Year: 2026
Type: preprint
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.
Source: arXiv (Cornell University)
Authors: Mizrahi, Elsa, Pereg, Uzi
Institutions: Télécom Paris, Institut Polytechnique de Paris
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: Israel Science Foundation
Awards: G2792009719, G7919740695
OpenAlex ID: W7223067502