Quantum network coding utilizing quantum discord resource fully

Secure and faithful transmission of quantum information between remote locations is still a basic topic in quantum communication. Beyond remote state preparation and entanglement distribution by separable states, quantum discord, as a more general quantum communication resource, controls the realization of the whole communication process. In this paper, we propose a feasible quantum network coding scheme utilizing quantum discord resource fully. With the help of entanglement distribution by separable states, the scheme initially achieves quantum entanglement distribution of two crossing source-target pairs in a butterfly network with fewer entanglement resources. Furthermore, by means of remote state preparation, known quantum states can be transmitted across a network via previously shared quantum channels with the assistance of some classical information. Compared with the representative schemes, the proposed scheme is more efficient in the use of quantum resources. The deduced relationship indicates that quantum discord is the necessary resource for quantum network coding based on remote state preparation, particularly, less entanglement corresponds to higher fidelity.