Transmission of quantum information through quantum fields in curved spacetimes

TL;DR

This paper develops a covariant quantum communication channel model in curved spacetimes, demonstrating maximum quantum capacity achievable via relativistic quantum fields and algebraic quantum field theory techniques.

Contribution

It introduces a covariant framework for quantum communication in curved spacetimes, expressing quantum capacity through field correlation functions and causal propagators.

Findings

Achieves maximum quantum capacity in arbitrary curved spacetimes.

Channel construction respects causal structure and background independence.

Uses algebraic quantum field theory for a covariant description.

Abstract

We construct a relativistic quantum communication channel between two localized qubit systems, mediated by a relativistic quantum field, that can achieve the theoretical maximum for the quantum capacity in arbitrary curved spacetimes using the Unruh-DeWitt detector formalism. Using techniques from algebraic quantum field theory, we express the quantum capacity of the quantum communication channel purely in terms of the correlation functions of the field and the causal propagator for the wave equation. Consequently, the resulting quantum channel, and hence the quantum capacity, are by construction manifestly covariant, respect the causal structure of spacetime, and are independent of the details of the background geometry, topology, and the choice of Hilbert space (quasifree) representations of the field.