An elementary quantum network of single atoms in optical cavities

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.


Fraunhofer-Verbund Mikroelektronik: Data from an LED ceiling light

Commercially available light-emitting diodes (LEDs) can do more than just generate light. Researchers at the Fraunhofer Heinrich Hertz Institute HHI have succeeded in transmitting broadband data streams within visible light via LED lamps to computers or other end devices that can receive data. ???Visible light communication??? is the name of this new transmission technology