Design Tradeoffs in Photonically Linked Qubit Networks

Abstract

Quantum networking can be realized by distributing pairs of entangled qubits between remote quantum processing nodes. Devoted communication qubits within each node can naturally interface with photons which bus quantum information between nodes. With the introduction of CQED to enhance interactions between communication qubits and photons, advanced protocols capable of achieving high entanglement distribution rates with high fidelity become feasible. In this paper, we consider two such protocols based on trapped ion communication qubits strongly coupled to small optical cavities. We study the rate and fidelity performance of these protocols as a function of critical device parameters and the photonic degree of freedom used to carry the quantum information. We compare the performance of these protocols with the traditional two-photon interference scheme, subjecting all protocols to the same experimentally relevant constraints. We find that adoption of the strong-coupling protocols could provide substantial distribution rate improvements of $30-75\%$ while maintaining the high-fidelities $\mathcal{F}\gtrsim99\%$ of the traditional scheme.