Establishing High-Fidelity Entanglement in Quantum Repeater Chains

Entanglement is crucial for many applications such as quantum computing, quantum sensing, and quantum communication. Establishment of entanglement between remote nodes, referred to as remote entanglement establishment (REE), is a key element of the quantum internet. This paper develops a theoretical framework for establishing high-fidelity entanglement between two remote nodes of a quantum repeater chain via entanglement generation, distillation, and swapping operations. In particular, an upper bound on the optimal REE rate under minimum fidelity requirements is established, and an REE policy that achieves such a bound asymptotically is presented. Results in this paper provide guidelines for protocol design in the quantum internet.