Superadditivity of Zero-Error Capacity in Noisy Classical and Perfect Quantum Channel Pairs
Abstract
We demonstrate superadditivity of one-shot zero-error classical capacity in an asymmetric communication setting where a noisy classical channel is used in parallel with a perfect quantum channel. Each channel individually supports only a fixed number of perfectly distinguishable messages. Their joint use enables transmission of strictly more messages than permitted by the product of the individual capacities. We present explicit constructions achieving this enhancement and establish that replacing the perfect quantum channel with a perfect classical channel eliminates the effect. Finally, we identify a structural criterion on the noisy channel governing this effect and show that the quantum advantage is rooted in Kochen-Specker contextuality.
Keywords
Cite
@article{arxiv.2601.08913,
title = {Superadditivity of Zero-Error Capacity in Noisy Classical and Perfect Quantum Channel Pairs},
author = {Ambuj and Anushko Chattopadhyay and Kunika Agarwal and Rakesh Das and Amit Mukherjee},
journal= {arXiv preprint arXiv:2601.08913},
year = {2026}
}
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