in powers of a small black hole event horizon compared to the de Sitter cosmological horizon, we obtain the scalar power spectrum.

scholarly journals WARM-POLYTROPIC INFLATIONARY UNIVERSE MODEL

2013 ◽  
Vol 22 (08) ◽  
pp. 1350041 ◽  
Author(s):  
M. R. SETARE ◽  
M. J. S. HOUNDJO ◽  
V. KAMALI
Keyword(s):  
Exact Solution ◽  
Scalar Field ◽  
Hubble Parameter ◽  
Inflationary Universe ◽  
Universe Model ◽  
Polytropic Gas ◽  
Slow Roll ◽  
Universe Models ◽  
Explicit Expressions

In this paper, we study warm inflationary universe models in the context of a polytropic gas. We derive the characteristics of this model in slow-roll approximation and develop our model in two cases: (1) for a constant dissipative parameter Γ; (2) Γ as a function of scalar field ϕ. In these cases, we will obtain exact solution for the scalar field and Hubble parameter. We will also obtain explicit expressions for the tensor-scalar ratio R, scalar spectrum index ns and its running αs in slow-roll approximation.

scholarly journals LRS Bianchi Type II Inflationary Universe with Massless Scalar Field

2011 ◽  
Vol 2011 ◽  
pp. 1-3 ◽  
Author(s):  
Raj Bali ◽  
Laxmi Poonia
Keyword(s):  
Scalar Field ◽  
Bianchi Type ◽  
Cosmic Time ◽  
Accelerating Universe ◽  
Massless Scalar ◽  
Inflationary Universe ◽  
Massless Scalar Field ◽  
Type Ii ◽  
De Sitter ◽  
Deterministic Solution

Inflationary scenario in locally rotationally symmetric (LRS) Bianchi Type II space-time with massless scalar field with flat potential is discussed. To get the deterministic solution in terms of cosmic time , we have assumed that the scale factor , that is, and  = constant where is effective potential and is Higg's field. We find that spatial volume increases with time and the model isotropizes for large value of under special condition. The Higg's field decreases slowly and tends to a constant value when . The model represents uniform expansion but accelerating universe and leads to de-Sitter type metric.

scholarly journals Thermodynamics of de Sitter black holes with a conformally coupled scalar field

2005 ◽  
Vol 72 (2) ◽  
Author(s):  
Anne-Marie Barlow ◽  
Daniel Doherty ◽  
Elizabeth Winstanley
Keyword(s):  
Black Holes ◽  
Scalar Field ◽  
De Sitter
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