Quantum interference may become a useful secure comms tool, reckon scientists

It may be possible to send quantum-encrypted messages through space, after physicists showed a beam of light sent to a satellite could return to Earth with its quantum properties intact, according to new research published in Physical Review Letters.

First, the scientists split a photon into two and shone the two halves through an optical apparatus that would allow them to recombine later on.

Professor Alexander Sergienko told Science News: "Whether this could survive such long distances and harsh experimental conditions, that was a big question," who works in the Quantum Communication & Measurement Laboratory at Boston University.

The photons also returned to earth with their polarisation states intact which showed that quantum information could be stored in its polarisation state.

Sending encrypted messages through altering photons' temporal superposition is more secure than using polarisation states, as research to date has concentrated on.

The polarisation state might change when the photon bounces off the satellite's reflectors, which causes the photon to lose information on its previous polarisation state.

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