Information gap for classical and quantum communication in a Schwarzschild spacetime

TL;DR

This paper investigates how Unruh-Hawking noise affects classical and quantum communication near a black hole horizon, showing classical correlations persist while quantum coherence vanishes at high acceleration.

Contribution

It demonstrates the impact of black hole-induced noise on communication channels, revealing the persistence of classical correlations despite the loss of quantum coherence.

Findings

Classical channel capacity reaches a finite limit under extreme acceleration.

Quantum coherent information tends to zero at high acceleration.

Classical correlations remain even when quantum coherence is destroyed.

Abstract

Communication between a free-falling observer and an observer hovering above the Schwarzschild horizon of a black hole suffers from Unruh-Hawking noise, which degrades communication channels. Ignoring time dilation, which affects all channels equally, we show that for bosonic communication using single and dual rail encoding the classical channel capacity reaches a finite value and the quantum coherent information tends to zero. We conclude that classical correlations still exist at infinite acceleration, whereas the quantum coherence is fully removed.