
Researchers have successfully teleported wave packets of light - Urgo
http://www.abc.net.au/news/stories/2011/04/15/3192505.htm
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gregschlom
One thing that isn't clear in this article is whether they really teleportated
it, meaning that they were able to transfer information _instantaneously_ from
point A to point B (which would go against Einstein's relativity law that
states that nothing can go faster than the speed of light), or if they just
transported a light beam from one point to another with regular means of
communication.

It sounds more like it's the later case, and the word "teleportation" here is
probably more a link bait than anything else.

And in any case, the title in the article is horrible: "Scientists teleport
Schrodinger's cat"

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baddox
The speed limit of the universe isn't just some hypothesis waiting to be
disproven. It can't be broken. It's impossible.

~~~
arethuza
Scientific theories aren't reality - they are a _model_ of reality and to be
considered scientific a theory has to be refutable - if you can't conceive of
experimental results that would disprove your theory then it's not really a
scientific theory.

So _every_ scientific theory is in a very real sense "waiting to be
disproven".

~~~
baddox
We can know things. We know that no algorithm can determine whether or not
arbitrary Turing machines will halt, because assuming the contrary leads to a
contradiction. Similarly, no consistent axiomatic system powerful enough to
express propositions of elementary arithmetic can be complete.

Neither the undecidability of the halting problem nor Gödel's first
incompleteness theorem are "waiting to be disproven." Similarly, the speed
limit of the universe, if assumed to be breakable, leads to all sorts of
contradictions and true paradoxes. Note that I'm _not_ saying that the
entirety of some theory, be it special or general relativity, quantum theory,
etc. are known truths.

~~~
lobster_johnson
Algorithms, being a sub-branch of mathematics, are logical constructs, which
means they can be proved or disproved on a logical basis. Physics is a
scientific model of reality which is based on experimental observations
(mathematics is used as a descriptive language, but the underlying reality
itself is not (as far as we know) based on logic), therefore any physical
theory is not provable, only verifiable through experiment to some statistical
probability of correctness. The current physics theory is backed by a huge
amount of observations, so admittedly we can be pretty sure about much of the
theory. But to say that we "know" is not correct.

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Saavedro
A better word for non-quantum-physicists would be "transport" here. It's very
difficult to move quantum bits from one place to another at all. The light
beam is used to increase the reliability of that process.

This doesn't affect how -classical- information is transmitted or make it any
better. It makes -quantum- information transmission reliable, which is
actually pretty significant. This should allow for quantum computers of larger
sizes than the super-tiny ones that have been created so far to actually work.

<http://en.wikipedia.org/wiki/No-teleportation_theorem> (why it is difficult
to transmit quantum information)

<http://en.wikipedia.org/wiki/Quantum_teleportation> (what is being done in
this experiment) What the breakthrough is is a way to do quantum telportation
reliably -and- quickly (which had both been done before)

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bmunro
Why are people assuming that 'teleportation' means instantaneous travel?

To me, teleporting has always meant transferring the information that
describes an object to another location, where the object is reproduced. This
transfer of information occurs via light/radio waves or similar.

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jerf
I hate to post what is nearly a "me too", but I'd also like to ask that
question, with the clarification that I do not mean it as a rhetorical
equivalent of "No, of course it's not instantaneous, duh", I am genuinely
curious where the sheer confidence of the definition of "teleportation" as
"instantaneous in violation of relativity" suddenly came from. Is there some
scifi show on TV that I'm not watching that is promulgating this
interpretation or something? I've seen the belief that entanglement can be
used for FTL communication going back unto yea the very beginnings of the
internet but this solid and shared definition of instantaneous is new to me
vs. even the iteration of this whole argument I saw a few months ago. (Fringe
maybe? Haven't started that yet.)

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terandle
Not sure how anyone could of missed the whole teleport = instantaneous
thing... Thankfully Wikipedia is here to save the day!
[http://en.wikipedia.org/wiki/List_of_fiction_containing_tele...](http://en.wikipedia.org/wiki/List_of_fiction_containing_teleportation)

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jerf
I have had this conversation twice a year for the past ten to fifteen years.
Something needs to have _changed_ , because the conversation has changed in
the way I cited. The vast bulk of those don't even address whether it's
"instantaneous" in violation of lightspeed because they just ignore lightspeed
entirely. You in fact seem to be reinforcing my point by the casual assumption
that teleportation _must_ be instantaneous-as-FTL by the very definition of
the word, and thus the mere fact that the word is used proves your point
(circularly, I might add), so let me ask you: Where did you get that idea?
It's not the way the word has been defined for the past 50 years, it's a new
mutation. Why do you think that? (And why would English have such a rigid,
useless definition for a word like that?)

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Blunt
Teleportation is a misnomer here. Nothing is being teleported or transmitted
rather information is being measured in two different locations simultaneously
as if it were teleported. What I believe is that information is showing up in
