Information-Spectrum General Formulas for the Capacity Region of Classical-Quantum Multiple Access Channels
Abstract
For classical-quantum multiple access channels (cq-MACs) with two senders, we give several general expressions for the capacity region, valid for arbitrary sequences of channels. In the case of asymptotically vanishing error (ε=0), the capacity region is expressed in terms of spectral inf-mutual information rates. For every 0≤ε<1, the ε-capacity region is expressed in terms of a quantity defined through a linear combination of three alternative hypotheses. In particular, the outer bound of Kubo and Nagaoka (2015) is tight. Our results include the quantum counterpart of the general formula of Han (1998) for the classical MAC. The most important ingredient is the one-shot inner bound of Sen (2021), which we apply to each member of an arbitrary channel sequence.
Related
- Information Spectrum Methods for ε-Capacity Problems in the Theory of Mixed Multiple-Access Channels with Cost Constraint
- Unlocking Exponential and Unbounded Robust Gains in Shannon Capacity of Classical Multiple Access Channels with Causal CSIT via Quantum Entanglement Assistance
- Weighted sum formulas for finite multiple mixed values
- Refined sum formulas for finite multiple zeta values of level two
- Duality formulas for 𝒬̂-multiple zeta values
BibTeX
@misc{kubo2026informationspectrum,
title = {{Information-Spectrum General Formulas for the Capacity Region of Classical-Quantum Multiple Access Channels}},
author = {Takuya Kubo and Hiroshi Nagaoka},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.07462},
eprint = {2611.07462},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.07462},
}
RIS
TY - UNPB
TI - Information-Spectrum General Formulas for the Capacity Region of Classical-Quantum Multiple Access Channels
AU - Takuya Kubo
AU - Hiroshi Nagaoka
PY - 2026
DA - 2026/11/05
PB - arXiv
DO - 10.48550/arxiv.2611.07462
UR - https://arxiv.org/abs/2611.07462
AB - For classical-quantum multiple access channels (cq-MACs) with two senders, we give several general expressions for the capacity region, valid for arbitrary sequences of channels. In the case of asymptotically vanishing error (ε=0), the capacity region is expressed in terms of spectral inf-mutual information rates. For every 0≤ε<1, the ε-capacity region is expressed in terms of a quantity defined through a linear combination of three alternative hypotheses. In particular, the outer bound of Kubo and Nagaoka (2015) is tight. Our results include the quantum counterpart of the general formula of Han (1998) for the classical MAC. The most important ingredient is the one-shot inner bound of Sen (2021), which we apply to each member of an arbitrary channel sequence.
ER -