scholarly journals Evolution of Inhomogeneities in the Inflationary Universe -No Hair Theorem or Multi-Production of Universes?-

1988 ◽  
Vol 130 ◽  
pp. 67-75
Author(s):  
Katsuhiko Sato
Keyword(s):  
Critical Length ◽  
High Density ◽  
Density Contrast ◽  
Inflationary Universe ◽  
De Sitter ◽  
Inhomogeneous Universe ◽  
Sitter Universe ◽  
De Sitter Universe ◽  
The Universe

Recent investigations on the evolution of the inhomogeneities in the inflationary universe are reviewed. 1) Strict cosmological no hair theorem does not hold, but the class of inhomogeneous universe which evolve to homogeneous de Sitter universe is finite, i.e, “weak cosmic no hair theorem” holds. 2) High density regions in the inhomogeneous universe evolve to wormholes provided that i) the size of the regions is greater than the horizon length, but smaller than a critical length which is the function of the density contrast, and ii) the density is three times higher than that of surrounding region. 3) If wormholes are formed copiously in the period of inflation, they evolve to causally disconnected “child- universes”. In this scenario, the universe we are now observing is one of the locally flat regions.

scholarly journals PHANTOM AND QUANTUM MATTER IN AN ANTI DE SITTER UNIVERSE

2004 ◽  
Vol 19 (01) ◽  
pp. 29-36 ◽  
Author(s):  
EMILIO ElIZALDE ◽  
JOHN QUIROGA HURTADO
Keyword(s):  
Perfect Fluid ◽  
Quantum Effects ◽  
Energy Conditions ◽  
De Sitter ◽  
Quantum Matter ◽  
Trace Anomaly ◽  
Sitter Universe ◽  
De Sitter Universe ◽  
Phantom Matter

We consider an anti de Sitter universe filled by quantum CFT with classical phantom matter and perfect fluid. The model represents the combination of a trace-anomaly annihilated and a phantom driven anti de Sitter universes. The influence exerted by the quantum effects and phantom matter on the AdS space is discussed. Different energy conditions in this type of universe are investigated and compared with those for the corresponding model in a de Sitter universe.

scholarly journals Scalar pair production in a magnetic field in de Sitter universe

2018 ◽  
Vol 78 (5) ◽  
Author(s):  
Mihaela-Andreea Băloi ◽  
Cosmin Crucean ◽  
Diana Popescu
Keyword(s):  
Magnetic Field ◽  
Pair Production ◽  
De Sitter ◽  
Sitter Universe ◽  
De Sitter Universe

scholarly journals Quantum annihilation of Anti-de Sitter universe

2000 ◽  
Vol 475 (3-4) ◽  
pp. 247-252 ◽  
Author(s):  
Iver Brevik ◽  
Sergei D. Odintsov
Keyword(s):  
De Sitter ◽  
Sitter Universe ◽  
De Sitter Universe

scholarly journals Emergent classical universes from initial quantum states in a tomographical description

2020 ◽  
Vol 17 (11) ◽  
pp. 2050167
Author(s):  
Cosimo Stornaiolo
Keyword(s):  
Necessary Conditions ◽  
Phenomenological Approach ◽  
De Sitter ◽  
Present Value ◽  
Asymptotic Expressions ◽  
Classical Transition ◽  
Quantum Tomograms ◽  
De Sitter Universe ◽  
The Universe ◽  
Extract Information

Quantum and classical physical states are represented in a unified way when they aredescribed by symplectic tomography. Therefore this representation allows us to study directly the necessary conditions for a classical universe to emerge from a quantum state. In a previous work on the de Sitter universe this was done by comparing the classical limit of the quantum tomograms with those resulting from the classical cosmological equations. In this paper, we first review these results and extend them to all the de Sitter models. We show further that these tomograms can be obtained directly from transposing the Wheeler–De Witt equation to the tomographic variables. Subsequently, because the classic limits of the quantum tomograms are identified with their asymptotic expressions, we find the necessary conditions to extend the previous results by taking the tomograms of the WKB solutions of the Wheeler–DeWitt equation with an any potential. Furthermore, in the previous works, we found that the de Sitter models undergo the quantum-to-classical transition when the cosmological constant decays to its present value, we discuss at the end how far we can extend this result to more general models. In the conclusions, after discussing any improvements and developments of the results of this work, we sketch a phenomenological approach from which to extract information about the initial states of the universe.

Coupling between time reversal and the space-time symmetries of the de Sitter universe

1974 ◽  
Vol 9 (10) ◽  
pp. 2710-2716 ◽  
Author(s):  
Ronald L. Mallett ◽  
Gordon N. Fleming
Keyword(s):  
Time Reversal ◽  
Space Time ◽  
De Sitter ◽  
Sitter Universe ◽  
De Sitter Universe

Massless particles, conformal group, and de Sitter universe

1981 ◽  
Vol 23 (6) ◽  
pp. 1278-1289 ◽  
Author(s):  
E. Angelopoulos ◽  
M. Flato ◽  
C. Fronsdal ◽  
D. Sternheimer
Keyword(s):  
Conformal Group ◽  
De Sitter ◽  
Massless Particles ◽  
Sitter Universe ◽  
De Sitter Universe
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