Quantum Entanglement Assistance Improves the Capacity and Activates the Zero-Error Capacity of Classical Channels with Causal CSIT
This work addresses a fundamental problem in quantum information theory by revealing new capabilities in channel coding, though it is incremental as it builds on existing frameworks with a specific condition (causal CSIT).
The paper demonstrates that quantum entanglement assistance can enhance the capacity and activate the zero-error capacity of classical channels with causal CSIT, contrasting with prior results showing no such improvements for channels without CSIT.
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.