Classical and quantum capacities of a fully correlated amplitude damping channel

TL;DR

This paper analyzes the capacities of a fully correlated amplitude damping channel for two qubits, highlighting the necessity of entanglement for optimal performance and computing various capacity measures.

Contribution

It derives the single-shot classical capacity, examines the channel's degradability, and calculates quantum and entanglement-assisted capacities for all noise levels.

Findings

Entanglement enhances channel capacity.

Quantum capacity varies with noise parameter.

Entanglement-assisted capacity is explicitly computed.

Abstract

We study information transmission over a fully correlated amplitude damping channel acting on two qubits. We derive the single-shot classical channel capacity and show that entanglement is needed to achieve the channel best performance. We discuss the degradability properties of the channel and evaluate the quantum capacity for any value of the noise parameter. We finally compute the entanglement-assisted classical channel capacity.