By: New Scientist
August 15, 2020
Two observatories in China have used a quantum communications satellite to send an encrypted message a record-breaking 1200 kilometres – a major step towards building a secure quantum internet.
China launched its Micius quantum satellite in 2016. It produces pairs of photons that are quantum entangled, meaning the measured state of one photon is linked to the measured state of the other, regardless of the distance between them.
Entanglement can’t directly transfer information, because that would mean data is travelling faster than light. But entangled particles can be used to create secret “keys” that enable extraordinarily secure communication.
Artur Ekert at the University of Oxford and his colleagues used Micius to beam entangled photons to observatories 1200 kilometres apart in China, allowing those two observatories to share quantum encrypted data from farther apart than ever before.