Kicking off a two-year mission, the Micius satellite will test out quantum communications over greater distances than ever tried on the ground. It will help establish an encrypted connection between ground stations in China and Austria with the help of scientists in both countries.
“We have been doing things like quantum cryptography and quantum teleportation, and other things, in the lab beginning in the mid-1990s, and we have extended this outside the lab, with experiments between two islands of the Canary Islands with distances of 100 miles or so,” said Anton Zeilinger, a professor of experimental physics at the University of Vienna. “Now, the next logical step is the satellite.”
The concept calls for an instrument aboard the newly-launched satellite to generate a pair of photons, tiny sub-atomic particles of light. Then a high-power telescope on satellite will beam one half of the pair to ground stations in China and Europe.
The photons will be in a quantum state, meaning their properties depend on the other. Quantum entanglement has never been proven over such great distances before.
Scientists on the ground will use the photons to create a secret key, allowing messages to be exchanged between Europe and China via conventional networks like the Internet. The key is needed to break the encrypted code.
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