QUANTUM COSMOLOGY OF SUPERSTRING UNIVERSE

1991 ◽  
Vol 06 (24) ◽  
pp. 2181-2187
Author(s):  
JIN WANG ◽  
SUBENDRA MOHANTY
Keyword(s):  
Quantum Cosmology ◽  
Bound States ◽  
Classical Model ◽  
Matter Field ◽  
Einstein Equations ◽  
Quantum Model ◽  
Walker Metric ◽  
Discrete Values ◽  
Heating Up ◽  
The Universe

We study the quantum cosmology of the string universe obtained by embedding the Robertson–Walker metric in the nonlinear σ-model.1 We find that the quantum model has some unusual features not seen in the classical model. Initially the universe exists in a series of metastable bound states with scale factor taking discrete values. Then the universe tunnels through a barrier and comes out in an inflationary state. This tunneling (or evolution in imaginary time) also has the effect of heating up the matter field so that we have the conditions of chaotic inflation. Our asymptotic solutions agree with those obtained from the classical Einstein equations in Ref. 1.

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.

scholarly journals VIOLATION OF STRONG ENERGY CONDITION IN EFFECTIVE LOOP QUANTUM COSMOLOGY

2007 ◽  
Vol 22 (18) ◽  
pp. 3137-3146 ◽  
Author(s):  
HUA-HUI XIONG ◽  
JIAN-YANG ZHU
Keyword(s):  
Quantum Cosmology ◽  
Small Volume ◽  
Energy Condition ◽  
Matter Field ◽  
Loop Quantum Cosmology ◽  
Quantum Geometry ◽  
Strong Energy Condition ◽  
Strong Energy ◽  
Scalar Matter ◽  
The Universe

In loop quantum cosmology nonperturbative modification to a scalar matter field at short scales implies inflation which also means a violation of the strong energy condition. In the framework of effective Hamiltonian we discuss the issue of violation of the strong energy condition in the presence of quantum geometry potential. It is shown that the appearance of quantum geometry potential strengthens the violation of the strong energy condition in small volume regions. In the small volume regions superinflation can easily happen. Furthermore, when the evolution of the universe approaches the bounce scale, this trend of violating the strong energy condition can be greatly amplified.

scholarly journals Quantum Cosmology in the Light of Quantum Mechanics

Galaxies ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 50
Author(s):  
Salvador J. Robles-Pérez
Keyword(s):  
Wave Function ◽  
Quantum Mechanics ◽  
Quantum State ◽  
Test Particle ◽  
Quantum Cosmology ◽  
Matter Field ◽  
Starting Point ◽  
The Universe ◽  
Semiclassical State ◽  
Matter Fields

There is a formal analogy between the evolution of the universe, when it is seen as a trajectory in the minisuperspace, and the worldline followed by a test particle in a curved spacetime. The analogy can be extended to the quantum realm, where the trajectories are transformed into wave packets that give us the probability of finding the universe or the particle in a given point of their respective spaces: the spacetime in the case of the particle and the minisuperspace in the case of the universe. The wave function of the spacetime and the matter fields, all together, can then be seen as a super-field that propagates in the minisuperspace and the so-called third quantisation procedure can be applied in a parallel way as the second quantisation procedure is performed with a matter field that propagates in the spacetime. The super-field can thus be interpreted as made up of universes propagating, i.e., evolving, in the minisuperspace. The analogy can also be used in the opposite direction. The way in which the semiclassical state of the universe is obtained in quantum cosmology allows us to obtain, from the quantum state of a field that propagates in the spacetime, the geodesics of the underlying spacetime as well as their quantum uncertainties or dispersions. This might settle a new starting point for a different quantisation of the spacetime.

scholarly journals Quantum Cosmology in the Light of Quantum Mechanics

2019 ◽  
Author(s):  
Salvador Robles-Perez
Keyword(s):  
Wave Function ◽  
Quantum Mechanics ◽  
Quantum State ◽  
Test Particle ◽  
Quantum Cosmology ◽  
Matter Field ◽  
Starting Point ◽  
The Universe ◽  
Semiclassical State ◽  
Matter Fields

There is a formal analogy between the evolution of the universe, when this is seen as a trajectory in the minisuperspace, and the worldline followed by a test particle in a curved spacetime. The analogy can be extended to the quantum realm, where the trajectories are transformed into wave packets that give us the probability of finding the universe or the particle in a given point of their respective spaces: the spacetime in the case of the particle and the minisuperspace in the case of the universe. The wave function of the spacetime and the matter fields, all together, can then be seen as a super-field that propagates in the minisuperspace and the so-called third quantisation procedure can be applied in a parallel way as the second quantisation procedure is performed with a matter field that propagates in the spacetime. The super-field can thus be interpreted as made up of universes propagating, i.e. evolving, in the minisuperspace. The analogy can also be used in the opposite direction. The way in which the semiclassical state of the universe is obtained in quantum cosmology allows us to obtain, from the quantum state of a field that propagates in the spacetime, the geodesics of the underlying spacetime as well as their quantum uncertainties or dispersions. This might settle a new starting point for a different quantisation of the spacetime.

scholarly journals Wave Packet in Quantum Cosmology and Definition of Semiclassical Time

1997 ◽  
Vol 12 (05) ◽  
pp. 859-871
Author(s):  
Y. Ohkuwa ◽  
T. Kitazoe
Keyword(s):  
Wave Function ◽  
Scalar Field ◽  
Wave Packet ◽  
Quantum Cosmology ◽  
Matter Field ◽  
Time Variable ◽  
Wave Functions ◽  
Quantum Matter ◽  
Definition Of ◽  
The Universe

