Noncooperative Quantum Networks

TL;DR

This paper reveals that in noncooperative quantum networks, adding more entanglement can decrease fidelity, highlighting challenges in resource optimization due to a quantum analog of selfish routing.

Contribution

It introduces the concept that noncooperative LOCC protocols can lead to decreased fidelity with increased entanglement, a novel insight into quantum network resource management.

Findings

Fidelity may decrease as entanglement increases in noncooperative protocols.

Noncooperative LOCC protocols can exhibit a quantum analog of selfish routing.

Resource allocation in quantum networks faces potential obstacles due to non-monotonic fidelity behavior.

Abstract

Existing protocols for quantum communication networks usually assume an initial allocation of quantum entanglement resources, which are then manipulated through local operations and classical communication (LOCC) to establish high-fidelity entanglement between distant parties. It is generally held that the resulting fidelity would increase monotonically with the entanglement budget. Here, we show that for noncooperative LOCC protocols, the resulting fidelity may decrease as more entanglement is added to a network with non-pure states. This effect results from a quantum analog of selfish routing and constitutes a potential obstacle to the optimal use of resources in large quantum networks.