That’s a reasonable bit rate at distances that are certain to be useful for various interested parties. It’s not hard to imagine it being used to send a secure video feed from an autonomous sub for example.
Of course, these results are the theoretical maximum. In practice, however, the distances would be significantly shorter without technologies that can help screen out the noise. Peng and co suggest that placing 450 nm filters over the detectors or gating them so they only look for photons during the short time window over which they ought to arrive.
Either way, we ought to see experiments in this area starting relatively soon (if they haven’t already been done in secret). It’s worth pointing out that the early tests on quantum key distribution through the atmosphere started at very modest distances. But in 2007, researchers reported successful quantum communication over a distance of 144 km
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