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Comment by phkahler | Hacker News Reader

>> Researchers teleport particle of light six kilometres

I'm sure they did nothing of the sort. At best they transferred an unknown state of a photon to another photon six kilometers away, then confirmed via measuring both.

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Not so fast.

There is a good reason to call it quantum teleportation and not quantum facsimile.

When you move matter from one place to another it moves, it's not copied. When move classical information (or state) , you can retain the original or multiply it many times.

Quantum teleport demonstrates interesing aspects of quantum information that makes it work like material thing. When information (quantum state) moves, it can't be copied (no-cloning theorem). You lose the original from the sending end just as you would lose a physical object you send to other place.

Quantum theorems like no-hiding theorem, no-deleting theorem, no-cloning theorem makes quantum information act more like material substance than classical information.

There is no physical of philosophical argument differentiate between "real" teleportation and "just moving state".

Actually, there is. Sci-fi teleportation removes something in one location, and manifests it in another. Quantum teleportation is much more like taking two human bodies (one yours, one inert) and two throw-away specially prepared human bodies, splitting them up as (you,special) somewhere and (special,inert) somewhere else, and then running a destructive read-local/write-remote operation.

In order to effect Quantum Teleportation, we run a process that literally wrecks one of the specially prepared bodies, _kills you_, and then if the second step of the process is run correctly on the other pair of bodies, wrecks the other specially prepared body and _restores you_ as you were before the cache-and-restore process, in the previously inert body.

And that's only if the second half of the process gets run correctly. It's quantum operations, so any quantum interference may disturb the system and you stay dead forever. Or, in QT terms: entanglement is lost and the information obtained is no longer correlated.

This is so far removed from what non-science considers teleportation that it is a misnomer at best, and a populist term when used outside of science at worst =)

In addition to quantum state teleportation quantum energy teleportation [1] and quantum particle teleportation is theoretically possible [2].

[1] http://www.tuhep.phys.tohoku.ac.jp/~hotta/extended-version-q...

[2] http://journals.aps.org/pre/abstract/10.1103/PhysRevE.93.066...

"When you move matter from one place to another it moves, it's not copied."

Matter is not being moved here.

"There is no physical of philosophical argument differentiate between "real" teleportation and "just moving state"."

Sure there is.

Arguably - that nothing was copied or transferred in the first place and that the particle was always in a given state until it was observed.

It does not work as material thing that is teleported. When you make measurement quantum function collapses and something that we don't know is happening and it's not teleporting anything because state is changed faster than speed of light, and no information or material can travel faster than that. This is a known paradox. Anton Zeilinger (father of quantum entanglement) is describing this in his books in more detail.

Why the assumption that teleportation means faster than light travel?

Because Anton Zeilinger has proven in his experiments that "teleportation" can happen faster than speed of light. It's what Einstein said was "spooky" about "quantum teleportation" that it contradicts theory of relativity.

Information in teleportation can't travel faster than light. Teleportation is not finished until data is transmitted at light speed.

  something that we don't know is happening

For not understanding, you sure have a closed mind about what's going on.

In other news, words can mean more than one thing.

Until someone reads them and their meanings collapse. :)

At least we have a link that point to where this comment is at any time. ;-)

We just don't have any idea where the thread is going...

We do have the HN god particle: dang. He can alter its trajectory to point towards the trash can. :)

True, but that doesn't mean you can use words that fundamentally change the meaning of the sentence and then pass it off as the same thing.

I could care less.

Clever.

Couldn't?

At the risk of being too pedantic, that's the point. The incorrect phrasing is often used to mean the original thing, when the incorrect phrasing fundamentally changes the actual meaning of the sentence.

That said, this is a chain of comments that skirts dangerously close to not-contributing IMO, since I'm not sure making cryptic comments that lead readers that don't happen to reach the right context sensitive interpretation to produce more comments asking about it aren't actually worse than a pure non sequitur, from a discussion point of view. Having a clever counter-example (as the GP does) is good. Leaving it unexplained and ambiguous is not.

For all intensive purposes

I (hopefully) see what you did there :)

Particles do not have individual identity.

https://en.wikipedia.org/wiki/Identical_particles

Since there is always some degree of uncertainty w/r/t location and velocity, there's no way to tell which particle is which over time.

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