Satellite-based quantum steering under the influence of spacetime curvature of the Earth

TL;DR

This paper investigates how Earth's spacetime curvature affects quantum steering of photon pairs in satellite-based quantum communication, revealing that gravitational effects can enhance or asymmetrize quantum correlations.

Contribution

It demonstrates the impact of Earth's curved spacetime on Gaussian quantum steering, including effects of satellite height and spacetime rotation, which was previously unexplored.

Findings

Quantum steerability varies with satellite height.

Spacetime curvature induces asymmetry in quantum steering.

Rotation of spacetime (Kerr) alters gravitational effects on steering.

Abstract

Spacetime curvature of the Earth deforms wavepackets of photons sent from the Earth to satellites, thus influencing the quantum state of light. We show that Gaussian steering of photon pairs, which are initially prepared in a two-mode squeezed state, is affected by the curved spacetime background of the Earth. We demonstrate that quantum steerability of the state increases for a specific range of height $h$ and then gradually approaches a finite value with further increasing height of the satellite's orbit. Comparing with the peak frequency parameter, the Gaussian steering changes more for different squeezing parameters, while the gravitational frequency effect leads to quantum steering asymmetry between the photon pairs. In addition, we find that the influence of spacetime curvature on the steering in the Kerr spacetime is very different from the non-rotating case because special relativistic effects are involved.