Entanglement of Remote Ion Memories with Cavity Enhanced Matter-Light Interactions

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 thesis, I weigh the advantages of three protocols based on photon-mediated interactions between trapped ions coupled to small optical cavities. This includes a cavity-enhanced variant of the traditional two-photon entanglement swapping scheme as well as two alternative pitch-and-catch schemes which rely on coherent photon scattering events. I describe current experimental progress towards integrating sub-millimeter optical cavities with contemporary ion trap platforms, identifying the physical constraints which limit all three protocols. I 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. Surprisingly, a consistent application of the assumptions used to support the adoption of the traditional protocol makes a stronger case for the alternative schemes. We find that adoption of the strong-coupling protocols could provide substantial distribution rate improvements of 30-75% while maintaining the high-fidelities of the traditional scheme.