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Researchers quantum teleport particle of light six kilometres

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Re: Researchers quantum teleport particle of light six kilometres

#91

Post by CocaKoala »

hartator wrote: post #75
3chelon wrote: post #27

10 picoseconds is "one millionth of one millionth of a second"? Damn it, I must have been misunderstanding engineering units all my life.

Is it not? https://en.wikipedia.org/wiki/Picosecond "or one millionth of one millionth of a second"

Your link says that one picosecond is one millionth of one millionth of a second.

The article itself says (or at least is written to imply) that ten picoseconds is one millionth of one millionth of a second.

Since ten is not one, one of those two statements (and definitely not ten of those two statements) must be incorrect.

Re: Researchers quantum teleport particle of light six kilometres

#92

Post by javajosh »

semi-extrinsic wrote: post #51
brazzledazzle wrote: post #42

Earlier quoted context omitted.

Is "measurement" or "observation" a simplified term for a complex process? It can't be as simple as a human "looking" at something since there's nothing special about humans (that I know of). I really wish I had the time and capability to understood how quantum entanglement really works. It seems a lot like magic if you take the layman explanations at face value.

This is a Hard Problem, to define what process is a "measurement" and what is not. But if we think about it very simply: a photon hitting a detector (or analog film strip) can be a measurement. Since this process converts quantum information to classical information (a digital or analog signal), we know that it must lose information. Only by making many measurements can we infer statistical properties of the entire q…

> Since this process converts quantum information to classical information (a digital or analog signal), we know that it must lose information. Only by making many measurements can we infer statistical properties of the entire quantum state. This is exactly what happens with the two-slit experiment.

Wow, I've never heard it explained that way. That's brilliant - did you come up with it? Interference patterns are the result of a huge number of individual photons interfering with each other at an enormous rate, and the result are laid out spatially...really lovely.

Re: Researchers quantum teleport particle of light six kilometres

#93

Post by nabla9 »

lossolo wrote: post #62
nabla9 wrote: post #54

Earlier quoted context omitted.

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 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 detai…

Why the assumption that teleportation means faster than light travel?

Re: Researchers quantum teleport particle of light six kilometres

#94

Post by paavokoya »

lossolo wrote: post #62
nabla9 wrote: post #54

Earlier quoted context omitted.

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 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 detai…

  something that we don't know is happening
For not understanding, you sure have a closed mind about what's going on.

Re: Researchers quantum teleport particle of light six kilometres

#95

Post by lisper »

MichaelBurge wrote: post #88
lisper wrote: post #81

Earlier quoted context omitted.

> What if you destroy the entanglement That is a very good idea, but doesn't work. The only way to "destroy an entanglement" is to bring the entangled particles back together. http://www.flownet.com/ron/QM.pdf or the movie version: https://www.youtube.com/watch?v=dEaecUuEqfc And if you get through those you might enjoy this one too: http://blog.rongarret.info/2014/10/parallel-universes-and-ar...

> That doesn't work. The only way to "destroy an entanglement" is to bring the entangled particles back together. Suppose a proton A is entangled with a proton B. If B hits an anti-proton C, it gets converted into pure energy(maybe light and heat?). If it's impossible to destroy entanglement, then the subsystem consisting of the light and heat must be entangled with the original particle. Observations: * The dimensio…

> the subsystem consisting of the light and heat must be entangled with the original particle

Yes. Exactly right. That is how/why decoherence happens. That is the reason the universe appears to be classical, and why the arrow of time seems to move in only one direction.

The rest of your questions are essentially asking me to teach you all of QM, and that's obviously not possible in an HN comment. You'll have to take a class or read a book.

Re: Researchers quantum teleport particle of light six kilometres

#96

Post by aji »

TheRealPomax wrote: post #83

Not quite as impressive when you know, and if you don't you should before opening this link, that "quantum teleportation" is not teleportation. It was a cool-sounding name at the time, but has nothing to do with sci-fi style teleportation: nothing disappears from one place and then shows up in another. "Quantum teleportation" is a process of information duplication using particles that already exist, and have been po…

right, "quantum teleportation" is a woefully misleading name, however this is still an impressive advancement and quantum teleportation will play a key role in wide-area quantum information networks

Re: Researchers quantum teleport particle of light six kilometres

#97

Post by nabla9 »

TheRealPomax wrote: post #90
nabla9 wrote: post #54

Earlier quoted context omitted.

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…

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 Te…

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...

Re: Researchers quantum teleport particle of light six kilometres

#98

Post by bostonpete »

lisper wrote: post #82
darawk wrote: post #78

Earlier quoted context omitted.

It is not absolutely certain. Quantum theory is an incomplete description of the physical laws of our universe, and the mechanism behind quantum teleportation is not even fully understood within the framework of that theory. So, it is most certainly not absolutely certain that FTL communication by this means is impossible, though it would be fairly surprising. The premise upon which the idea that it is impossible is…

It is as certain as anything in science. Yes, QM is incomplete, but it places hard constraints on the space of possible completions, and none of them allow FTL communications. FTL would break not only QM and relativity, but causality: it would allow you to send information backwards in time.

It seems to me that's exactly what an alien trying to keep us in the dark would say...

Re: Researchers quantum teleport particle of light six kilometres

#99

Post by duaneb »

TheRealPomax wrote: post #83

Not quite as impressive when you know, and if you don't you should before opening this link, that "quantum teleportation" is not teleportation. It was a cool-sounding name at the time, but has nothing to do with sci-fi style teleportation: nothing disappears from one place and then shows up in another. "Quantum teleportation" is a process of information duplication using particles that already exist, and have been po…

At the subatomic level, is there any real difference between information and a "thing"? Seems mostly philosophical and arbitrary at that point.

Re: Researchers quantum teleport particle of light six kilometres

#100

Post by Retr0spectrum »

Someone1234 wrote: post #15

Just to give a concept of how difficult this is: > “The challenge was to keep the photons’ arrival time synchronized to within 10 pico-seconds,” > “Since these detectors only work at temperatures less than one degree above absolute zero the equipment also included a compact cryostat,” said Tittel. The dark fiber seems like it was important for synchronizing the clocks. And while they claim this could be used for encr…

I'm really out of my depth on this topic, but I think I read that a theoretical cryptosystem could use the quantum state of a particle as a key, and perhaps this is what they are referencing.
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