Improvements in Teleportation

assaultriflesforfree writes "Here's a little update on quantum entanglement and teleportation from The New York Times (free registration, yay): 'Employing a facet of quantum mechanics that Albert Einstein called "spooky action at a distance," scientists have taken particles of light, destroyed them and then resurrected copies more than a mile away.' I am a little skeptical about the Heisenberg Uncertainty Principle statements, though. Is this really a form of Star Trek's Heisenberg Compensator?"

Comments

Without registration...

[Anonymous Coward]

Here's an article from National Geographic that doesn't require registration. Sorry I couldn't find the Google News link for the NYT article.

(from Anonymous Karma Whores R Us)

No Reg. Required

[Anonymous Coward]

Light Particles Are Duplicated More Than a Mile Away Along Fiber
By KENNETH CHANG

Employing a facet of quantum mechanics that Albert Einstein called "spooky action at a distance," scientists have taken particles of light, destroyed them and then resurrected copies more than a mile away.

Previous experiments in so-called quantum teleportation moved particles of light about a yard. The findings could aid the sending of unbreakable coded messages, which is limited to a few tens of miles.

The new experiment used longer wavelengths of light than earlier ones, letting the scientists copy the light through standard glass fiber found in fiber optic cables.

"The central issue is to move to telecom fibers and telecom wavelengths and telecom technology," said Dr. Nicolas Gisin, a physics professor at the University of Geneva and the senior author of an article today in the journal Nature. "This then allows us to go the long distance."

The experiments are a primitive realization of the transporter in the "Star Trek" television series that beams people from starship to planet. In coming years, it may be possible to use teleportation to imprint the exact quantum configuration of one atom to another. But teleporting something from the everyday world like a person that contains more than a trillion trillion atoms is highly unlikely, if not impossible.

Even with the light particles, photons, about one in a thousand were received at the other side.

"You're not very sure to arrive," a researcher, Dr. Hugo Zbinden, said about human teleportation.

Still, the experiments show that scientists can overcome a seemingly insurmountable conceptual barrier, the Heisenberg uncertainty principle. The principle states that the location and velocity of a particle cannot both be precisely measured at the same time. That would seem to make it impossible to teleport anything, even single particles, because without knowing their exact specifications they cannot be copied somewhere else.

Devised in 1993 by scientists led by Dr. Charles H. Bennett of the I.B.M. Thomas J. Watson Research Center in Yorktown Heights, N.Y., quantum teleportation produces pairs of "entangled" light particles that can be thought of as a pair of encoding and decoding rings. A message is combined with the encoding light particle. That combination goes to the recipient, who uses the decoding photon to decipher the message. Because no one else has the decoding photon, no one else can decipher the message.

Other encoding techniques using quantum cryptography are simpler, and a more immediate use for teleportation would be as a repeater. Photons almost all peter out after traveling about 50 miles through optical fiber. Teleportation would enable the creation of copies every 50 miles or so, letting the message be sent across an unlimited distance.

0.0 latency gaming anyone?

[ageOfWWIV]

The potential application of this technology is boundless. Everything from communication to transportation, even society will be changed by the refinment and eventual mastery of this particular branch of quantum physics.

I'm sure 400 years from now people will be using spooky action at a distance to teleport to their flying cars so they can head out to stores to finally buy a shrinkwrapped copy of Duke Nukem Forever.

don't beam ME up.

[MoFoYa]

Teleporting light - ok
Teleporting an object with considerable mass - ok

NOT me though. What do you think might happen to you between the time you are destroyed and the time your mass is replicated?
I would think that even if it were a very short time there would still be problems -- after all you WERE destroyed.

On the good side - imagine a future when you can purchase something online and have it in 5 min. by replicating it in your new replicator(duh) thats connected directly to your computer. You buy the item - then download the mass profile(perhaps a .mpr file) and send it to the replicator like you would a document to a printer.
- very cool stuff

Re:don't beam ME up.

[pkaral]

If you are destroyed and then replicated, you are effectively dead.
...
So basically we concluded that teleporting an object by replication/destruction would be helpful to everyone except the object in question.

Not necessarily. You assume that there is a "real me" and a "copy-of-me". However, if the replication process is perfect, then both the individuals that come out of the other end will for all practical purposes be me - look like me, feel like me, think like me, remember the things I remember and all of the other characteristics that together constitute me.

