# 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} }

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…

## 42 Citations

Initial Condition Problem is Intractable in Cosmology

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- 2019

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…

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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

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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

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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…

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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…

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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…

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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…

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- 2019

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

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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…

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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…

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