Singularities in a Scalar Field Quantum Cosmology

TL;DR

This paper investigates a quantum cosmological model with a scalar field, demonstrating that quantum effects can remove classical singularities and challenge previous assumptions about the nature of singularities in quantum cosmology.

Contribution

It shows that in a quantum scalar field cosmology, classical singularities are resolved, providing new insights into the quantum nature of the universe's evolution.

Findings

Quantum model is nonsingular where classical is singular

Quantum effects can eliminate classical cosmological singularities

Disproves the conjecture that quantum singularities are predetermined by classical choices

Abstract

The quantum theory of a spatially flat Friedmann-Robertson-Walker universe with a massless scalar field as source is further investigated. The classical model is singular, and in the framework of the Arnowitt-Deser-Misner canonical quantization formalism a discussion is made of the cosmic evolution, particularly of the quantum gravitational collapse problem. It is shown that in a matter-time gauge such that time is identified with the scalar field the classical model is singular either at $t=-\infty$ or at $t=+\infty$, but the quantum model is nonsingular. The latter behavior disproves a conjecture according to which quantum cosmological singularities are predetermined on the classical level by the choice of time.