On the classical capacity of a quantum multiple-access channel

Abstract

We analyze the quantum adder channel, i.e. the extension of a classical multiple-access additive binary channel to the quantum regime, in which quantum bits (qubits) rather than classical bits are transmitted. Quantum entanglement between different transmitters and/or the receiver results in a significant expansion of the capacity region of the channel, in comparison with its classical counterpart, a property which can be used, e.g., to considerably improve bandwidth efficiency of fiber communication networks in the future.