QUANTUM REPEATER AND SYSTEM AND METHOD FOR CREATING EXTENDED ENTANGLEMENTS

摘要

A method is provided of creating an end-to-end entanglement (87) between qubits in first and second end nodes (81, 82) of a chain of optically-coupled nodes whose intermediate nodes (80) are quantum repeaters. Local entanglements (85) are created on an on-going basis between qubits in neighbouring pairs in the chain through interaction of the qubits with light fields transmitted between the nodes. The quantum repeaters (80) are cyclically operated with their top-level operating cycles being synchronized. Once every top-level operating cycle, each repeater (80) initiates a merging of two entanglements involving respective repeater qubits that are at least expected to be entangled with qubits in nodes disposed in opposite directions along the chain from the repeater. A quantum repeater (80) adapted for implementing this method is also provided.