The crux is, as you point out, the destruction of "the original copy" in the teleportation process. The implicit point in your argument is that the death of one of the copies matters. My question to that point is: To whom? Me-before-the-teleportation doesn't care - I will live on in the copy. The teleported copy is alive, so it doesn't matter to it. "The original copy" is "dead", and didn't mind before it happened.

So it all ends up being very philosophical: Does it matter to be dead per se, or is it the absence of a continued existence (such as in the form of a copy) that is wrong about being dead? I would say the latter, and therefore you may teleport me as soon as your device is 99,99999% secure (or even less, if the destination is an exiting place).

Photons VERY different from massive particles

[DrLudicrous]

Photons are massless particles. They are part of a large class of particles known as bosons. All particles are either bosons or fermions. Most massive particles with which we are familiar are fermions. These include electrons, neutrons, and protons, the basic building blocks of matter. Quarks too. Bosons are the particles that mediate the four forces between the fermions. Photons, for instance, are the carrier of the electromagnetic interaction. Gravitons are the bosons that give rise to the gravitational interaction.

My point? It is one thing to teleport a photon, which is a massless boson. It is quite another thing to teleport a massive fermion, let alone a collection of them as would be found in any massive object of appreciable size. The physics of teleportation would most likely be very different, since the quantum mechanics and statistics of bosons are quite different from those of fermions. So don't get your hopes up yet regarding teleportation a la Star Trek.

Quantum Teleportation

[Karhgath]

Ok, before everyone freaks, Quantum Teleportation isn't what most think it is. I've had a class and attended a few lectures by renowned Gilles Brassard from the University of Montreal, one of the founder of the field and especially quantum encryption, along with Charles H. Bennet from IBM and many others.

First, "teleportation" only teleports "DATA", quantum information, like the spin of an electron. You won't see any beam me up scotty, despite how much people wants to and how wrong reporters are in artciles =)

Second, here's a VERY brief info page on Quantum Teleportation on IBM's page:

http://www.research.ibm.com/quantuminfo/teleport at ion/

For more in depth info, try to find articles in magazines and books, especially one written by Charles H. Bennet and/or Gilles Brassard.

One lecture by Brassard can be found online here, there's even a PDF:

http://www.msri.org/publications/ln/msri/2002/qu an tumintro/brassard/2/

They will explain this much better than my understanding will do. It's MUCH funnier and interesting when Brassard presents it, and it's MUCH harder to understand too. The few pictures and bits at the begining of the lecture are what Quantum Teleportation is NOT. Even renowned scientific publication are fooled by bad journalism, and even IBM went over it's head with this, it's kinda funny =)

Anyway, "Beam me up Scotty" will never result from Quantum Teleportation, so don't hold your breath =) The article briefly states this tho, but only seems to gloss over it and even says "maybe", which is completely wrong.

Also, Brassard stated MANY times that is does not violate ANYTHING, and especially not Heisenberg uncertainty principle. The original DATA must be destroy, then it is "rebuilt" on the other side, and because of a property of EPR, "entanglement", you never mesure the quantum information completely, thus not violating Heisenberg uncertainty principle.

One last note, the following bit on the article is probably the most simplistic non-explanation of what is Quantum Teleportation:

"A message is combined with the encoding light particle. That combination goes to the recipient, who uses the decoding photon to decipher the message. Because no one else has the decoding photon, no one else can decipher the message."

Re:Hidden variables

[Kibo]

Man did that bad analogy get out of control.

Anyway. I think the idea behind the cat was to show the absurdity of an indeterminate state like something being both spin up and spin down. Under the copenhagen interpritation it doesn't really matter what the inscrutible secret reality is, but many extremely clever experiments have shown repeatedly, and perhaps most dramatically in investigations of 'spooky action at a distance', that the universe really is that wierd. The thought experiment is wrong, because, for the most part, that quantum nature were discussing disintigrates as things get bigger. The cat wouldn't be alive and dead, the cyanide wouldn't be contained and released, the vial smasher wouldn't have spared and smashed the vial, and radioactive particle will either have decayed or not. It might 'think' about it in a maelstrom of virtual particles, but once it decays, it quickly joins the larger system. And before you know it PETA is suing your ass. I think this particular thought experiment remains popular because it spotlights a flaw in our intuition, and how we interpret uncertainty.

If you're religious you can believe god watching the universe is what makes it go, if you're a Kari Wurher fan maybe there's an alternate universe where she'll rub up against you, or, if you're like me, you favor decoherenece (not that I wouldn't favor Kari). It's just important to remember these comfortable ways of framing or describing what's happening aren't nessecarily what's acctually happening where we aren't allowed to look.