Quantum network communication: a discrete-time quantum-walk approach

We study the problem of quantum multi-unicast communication over the butterfly network in a quantum-walk architecture, where multiple arbitrary single-qubit states are transmitted simultaneously between multiple source-sink pairs. Here, by introducing quantum walks, we demonstrate a quantum multiunicast communication scheme over the butterfly network and the inverted crown network, respectively,where the arbitrary single-qubit states can be efficiently transferred with both the probability and the state fidelity one. The presented result concerns only the butterfly network and the inverted crown network, but our techniques can be applied to a more general graph. It paves a way to combine quantum computation and quantum network communication.