Quantum Entanglement Assistance Improves the Capacity and Activates the Zero-Error Capacity of Classical Channels with Causal CSIT

TL;DR

This paper demonstrates that quantum entanglement assistance can enhance the capacity and activate the zero-error capacity of classical channels with causal CSIT, contrasting prior results for channels without such information.

Contribution

It reveals that quantum entanglement can improve classical channel capacities specifically when causal CSIT is available, a novel insight in quantum information theory.

Findings

Quantum entanglement can increase channel capacity with causal CSIT.

Entanglement can activate zero-error capacity in certain classical channels.

Contrasts with previous results where entanglement had no effect without CSIT.

Abstract

For classical point-to-point channels, it has been shown by Bennett et al. that quantum entanglement assistance cannot improve their capacity, and by Cubitt et al. that entanglement assistance cannot activate (increase from zero to non-zero) their zero-error capacity. In contrast, we show that for classical point-to-point channels with causal CSIT (channel state information at the transmitter), quantum entanglement assistance can in some cases improve their capacity, and in some cases activate their zero-error capacity.