

Signals from space to Earth could confirm Einstein's worst fear - theoneill
http://www.sciencenews.org/view/feature/id/34237/title/Decoding_the_Quantum_Mystery

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SirWart
Ugh, this article is full of misconceptions about quantum mechanics.

Particle wave duality: Particles are not either particles or waves depending
on how you measure them. A more accurate description might be quantized waves,
but really calling an electron a particle or a wave is applying a faulty
analogy to them.

This experiment will prove something new about entanglement: Scientists have
already sent entangled photons and demonstrated quantum cryptography over long
distances through the air. 144 km is the current
record.(<http://lanl.arxiv.org/abs/quant-ph/0607182>)

Quantum cryptography will make things more secure: Public key encryption is
actually really good and you can make things arbitrary secure by changing the
key length used (You can make accurate predictions about how long and how much
money it will cost to break a given key length). People talk about quantum
computing blowing open public key encryption, but in reality that just isn't
going to happen. (see
[http://www.emergentchaos.com/archives/2008/03/quantum_progre...](http://www.emergentchaos.com/archives/2008/03/quantum_progress.html)
for a good discussion of that). Quantum cryptography also has a ton of other
practical limitations which means it will probably only be used by people who
don't understand public key encryption (right now there is no known way to
route photons or repeat them so not only are you limited on distance but you
have to trust every node that the message passes through for the actual
communication to be secure).

~~~
hugh
I agree, this article is terrible.

I do think quantum cryptography has a place, though, especially if they manage
to demonstrate it in satellite-to-earth communications (which is what I assume
this article is about, although I couldn't bring myself to do more than skim
it). It's good for those folks who are (a) paranoid enough not to want their
messages read even a hundred years after they are sent, and (b) are rich
enough to buy a satellite. Which pretty much limits it to governments, I
guess.

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nazgulnarsil
I think the wave particle analogy problem is simply that we've reached a scale
where the physical properties of the universe don't necessarily have human
scale analogues. It is impossible for us to visualize things that can't exist
at our scale. I think a sentient intelligence that lived at the scale of
photons would be equally confused by our concept of waves.

