Quantum Entanglement, Dark Counts, Coincidence Detection

[caraher]

28. What's available now is quantum-secured distribution of encryption keys

The thing to remember is that the encryption keys are themselves randomly generated, and thus exchange no information between Alice and Bob (the two people seeking to exchange encrypted information). What BB84 and other protocols do is give you a sort of "tamper evident" way of exchanging encryption keys, which are then used to encode and decode information sent over classical channels. Turning a stream of measurements on entangled photons into an encryption key always involves Alice and Bob comparing notes on the measurements they made and the results of the measurements over a classical channel. This means that you don't get superluminal communication, even though the measurements they make, individually, do involve evidently nonlocal interactions.

So I don't think you can use this to achieve negative latency, for instance, because the information doesn't lie in the entangled photons. Unless, of course, something radically different is going on. It's been a while since I've given much attention to Cramer's transactional interpretation, but it's very important to remember that to the extent it might allow for such communication it goes beyond (and contradicts) standard quantum mechanics. That doesn't mean it's wrong, of course; that's what experiments are for! (Or proofs...)