We consider a quantum cosmology with a massless background scalar field ϕB and adopt a wave packet as the wave function. This wave packet is a superposition of the WKB form wave functions, each of which has a definite momentum of the scalar field ϕB. In this model it is shown that to trace the formalism of the WKB time is seriously difficult without introducing a complex value for a time. We define a semiclassical real time variable TP from the phase of the wave packet and calculate it explicitly. We find that, when a quantum matter field ϕQ is coupled to the system, an approximate Schrödinger equation for ϕQ holds with respect to TP in a region where the size a of the universe is large and |ϕB| is small.

scholarly journals Quantum Computer: Quantum Model and Reality

2020 ◽  
Author(s):  
Vasil Dinev Penchev
Keyword(s):  
Quantum Mechanics ◽  
Turing Machine ◽  
Quantum Computer ◽  
Classical Model ◽  
Hidden Variables ◽  
Quantum Model ◽  
Computational Process ◽  
Intermediate Domain ◽  
And Mathematics ◽  
The Axiom Of Choice

Any computer can create a model of reality. The hypothesis that quantum computer can generate such a model designated as quantum, which coincides with the modeled reality, is discussed. Its reasons are the theorems about the absence of “hidden variables” in quantum mechanics. The quantum modeling requires the axiom of choice. The following conclusions are deduced from the hypothesis. A quantum model unlike a classical model can coincide with reality. Reality can be interpreted as a quantum computer. The physical processes represent computations of the quantum computer. Quantum information is the real fundament of the world. The conception of quantum computer unifies physics and mathematics and thus the material and the ideal world. Quantum computer is a non-Turing machine in principle. Any quantum computing can be interpreted as an infinite classical computational process of a Turing machine. Quantum computer introduces the notion of “actually infinite computational process”. The discussed hypothesis is consistent with all quantum mechanics. The conclusions address a form of neo-Pythagoreanism: Unifying the mathematical and physical, quantum computer is situated in an intermediate domain of their mutual transformations.

Yoga and The Physics of Higher States of Consciousness

2018 ◽  
pp. 335-358
Author(s):  
Alex Hankey
Keyword(s):  
Quantum Cosmology ◽  
Sense Perception ◽  
Pure Consciousness ◽  
States Of Consciousness ◽  
Action Refinement ◽  
Higher States Of Consciousness ◽  
Modern Physics ◽  
Inner Light ◽  
The Universe

Higher states of consciousness are developed by meditation, defined by Patanjali as that which transforms focused attention into pure consciousness, the 4th state of pure consciousness - a major state in its own right, with its own physics, that of ‘experience information'. Phenomenologies of states 5 to 7 are explained from the perspective of modern physics and quantum cosmology. The role of the 5th state in life is to make possible witnessing states 1 to 3 resulting in ‘Perfection in Action'. Refinement of perception involved in the 6th State results in hearing the Cosmic Om, seeing the Inner Light, and seventh sense perception. All require special amplification processes on pathways of perception. Unity and Brahman Consciousness and their development are discussed with examples from the great sayings of the Upanishads, and similar cognitions like those of poet, Thomas Traherne. Throughout, supporting physics is given, particularly that of experience information, and its implications for Schrodinger's cat paradox and our scientific understanding of the universe as a whole.

Tomographic analysis of quantum and classical de Sitter cosmological models

2019 ◽  
Vol 28 (16) ◽  
pp. 2040009 ◽  
Author(s):  
Cosimo Stornaiolo
Keyword(s):  
Quantum Cosmology ◽  
Classical Limit ◽  
Initial Conditions ◽  
Quantum Tomography ◽  
Wave Functions ◽  
Hamiltonian Constraint ◽  
De Sitter ◽  
Quantum Universe ◽  
Tomographic Analysis ◽  
The Universe

In this work, we show the importance of introducing the quantum tomography formalism to analyze the properties of wave functions in quantum cosmology. In particular, we examine the initial conditions of the universe proposed by various authors in the context of de Sitter’s cosmology studying their classical limit and comparing it with the classical tomogram obtained from the Hamiltonian constraint in General Relativity. This comparison gives us the opportunity to find under which conditions there is a transition from the quantum universe to the classical one. A relevant result is that in these models the decay of the cosmological constant is a sufficient condition for this transition.

COSMIC TIME IN QUANTUM COSMOLOGY: INFLATION-COMPACTIFICATION AS A QUANTUM EFFECT

1993 ◽  
Vol 02 (02) ◽  
pp. 221-247 ◽  
Author(s):  
E.I. GUENDELMAN ◽  
A.B. KAGANOVICH
Keyword(s):  
Cosmological Constant ◽  
Quantum Cosmology ◽  
Quantum Effect ◽  
Cosmic Time ◽  
Expectation Values ◽  
Cosmological Singularity ◽  
Inflationary Phase ◽  
Definition Of ◽  
The Universe ◽  
Kaluza Klein

We consider 1+D-dimensional, toroidally compact Kaluza-Klein theories. In the context of the minisuperspace approach of quantum cosmology, we solve the Wheeler-DeWitt equation in the presence of a negative cosmological constant and dust. Then, it is found that the quantum effects stabilize the volume of the Universe, so that there can be an avoidance of the cosmological singularity. Although cosmic time does not appear explicitly in the Wheeler-DeWitt equation, we find that a cosmic time dependence appears for the expectation values of certain variables. This result is obtained when proper care of some subtle points concerning the definition of averages in this model is taken. The stabilization of the volume, when there is anisotropy in the evolution of the Universe (which turns out to be quantized), is consistent with another effect we find: the existence of a “quantum inflationary phase” for some dimensions and simultaneously the existence of a “quantum deflationary contraction” for the rest.

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