An elementary quantum network of single atoms in optical cavities

• Published in: Nature 2012, Vol.484 (7393), p.195
• Main Authors: Ritter, Stephan, Nolleke, Christian, Hahn, Carolin, Reiserer, Andreas, Neuzner, Andreas, Uphoff, Manuel, Mucke, Ma, Figueroa, Eden, Bochmann, Joerg, Rempe, Gerhard
• Format: Report
• Language: English
• Subjects: Atoms; Properties; Quantum computing; Quantum optics
• ISSN: 0028-0836
• DOI: 10.1038/nature11023

Quantum networks are distributed quantum many-body systems with tailored topology and controlled information exchange. They are the backbone of distributed quantum computing architectures and quantum communication. Here we present a prototype of such a quantum network based on single atoms embedded in optical cavities. We show that atom-cavity systems form universal nodes capable of sending, receiving, storing and releasing photonic quantum information. Quantum connectivity between nodes is achieved in the conceptually most fundamental way--by the coherent exchange of a single photon. We demonstrate the faithful transfer of an atomic quantum state and the creation of entanglement between two identical nodes in separate laboratories. The non-local state that is created is manipulated by local quantum bit (qubit) rotation. This efficient cavity-based approach to quantum networking is particularly promising because it offers a clear perspective for scalability, thus paving the way towards large-scale quantum networks and their applications.