Quantum Internet: Resource Estimation for Entanglement Routing

TL;DR

This paper analyzes how realistic experimental errors impact the resource requirements for scalable quantum networks, emphasizing the importance of high-fidelity gates and comparing different quantum platforms.

Contribution

It provides an analytical model for resource scaling in quantum networks considering errors, revealing stricter thresholds for efficiency and guiding platform selection.

Findings

Two-qubit gate error must be below 1.3% for efficient scaling

Trapped ions and diamond color centers are promising platforms

Previous implementations underestimated resource requirements

Abstract

Quantum repeaters have promised efficient scaling of quantum networks for over two decades. Despite numerous platforms proclaiming functional repeaters, the realization of large-scale networks remains elusive, indicating that the resources required to do so were thus far underestimated. Here, we investigate the dependence of resource scaling of networks on realistic experimental errors. Using a nested repeater protocol based on the purification protocol by Bennett et. al., we provide an analytical approximation of the polynomial degree of the resources consumed by entanglement routing. Our error model predicts substantially stricter thresholds for efficient network operation than previously suggested, requiring two-qubit gate errors below 1.3% for resource scaling with polynomial degree below 10. The analytical model presented here provides insight into the reason why previous experimental implementations of quantum repeaters failed to scale efficiently and inform the development of truly scalable systems, highlighting the need for high-fidelity local two-qubit gates. We employ our analytical approximation of the scaling exponent as a figure of merit to compare different platforms and find that trapped ions and color centers in diamond currently provide the best route towards large-scale networks.