Quantum network coding for quantum repeaters

TL;DR

This paper introduces a practical quantum network coding protocol suitable for quantum repeater networks, demonstrating increased transmission rates under realistic constraints where quantum resources are limited.

Contribution

The work presents the first quantum network coding protocol effective in quantum repeater networks with minimal initial quantum resources, expanding practical applicability.

Findings

Quantum network coding can enhance transmission rates in repeater networks.

The protocol operates with only shared EPR pairs and no additional quantum registers.

This approach is feasible under realistic network constraints.

Abstract

This paper considers quantum network coding, which is a recent technique that enables quantum information to be sent on complex networks at higher rates than by using straightforward routing strategies. Kobayashi et al. have recently showed the potential of this technique by demonstrating how any classical network coding protocol gives rise to a quantum network coding protocol. They nevertheless primarily focused on an abstract model, in which quantum resource such as quantum registers can be freely introduced at each node. In this work, we present a protocol for quantum network coding under weaker (and more practical) assumptions: our new protocol works even for quantum networks where adjacent nodes initially share one EPR-pair but cannot add any quantum registers or send any quantum information. A typically example of networks satisfying this assumption is {\emph{quantum repeater networks}}, which are promising candidates for the implementation of large scale quantum networks. Our results thus show, for the first time, that quantum network coding techniques can increase the transmission rate in such quantum networks as well.