Time as a Consequence of Internal Coherence

TL;DR

This paper explores how internal quantum coherence underpins the emergence of time in the Page-Wootters mechanism, linking it to quantum thermodynamics and the extractable work from coherence.

Contribution

It introduces a measure of internal coherence that explains the relational emergence of time and connects it to quantum thermodynamics.

Findings

Internal coherence is necessary for the emergence of time.

The measure relates to the extractable work from quantum coherence.

Time arises from correlations in quantum states.

Abstract

Time has been an elusive concept to grasp. Although we do not yet understand it properly, there has been advances made in regards to how we can explain it. One such advance is the Page-Wootters mechanism. In this mechanism time is seen as an inaccessible coordinate and the apparently passage of time arises as a consequence of correlations between the subsystems of a global state. Here we propose a measure that captures the relational character of the mechanism, showing that the internal coherence is the necessary ingredient for the emergence of time in the Page-Wootters model. Also, we connect it to results in quantum thermodynamics, showing that it is directly related to the extractable work from quantum coherence.