Can Quantum Entanglement Increase the Capacity of a Classical Relay Channel?
Abstract
We show positive and negative results on classical relay channels with entanglement assistance, revealing a sharp contrast between strictly causal and causal relay encoding. First, we consider van der Meulen's setting of a unit-delay relay, with strictly causal encoding. We show that the standard cutset upper bound continues to hold with entanglement assistance, and deduce that entanglement does not increase the capacity for several classes of relay channels. Second, we consider a zero-delay relay, where the encoding is causal. We present an example in which entanglement enables rates that exceed the cutset upper bound by at least 12.5%. Namely, entanglement shared between the source and relay significantly increases the capacity of a classical zero-delay relay channel.
Related
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BibTeX
@misc{mizrahi2026quantum,
title = {{Can Quantum Entanglement Increase the Capacity of a Classical Relay Channel?}},
author = {Elsa Mizrahi and Uzi Pereg},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.25334},
eprint = {2610.25334},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.25334},
}
RIS
TY - UNPB
TI - Can Quantum Entanglement Increase the Capacity of a Classical Relay Channel?
AU - Elsa Mizrahi
AU - Uzi Pereg
PY - 2026
DA - 2026/10/18
PB - arXiv
DO - 10.48550/arxiv.2610.25334
UR - https://arxiv.org/abs/2610.25334
AB - We show positive and negative results on classical relay channels with entanglement assistance, revealing a sharp contrast between strictly causal and causal relay encoding. First, we consider van der Meulen's setting of a unit-delay relay, with strictly causal encoding. We show that the standard cutset upper bound continues to hold with entanglement assistance, and deduce that entanglement does not increase the capacity for several classes of relay channels. Second, we consider a zero-delay relay, where the encoding is causal. We present an example in which entanglement enables rates that exceed the cutset upper bound by at least 12.5%. Namely, entanglement shared between the source and relay significantly increases the capacity of a classical zero-delay relay channel.
ER -