Entanglement-assisted private communication over a classical-quantum multiple-access channel
Phys. Rev. A 112, 012618 – Published 22 July, 2025
DOI: https://doi.org/10.1103/2gbl-yb3v
Abstract
We consider entanglement-assisted private communication over a classical-quantum multiple-access channel with two senders and a single receiver. We initially determine the capacity region where senders and receiver share unlimited entanglement resources. In this setting, each sender performs an encoding measurement on their share of the entangled state to transmit a measurement outcome via the classical-quantum multiple-access channel. Meanwhile, the receiver applies a decoding operation to both the channel's output state and their share of the entangled state. We further derive the private capacity. Moreover, we consider the capacity region and private capacity when entanglement is shared between only the two senders. This corresponds to a quantum extension of the classical multiple-access channel with entanglement. Significantly, we show that the capacity region when both senders share entanglement with the receiver is strictly larger than when only the two senders share the entanglement.
