Satellite-Based Entanglement Distribution Over 1200 kilometers

Understand

Long-distance entanglement distribution is essential both for foundational tests of quantum physics and scalable quantum networks.

• Owing to channel loss, however, the previously achieved distance was limited to ~100 km.
• Here, we demonstrate satellite-based distribution of entangled photon pairs to two locations separated by 1203 km on the Earth, through satellite-to-ground two-downlink with a sum of length varies from 1600 km to 2400 km.
• We observe a survival of two-photon entanglement and a violation of Bell inequality by 2.37+/-0.09 under strict Einstein locality conditions.