Essay: Initial Conditions for a Universe

@article{Bojowald2003EssayIC,
  title={Essay: Initial Conditions for a Universe},
  author={Martin Bojowald},
  journal={General Relativity and Gravitation},
  year={2003},
  volume={35},
  pages={1877-1883}
}
  • M. Bojowald
  • Published 19 May 2003
  • Physics
  • General Relativity and Gravitation
In physical theories, boundary or initial conditions play the role of selecting special situations which can be described by a theory with its general laws. Cosmology has long been suspected to be different in that its fundamental theory should explain the fact that we can observe only one particular realization. This is not realized, however, in the classical formulation and in its conventional quantization; the situation is even worse due to the singularity problem. In recent years, a new… 
Initial Condition Problem is Intractable in Cosmology
Determining the initial state of the universe is a challenging problem in quantum cosmology and we argue that the issue is intractable if the basic postulates of quantum mechanics are not modified in
QUANTUM GEOMETRY AND ITS IMPLICATIONS FOR BLACK HOLES
General relativity successfully describes space–times at scales that we can observe and probe today, but it cannot be complete as a consequence of singularity theorems. For a long time, there have
Loop Quantum Cosmology and Boundary Proposals
For many years, the most active area of quantum cosmology has been the issue of choosing boundary conditions for the wave function of a universe. Recently, loop quantum cosmology, which is obtained
Elements of Loop Quantum Cosmology
The expansion of our universe, when followed backward in time, implies that it emerged from a phase of huge density, the big bang. These stages are so extreme that classical general relativity
Universe scenarios from loop quantum cosmology
Loop quantum cosmology is an application of recent developments for a non-perturbative and background independent quantization of gravity to a cosmological setting. Characteristic properties of the
Loop quantum cosmology: Recent progress
Aspects of the full theory of loop quantum gravity can be studied in a simpler context by reducing to symmetric models like cosmological ones. This leads to several applications where loop effects
Space-Time Extensions in Quantum Gravity
Space-time as described by special and general relativity is a classical object. In general relativity, it becomes dynamical, participates in the interactions between all degrees of freedom and can
Initial wave function of the universe is arbitrary
We consider quantization of the gravity-scalar field system in the minisuperspace approximation. It turns out that in the gauge fixed deparametrized theory where the scale factor plays the role of
Chapter 8 Space-Time Extensions in Quantum Gravity
Space-time as described by special and general relativity is a classical object. In general relativity, it becomes dynamical, participates in the interactions between all degrees of freedom and can
Canonical Relativity and the Dimensionality of the World
Different aspects of relativity, mainly in a canonical formulation, relevant for the question “Is spacetime nothing more than a mathematical space (which describes the evolution in time of the
...
1
2
3
4
5
...

References

SHOWING 1-10 OF 10 REFERENCES
Absence of a singularity in loop quantum cosmology.
  • M. Bojowald
  • Physics, Medicine
    Physical review letters
  • 2001
TLDR
It is shown that the cosmological singularity in isotropic minisuperspaces is naturally removed by quantum geometry and the correct semiclassical behavior is obtained.
Isotropic loop quantum cosmology
Isotropic models in loop quantum cosmology allow explicit calculations, thanks largely to a completely known volume spectrum, which is exploited in order to write down the evolution equation in a
Quantum Theory of Gravity. I. The Canonical Theory
Following an historical introduction, the conventional canonical formulation of general relativity theory is presented. The canonical Lagrangian is expressed in terms of the extrinsic and intrinsic
Introduction to Modern Canonical Quantum General Relativity
This is an introduction to the by now fifteen years old research field of canonical quantum general relativity, sometimes called "loop quantum gravity". The term "modern" in the title refers to the
Inverse scale factor in isotropic quantum geometry
The inverse scale factor, which in classical cosmological models diverges at the singularity, is quantized in isotropic models of loop quantum cosmology by using techniques which have been developed
Wave Function of the Universe
TLDR
A proposal for the wave function of the "ground state" or state of minimum excitation: the ground-state amplitude for a three-geometry is given by a path integral over all compact positive-definite four-geometries which have the three- geometries as a boundary.
Quantum cosmology as an initial value problem
Abstract The Wheeler-DeWitt equation for a closed Friedmann universe allows one to impose an (intrinsic) symmetric initial condition (SIC!) at the “big brunch” (superposition of big bang and big
Dynamical initial conditions in quantum cosmology.
  • M. Bojowald
  • Physics, Medicine
    Physical review letters
  • 2001
TLDR
Loop quantum cosmology is shown to provide both the dynamical law and initial conditions for the wave function of a universe by one discrete evolution equation and a unique wave function is predicted.
What is Quantum Theory of Gravity
We present a line by line derivation of canonical quantum mechanics stemming from the compatibility of the statistical geometry of distinguishable observations with the canonical Poisson structure of
Quantum Creation of Universes
A cosmological wave function describing the tunneling of the Universe from "nothing" into a de Sitter space is found in a simple minisuperspace model. The tunneling probability is proportional to