title: An elementary quantum network of single atoms in optical cavities.
abstract: 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.
authors.affiliation: Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany. stephan.ritter@mpq.mpg.de
authors.forename: Stephan
authors.initials: S
authors.lastname: Ritter
authors.forename: Christian
authors.initials: C
authors.lastname: Nölleke
authors.forename: Carolin
authors.initials: C
authors.lastname: Hahn
authors.forename: Andreas
authors.initials: A
authors.lastname: Reiserer
authors.forename: Andreas
authors.initials: A
authors.lastname: Neuzner
authors.forename: Manuel
authors.initials: M
authors.lastname: Uphoff
authors.forename: Martin
authors.initials: M
authors.lastname: Mücke
authors.forename: Eden
authors.initials: E
authors.lastname: Figueroa
authors.forename: Joerg
authors.initials: J
authors.lastname: Bochmann
authors.forename: Gerhard
authors.initials: G
authors.lastname: Rempe