The (A)temporal Emergence of Spacetime

TL;DR

This paper explores how quantum gravity models from string theory and loop quantum gravity address the big bang, focusing on the emergence of spacetime from non-spatiotemporal quantum regions and their conceptual implications.

Contribution

It analyzes the transition from non-spatiotemporal quantum regions to classical spacetime, highlighting foundational issues and conceptual challenges in quantum cosmology.

Findings

Classical singularity is replaced by quantum regions.

Transitions may occur without a well-defined notion of time.

Discussion of empirical incoherence in non-spatiotemporal phases.

Abstract

This paper examines two cosmological models of quantum gravity (from string theory and loop quantum gravity) to investigate the foundational and conceptual issues arising from quantum treatments of the big bang. While the classical singularity is erased, the quantum evolution that replaces it may not correspond to classical spacetime: it may instead be a non-spatiotemporal region, which somehow transitions to a spatiotemporal state. The different kinds of transition involved are partially characterized, the concept of a physical transition without time is investigated, and the problem of empirical incoherence for regions without spacetime is discussed.