two different locations simultaneously. This term, entanglement, I think means
that every quantum spin has an equal and opposite quantum spin at some other
location that always exists. In other words, there's an opposite "thing" of
our "thing" and when we adjust our "thing" we can now see or measure the
opposite "thing" adjusting oppositely.

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CoffeeDregs
So what's the meaning here? I've been reading similar (to a non quantum
physicist) stories for years and RTFA. What will this change about my life?

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fragsworth
Minimum round trip time between San Francisco and Tokyo is about 60ms due to
the speed of light, which means in practice FPS games are unplayable across
the ocean.

If they manage to implement this shit, we'll be able to have FPS games hosted
anywhere in the world!

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burgerbrain
If we could actually break causality, playing games would be the last thing on
our minds.

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sp332
If causality is broken, how do you know it wasn't the _first_ thing on our
minds? :P

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hammock
Can anyone explain what quantum teleportation is? Wikipedia does not help,
aside from assuring me that it is not what I thought it was:

 _Quantum teleportation, or entanglement-assisted teleportation, is a process
by which a qubit (the basic unit of quantum information) can be transmitted
exactly (in principle) from one location to another, without the qubit being
transmitted through the intervening space. It is useful for quantum
communication and computation. It does not transport the system itself, nor
does it allow communication of information at superluminal (faster than light)
speed. Neither does it concern rearranging the particles of a macroscopic
object to copy the form of another object._

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teej
I found it best described as such: you put a white marble and a black marble
in separate paper bags. You send one to a friend. As soon as you open the bag,
you instantaneously know what color the other marble is. That doesn't mean you
can instantaneously communicate with your friend.

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hanibash
I'll try to explain from what I understood in quantum physics class years ago.

When you're dealing with things on the quantum level, observing a particle
affects it. Remember Schrodinger's cat? The cat is both dead and alive, until
someone opens the box. The opening of the box gives the cat its new state of
deadness or aliveness.

Quantum teleportation works through entangled particles. Entangled particles
are, in some sense, the same particle in two places. An action on one
entangled particle will instantly affect the other particle, including
observation of the particle.

Suppose Alice and Bob share an entangled particle. Alice observes the particle
on her end, collapsing it into one of four states. Which state it collapses
into is and always will be completely random.

Bob's particle was instantaneously affected in one of four ways corresponding
to those states. Trouble is, he doesn't know which way, and he can't do
anything with his particle until he does.

Alice has to communicate to Bob in any regular way, through light, telephone
or internet, what she observed on her end, so that Bob knows what exactly
happened to his particle, and what to do with it.

So in this way, it really was instantaneous over a distance, but at the same
time nothing useful happened faster than the speed of light.

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tyng
Can someone please explain what the term "teleport" mean here? I'm not getting
why this is an amazing scientific breakthrough (but I'd love to learn why it
is).

If it doesn't mean information travelling instantaneously or faster than
light, then did the reporter (or the scientist) put the word "teleport" in the
title just so it's attention grabbing?!

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tehwalrus
Anyone found the DOI link yet? The explanation in the article is, I agree,
awful, and I want to read what they actually did! If it was only moving a bit
of information from RAM to a register (or the quantum equivalent) which it
sounds like...then yea, no biggie.

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raheemm
And this is why science is hard to report on

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fragsworth
Does this conflict with the notion of the speed of light being a universal
maximum speed? If teleporting information causes bi-directional communication
to be instant, aren't signals being propagated at faster than the speed of
light?

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sorbus
It's not instantaneous; there's no conflict, no FTL to see here.

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victorantos
chinese dit it even over the air last year, distance - 16 km
<http://www.physorg.com/news193551675.html>

so what's new?

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CamperBob
I, uh, recognize the Hammond 1590D box. Do I get partial credit?

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bradharper
The damn cat was not both alive and dead simultaneously...

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guelo
I have no idea what that experiment does but the pic is cool!

EDIT: The pic is not cool?

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sorbus
Downvotes probably due to people thinking that your comment adds nothing to
the conversation, not necessarily disagreeing with you (I would think that the
pic would be cooler if it were higher res; as it is, I can't make much sense
of it).

~~~
nicklovescode
<http://www.abc.net.au/reslib/201104/r751650_6238699.jpg>

reasonably high res

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metageek
(a) So, what, those are optics they use to bounce the beam around, so they can
get 10km of laser beam on a 5m bench?

(b) I can't look at that picture without thinking of Agatha's dingbots from
_Girl Genius._ <http://www.girlgeniusonline.com/comic.php?date=20091005>

