Large scale quantum entanglement in de Sitter spacetime

TL;DR

This paper explores quantum entanglement in de Sitter space, demonstrating the existence of multipartite entanglement on superhorizon scales using a harmonic chain model and negativity measures.

Contribution

It introduces a numerical harmonic chain model to analyze quantum entanglement in de Sitter space, revealing entanglement beyond the horizon scale.

Findings

Multipartite entanglement exists on superhorizon scales.

Non-zero logarithmic negativity persists beyond the Hubble horizon.

Entanglement can be detected without coarse-graining in the continuous limit.

Abstract

We investigate quantum entanglement between two symmetric spatialregions in de Sitter space with the Bunch-Davies vacuum. As a discretized model of the scalar field for numerical simulation, we consider a harmonic chain model. Using the coarse-grained variables for the scalar field, it is shown that the multipartite entanglement on the superhorizon scale exists by checking the monogamy relation for the negativity which quantifies the entanglement between the two regions. Further, we consider the continuous limit of this model without coarse-graining and find that non-zero values of the logarithmic negativity exist even if the distance between two spatial regions is larger than the Hubble horizon scale.