Free-Space distribution of entanglement and single photons over 144 km

摘要: Quantum Entanglement is the essence of quantum physics and inspires fundamental questions about principles nature. Moreover it also basis for emerging technologies information processing such as cryptography, teleportation computation. Bell's discovery, that correlations measured on entangled systems are at variance with a local realistic picture led to flurry experiments confirming predictions. However, still experimentally undecided whether entanglement can survive global distances, predicted by theory. Here we report violation Clauser-Horne-Shimony-Holt (CHSH) inequality two observers separated 144 km between Canary Islands La Palma Tenerife via an optical free-space link using Optical Ground Station (OGS) European Space Agency (ESA). Furthermore used pairs generate cryptographic key under experimental conditions constraints characteristic Space-to-ground experiment. The distance in our experiment exceeds all previous more than one order magnitude exploits limit ground-based communication; significantly longer distances only be reached air- or space-based platforms. range achieved thereby demonstrates feasibility communication space, involving satellites International (ISS).