Entanglement of nanophotonic quantum memory nodes in a telecom network
A recent study published in Nature explores the entanglement of nanophotonic quantum memory nodes in a telecom network, marking a significant advancement in the field of quantum communication. The research, conducted by a team of scientists led by C. M. Knaut and M. D. Lukin, showcases the successful entanglement of two quantum memory nodes over long distances using innovative technology.
The key challenge in establishing practical quantum networks for long-distance quantum communication lies in ensuring robust entanglement between quantum memory nodes connected by fiber optic infrastructure. In this study, the researchers demonstrate a two-node quantum network comprising multi-qubit registers based on silicon-vacancy (SiV) centers in nanophotonic diamond cavities integrated with a telecommunication fiber network.
Remote entanglement is achieved through cavity-enhanced interactions between the electron spin qubits of the SiVs and optical photons. The team employs serial, heralded spin-photon entangling gate operations with time-bin qubits to establish robust entanglement between separated nodes. Long-lived nuclear spin qubits are utilized to provide second-long entanglement storage and integrated error detection mechanisms.
One of the key innovations in the study is the integration of efficient bidirectional quantum frequency conversion of photonic communication qubits to telecommunication frequencies (1,350 nm). This integration enables the entanglement of two nuclear spin memories through 40 km spools of low-loss fiber and a 35 km long fiber loop deployed in an urban environment in Boston.
This achievement represents a significant step towards the practical implementation of quantum repeaters and large-scale quantum networks. Establishing entanglement between quantum memory nodes separated by extended distances is crucial for the development of quantum networks with diverse applications, including quantum repeaters, long-distance secure communication, distributed quantum computing, and quantum sensing.
The successful demonstration of entanglement in a telecom network paves the way for further advancements in quantum communication technology, bringing us closer to realizing the full potential of quantum networks for various applications in the future.
