Extraction of timelike entanglement from the quantum vacuum

TL;DR

This paper demonstrates that timelike entanglement present in the quantum vacuum can be extracted and converted into usable entanglement between two detectors at the same location but different times, revealing time correlations in quantum fields.

Contribution

It introduces a method to extract timelike entanglement from the quantum vacuum and convert it into standard entanglement between detectors, highlighting the role of time correlations.

Findings

Timelike entanglement exists in the quantum vacuum.

Extraction requires precise timing between detectors.

Extracted entanglement can be converted into usable quantum correlations.

Abstract

Recently, it has been shown that the massless quantum vacuum state contains entanglement between timelike separated regions of spacetime, in addition to the entanglement between the spacelike separated regions usually considered. Here, we show that timelike entanglement can be extracted from the Minkowski vacuum and converted into ordinary entanglement between two inertial, two-state detectors at the same spatial location -- one coupled to the field in the past and the other coupled to the field in the future. The procedure used here demonstrates a clear time correlation as a requirement for extraction, e.g. if the past detector was active at a quarter to 12:00, then the future detector must wait to become active at precisely a quarter past 12:00 in order to achieve entanglement.