A device-independent quantum key distribution system for distant users.

Device-independent quantum key distribution (DIQKD) enables the generation of secret keys over an untrusted channel using uncharacterized and potentially untrusted devices. The proper and secure functioning of the devices can be certified by a statistical test using a Bell inequality. This test originates from the foundations of quantum physics and also ensures robustness against implementation loopholes, thereby leaving only the integrity of the users' locations to be guaranteed by other means.

Entangling single atoms over 33 km telecom fibre.

Quantum networks promise to provide the infrastructure for many disruptive applications, such as efficient long-distance quantum communication and distributed quantum computing. Central to these networks is the ability to distribute entanglement between distant nodes using photonic channels. Initially developed for quantum teleportation and loophole-free tests of Bell's inequality, recently, entanglement distribution has also been achieved over telecom fibres and analysed retrospectively.