Characterization of quantum and classical correlations in the Earth curved space-time

TL;DR

This paper analyzes how Earth's curved space-time, modeled by the Kerr metric, influences quantum and classical correlations in photon pairs, revealing that gravitational effects cause measurable changes in these correlations at satellite altitudes.

Contribution

It provides a quantitative analysis of gravitational effects on quantum correlations in Earth's curved space-time, incorporating Earth's rotation and Kerr metric.

Findings

Correlations initially increase with satellite altitude then plateau.

Gravitational frequency shifts cause correlation changes up to 0.5% at geostationary orbit.

Quantum correlations are sensitive to Earth's gravitational effects.

Abstract

The preparation of quantum systems and the execution of quantum information tasks between distant users are always affected by gravitational and relativistic effects. In this work, we quantitatively analyze how the curved space-time background of the Earth affects the classical and quantum correlations between photon pairs that are initially prepared in a two-mode squeezed state. More specifically, considering the rotation of the Earth, the space-time around the Earth is described by the Kerr metric. Our results show that these state correlations, which initially increase for a specific range of satellite's orbital altitude, will gradually approach a finite value with increasing height of satellites orbit (when the special relativistic effects become relevant). More importantly, our analysis demonstrates that the changes of correlations generated by the total gravitational frequency shift could reach the level of <0.5$\%$ within the satellites height at geostationary Earth orbits.