Quantum Cosmology

TL;DR

Quantum cosmology applies quantum physics to the entire universe, exploring conceptual issues like singularity resolution and initial conditions, with various approaches primarily based on canonical quantization.

Contribution

This paper reviews the scope, approaches, and conceptual applications of quantum cosmology, highlighting its relation to quantum gravity and the Wheeler--DeWitt equation.

Findings

Potential resolution of classical singularities

Insights into the universe's initial conditions

Exploration of quantum origins of classical world

Abstract

Quantum cosmology in general denotes the application of quantum physics to the whole universe and thus gives rise to many realizations and examples, covering problems at different mathematical and conceptual levels. It is related to quantum gravity and more specifically describes the application to cosmological situations rather than the construction and analysis of quantum field equations. As there are several different approaches to quantum gravity, equations for quantum cosmology are not unique. Most investigations have been performed in the context of canonical quantization, where Wheeler--DeWitt like equations are the prime object. Applications are mostly conceptual, ranging from possible resolutions of classical singularities and explanations of the uniqueness of the universe to the origin of seeds for a classical world and its initial conditions.