QUROPE Quantum Information Processing and Communication in Europe

Devices that harness the laws of quantum physics hold the promise for information processing that outperforms their classical counterparts, and for unconditionally secure communication. However, in particular, implementations based on condensed-matter systems face the challenge of short coherence times. Carbon materials, particularly diamond, however, are suitable for hosting robust solid-state quantum registers, owing to their spin-free lattice and weak spin–orbit coupling.

Projective measurement of single electron and nuclear spins has evolved from a gedanken experiment to a problem relevant for applications in atomic-scale technologies like quantum computing. Although several approaches allow for detection of a spin of single atoms and molecules, multiple repetitions of the experiment that are usually required for achieving a detectable signal obscure the intrinsic quantum nature of the spin’s behavior.

The generation of entangled photon pairs is usually a complex process involving optically driven schemes and nonlinear optics. The recent demonstration of an electrically powered light-emitting diode that is capable of this task looks set to greatly simplify experiments in the field of quantum information processing.