
Scientists Report Finding Reliable Way to Teleport Data - SnarfDragon
http://www.nytimes.com/2014/05/30/science/scientists-report-finding-reliable-way-to-teleport-data.html?hp&_r=1
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jpmattia
Mods should switch to the NYT headline ("Scientists Report Finding Reliable
Way to Teleport Data"), which is appropriate. The current HN headline ("New
Research in Faster-than-light Communication") is out to lunch.

Entanglement is not FTL communication.

Edit (having now skimmed the paper from Spittie
[http://arxiv.org/abs/1404.4369](http://arxiv.org/abs/1404.4369)): Quantum
teleportation isn't FTL communication either.

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duaneb
It doesn't even teleport the data. It merely shares the same state—you can't
move information through this shared state.

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ghshephard
Notice the headline doesn't say teleport _information_ , but instead says
teleport _data_ \- which is accurate. I agree, the Title on HN is a degraded
version of the NYT version.

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duaneb
What is data without semantics? A RNG?

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jloughry
Is it an allowed solution to have instantaneous information transfer between
distantly separated points if there was a slower-than-light bulk transfer
phase beforehand? This is the idea of physically carrying a supply of
entangled photons to Alpha Centauri, which might take a hundred years, then
enjoying your Netflix streaming in real time until they're all used up.

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weavejester
Any solution that allows for FTL transfer of information violates causality,
at least according to relativity. If you can transmit information over
entangled photons instantaneously, you can use the time dilation effects of
relativity to send information back in time to yourself.

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Mangalor
But transferring instantaneously is _theoretically_ possible through this
method, correct?

So am I right in interpreting that _if_ we can transfer particles
instantaneously, that information time travel must necessarily follow?

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nine_k
If we can transfer information FTL, (backwards) time travel necessarily
follows.

See Kip Thorne's time machine schematics (mentioned e.g. here:
[http://www.andersoninstitute.com/wormholes.html](http://www.andersoninstitute.com/wormholes.html)).
The only problem is that you need a wormhole to build it.

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renox
It's too bad that the remarks are focused on the FTL fallacy of Quantum
Teleportation instead of the innovation claimed: being able to _reliably_ do
QT _is a big improvement_ over the current methods.. If memory serves, I read
articles where they said that in their experiments, the QT was successful 20%
of the time, obviously this depends on the experience's setup, but 100%?
That's a first, AFAIK.

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api
Title of this post does not seem correct. Is this really FTL or is there an
at-light-speed signal that must also occur to convey the entangled state?

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antognini
The title, along with the rest of the article, seems to obscure an important
point. Although the entangled particles appear to communicate with each other
FTL, the _observers_ can't communicate any information with each other this
way. There are still lots of applications of this to quantum computing, but
there wouldn't be any way to build an ansible with this.

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Mangalor
Question: Is an ansible absolutely impossible for any current theorized method
in physics?

I ask in light of current research on FTL travel with alcubierre drives.

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widdma
The prohibition of faster than light travel (or communication) in GR only
applies locally. That is to say, it really should be phrased as "two observers
can not have a relative speed faster than c at the same point."

If you're not talking about the same point of space, the space between the
observers could be expanding and the rate of this expansion can legitimately
be faster than c without violating the relativity principle.

The trick to creating genuine FTL travel or communication is to somehow
multiple paths between the same points in spacetime -- i.e. a wormhole. If the
new path is shorter than the other, then information can travel along it at a
speed less than c, but still take less time than light going the long way.

Quantum entanglement whole different game. Once a measurement has been made,
the entanglement is broken and the components are left in a particular state.
But, while the observer that did the measurement knows the state of the other
component, they can only convey that information via regular, light speed,
communication.

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Someone
_" If the new path is shorter than the other, then information can travel
along it at a speed less than c, but still take less time than light going the
long way."_

If light can go through that wormhole, too, it technically wouldn't be FTL at
all, would it? Otherwise, we already have FTL travel: point a laser at a
mirror on the moon, step a meter aside, and wait for the light to finally get
there.

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strlen
Does this mean that N quantum computers can agree on the spin of an electron
instantaneously, i.e., meaning that there's nothing like FLP impossibility
result for distributed quantum computing? Or would that still imply violation
of No-Communication theorem even if the observes can't exchange any
information that way?

