

Send messages to the future with Quantum Entanglement - wicknicks
http://www.wired.com/wiredscience/2011/01/timelike-entanglement/

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jarin
Not to diminish the scientific value of this discovery, but there's also
another way to send messages to the future:
<http://en.wikipedia.org/wiki/Writing>

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sorbus
The advantage of this would be sending a message which cannot be known until a
point in the future - sort of like a time capsule with a lock that only opens
on a certain day, but way more secure. While, for most purposes, merely
storing encrypted information and only revealing the key later might be
better, there are probably some things very paranoid people could use this for
(a message that arrives after 100 years, for instance, could reveal all sorts
of things, as the author would know that he would be dead by then). However,
it's not very useful for practical purposes.

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MartinCron
I'm reminded about how Mark Twain put an embargo on parts of his
autobiography, not to be released for 100 years after his death.

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codex
Forgive my ignorance of quantum physics, but would it be possible to use
entanglement to send messages back in time? If not, why would entanglement
work in only one direction (forwards)?

There is a causality argument, but I don't why it would be impossible that
reading a message from the future cannot alter that future. Just because a
future universe occurred once doesn't mean that it has to occur again once
particles have been entangled, does it? Aside from being very strange, would
such a scenario violate any known laws of physics?

There is this: <http://en.wikipedia.org/wiki/No-communication_theorem>, which,
unfortunately, is beyond me.

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lisper
There are prosaic (by which I mean classical, non-quantum) means of
accomplishing the same thing, e.g. encrypt a classical message using a one-
time pad and send the resulting ciphertext and keystreams in opposite
directions at the speed of light. The original data can be recovered if and
only iff both data streams are reflected back to some common point in space
and recombined. If the initial transmission is at time T0, and the first
reflection happens at time T1, then the recombination cannot happen until
T1+(T1-T0). I'm not sure if this is 100% analogous to what is being done in
this paper (the math is kinda furry) but I'm pretty sure it's close.

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MichaelApproved
I don't believe the Star Trek analogy was correct. In the episode, Scotty had
his pattern repeat in some sort of cycle that kept his pattern safe. He didn't
send himself to a specific point in time, he could have pulled out of it at
any point. In fact, his crewmate died because he wasn't pulled out soon enough
and his pattern degraded.

Scotty in the transporter was more like stasis and not a teleport to the
future.

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geuis
Ugh, typical poor science journalism strikes again. Quantum entanglement can
absolutely _not_ be used to transfer information. Two problems are you can't
travel faster than light, information included, and second is measuring the
spin of an entangled particle only works if you know the state of the other
one.

So no, you cannot transmit encyclopedias of data using quantum entanglement.

As for the rest of the story, it sounds like entanglement can work across
time. Flipping the state in the past instantly flips it in the future.
However, in either direction of time the observer already knows the state so
no info transfer, no causality breakage.

