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.

Long-Distance Distribution of Atom-Photon Entanglement at Telecom Wavelength.

Entanglement between stationary quantum memories and photonic channels is the essential resource for future quantum networks. Together with entanglement distillation, it will enable efficient distribution of quantum states. We report on the generation and observation of entanglement between a ^{87}Rb atom and a photon at telecom wavelength transmitted through up to 20 km of optical fiber.

Event-Ready Bell Test Using Entangled Atoms Simultaneously Closing Detection and Locality Loopholes.

An experimental test of Bell's inequality allows ruling out any local-realistic description of nature by measuring correlations between distant systems. While such tests are conceptually simple, there are strict requirements concerning the detection efficiency of the involved measurements, as well as the enforcement of spacelike separation between the measurement events. Only very recently could both loopholes be closed simultaneously.