Universal role of curvature in vacuum entanglement

TL;DR

This paper investigates how spacetime curvature universally influences entanglement between quantum probes in vacuum, revealing conditions where curvature induces entanglement, thus enabling entanglement to serve as a probe of spacetime geometry.

Contribution

It introduces a universal analysis of curvature effects on vacuum entanglement, including numerical results in de Sitter spacetime and exploration of strong curvature regimes.

Findings

Curvature can induce entanglement in initially unentangled probes.

Entanglement features depend on parameters like energy gap, separation, and velocity.

Results suggest entanglement can be used to probe spacetime curvature.

Abstract

We highlight some universal features concerning the role of spacetime curvature in the entanglement induced between quantum probes coupled to a quantum field in a suitable vacuum state. The probes are initially causally disconnected and non-entangled. We explore the parameter space $\{{\omega}, d_0, \boldsymbol{v}_0\}$ spanned by the energy gap $\omega$ of the detectors, and the initial values of separation distance $d_0$ and relative velocity $\boldsymbol{v}_0$, both covariantly defined in arbitrary curved spacetime. We also obtain numerical results in de Sitter spacetimes and use these to explore strong curvature regime, while also corroborating our perturbative results in arbitrary curved spacetime. Our analysis shows that curvature can induce entanglement features in certain regions of the above parameter space, in a manner which facilitates using entanglement as a probe of spacetime curvature.