Time and Entropy from Semi-classical Tunneling of the Cosmological Scale Function

TL;DR

This paper explores how semi-classical tunneling in cosmology links the emergence of time and entropy in de Sitter models, revealing a unified physical mechanism involving quantum-gravity and matter state mixing.

Contribution

It demonstrates that the origin of time and entropy in cosmology can be explained by a single tunneling phenomenon affecting quantum matter and semi-classical gravity.

Findings

Tunneling causes mixing of quantum matter and gravity states.

This mixing leads to entropy in de Sitter models.

The same process converts parametric time into intrinsic physical time.

Abstract

Two major apparently unrelated problems, that of the origin of time in the universe associated with quantum gravity and to the entropy in de Sitter cosmological models, are found to have their origin in a single physical phenomenon: the semi-classical tunneling through a classically forbidden region of the cosmological scale function. In this region there is a mixing of the states of quantum matter and those of the semi-classical gravity which produces a thermal mixture of the matter states and hence an "entropy"; this same mixing effect brings about the conversion of a parametric time variable into a physical intrinsic time.