Thursday, May 24, 2012

Entanglement and the emergence of time

There's an international competition underway to create the first secure quantum cryptographic channel to an orbital satellite. Today's record is 150 kilometers.

I can't judge the security significance of this competition; it probably depends on how good quantum computers will be at factoring. Perhaps a quantum communications channel will be the only practical defense against quantum computing decryption, though my trusted expert is somewhat skeptical.

I can say, however, that humans are remarkably blase about how insanely weird it is to have technologies based on magic.

Magic, or something indistinguishable from it. This stuff is all powered by "entanglement", the modest little word that means measurement of entangled states at opposite "ends" of the universe will be "instantaneously" "correlated". [1][2]

It's been said physicists deal with this by not talking about it. I am certain, however, that many physicists think about it quite a bit. I imagine I see these thoughts around the edges of blog posts on nature of time.

Since I'm very much not a smart enough to be a physicist, I can speculate freely about what I think they're thinking. I think they think that entanglement is telling us that time is not fundamental; that in a sense everything and nothing happens all at once. When correlation can happen outside of a light cone, then time isn't what we thought it was.

I'm on the lookout now for physicists starting to mutter these thoughts aloud.

[1] Words really fail at this. I'm trying to avoid words like "cause". Also "instantaneous" is almost certainly wrong or right.
[2] We're told that there's no way to communicate information through this correlation; though something I read recently made me wonder if physicists were finding a way to cheat this rule (I can't find the link).

See also:

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