Quantum Communication in Rindler Spacetime

TL;DR

This paper investigates how Unruh radiation affects quantum and private communication capacities between inertial and accelerating observers, providing formulas and theoretical insights into these relativistic quantum channels.

Contribution

It introduces a rigorous framework for private quantum capacity in relativistic settings and analyzes the structure of Unruh channels, including their group-theoretic properties and conjugate degradability.

Findings

Derived compact formulas for communication capacities under Unruh noise

Proved that Unruh channels are conjugate degradable

Connected Unruh channels to optical amplifier models

Abstract

A state that an inertial observer in Minkowski space perceives to be the vacuum will appear to an accelerating observer to be a thermal bath of radiation. We study the impact of this Davies-Fulling-Unruh noise on communication, particularly quantum communication from an inertial sender to an accelerating observer and private communication between two inertial observers in the presence of an accelerating eavesdropper. In both cases, we establish compact, tractable formulas for the associated communication capacities assuming encodings that allow a single excitation in one of a fixed number of modes per use of the communications channel. Our contributions include a rigorous presentation of the general theory of the private quantum capacity as well as a detailed analysis of the structure of these channels, including their group-theoretic properties and a proof that they are conjugate degradable. Connections between the Unruh channel and optical amplifiers are also discussed.