Data Transmission over a Bosonic Arbitrarily Varying Quantum Channel

TL;DR

This paper establishes a capacity formula for a class of quantum channels affected by semi-classical attacks, enhancing understanding of quantum communication robustness under adversarial conditions.

Contribution

It provides an explicit capacity formula for lossy bosonic channels under semi-classical attacks, connecting it with a new quantum entropy power inequality.

Findings

Derived a capacity formula for the channel model

Linked the capacity to a conjectured quantum entropy power inequality

Demonstrated robustness analysis for quantum communication systems

Abstract

Arbitrarily varying channels offer a powerful framework for analyzing the robustness of quantum communication systems, especially for classical-quantum models, where the analysis displays strengths or weaknesses of specific signal constellations under generic attacks. In this work, we provide a coding theorem for a large class of practically relevant arbitrarily varying channel models. Namely, we give an explicit capacity formula for the lossy bosonic channel subject to semi-classical attacks, where an adversary injects semi-classical states into the transmission line. Mathematically, this is modeled via a beam-splitter setup, with transmitter and jammer controlling different input ports and the receiver observing one output port. We show how a recently conjectured new quantum entropy power inequality relates to our capacity formula.