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Teleportation Gets a Boost
saavyone writes to tell us Yahoo! News is reporting that while teleportation may not quite be a reality yet a team of Danish scientists have raised the bar on this line of research. From the article: "The experiment involved for the first time a macroscopic atomic object containing thousands of billions of atoms. They also teleported the information a distance of half a meter but believe it can be extended further. 'Teleportation between two single atoms had been done two years ago by two teams but this was done at a distance of a fraction of a millimeter,' Polzik, of the Danish National Research Foundation Center for Quantum Optics, explained. 'Our method allows teleportation to be taken over longer distances because it involves light as the carrier of entanglement,' he added."
While I'd be fine transporting the quantum state, ect. for my new super computer laptop, you'd never get me into one of those things. I'd rather keep (the vast majority at any one time) of my atoms and subatomic particles with me.
But could you imagine if they could utilize a version of this teleportation to transfer the information to multiple places at once? Wow! That'd be a huge boon to subatomic construction technology!
Demented But Determined.
That yahoo article isn't really saying much at all. There is almost no real information on how they did it. Scientific American has a much more detailed description. http://www.sciam.com/article.cfm?chanID=sa003&arti cleID=000E9691-0261-1524-826183414B7F0000
In taking the next step, Eugene Polzik and his colleagues at the Niels Bohr Institute in Copenhagen shined a strong laser beam onto a cloud of room-temperature cesium atoms whose spins were all pointing in the same direction and fluctuating according to their given quantum state. The laser became entangled with the collective spin of the cloud, meaning that the quantum states of laser and gas shared the same amplitude but had opposite phases. The goal was to transfer, or teleport, the quantum state of a second light beam onto the cloud.
To do so, the group mixed a second, weaker laser pulse with the strong laser and split the superimposed beams into two arms. A detector in one arm measured the sum of the beams' amplitudes and a detector in the second arm measured the difference between their phases. Neither measurement disturbed the delicate entangled state between the light and cesium. But the researchers could use the results to apply a precise magnetic field to the cesium vapor that effectively canceled out the ensemble's original spin state and replaced it with one that corresponded to the polarization of the weak pulse, as they report in the 5 October Nature.
Stay sentient. Don't drink bad milk.
There's also a nice article in the Sept 30 issue of New Scientist (although this article is related to the study of bridging time-continuum in order to effectively "modify" the past).
;)
Although the article isn't a "teleportation" article, it does provide a fairly in-depth explanation of the principle and implications of entanglement. The article then takes this one step further by suggesting that if the two paths that the entangled photons took were then themselves split, but splitting the second path an additional length (using fibre optic cable), the two paths would take different time periods to complete, however by using photon detectors, it would be possible to determine which of the 2 sub-paths the entangled photons took, in spite of the fact that the 2nd entangled photon had not yet made that "choice" yet, effectively providing some form of "clairvoyance"
Using a crystal, [Univ of Innsbruck, Austria, researcher Birgit Dopfer] converted one laser beam into two so that photons in one beam were entangled with those in the other, and each pair was matched up by a circuit known as a coincidence detector. One beam passed through a double slit to a photon detector, while the other passed through a lens to a movable detector which could sense a photon in two different positions.
The movable detector is key, because in one position it effectively images the slits and measures each photon as a particle, while in the other it captures only a wave-like interference pattern. Dopfer showed that measuring a photon as a wave or a particle forced its twin in the other beam to be measured in the same way.
To use this set-up to send a signal [through time], it needs to work without a coincidence circuit. Inspired by Raymond Jensen at Notre Dame University in Indiana, [John] Cramer then proposed passing each beam through a double slit, not only to give the experimenter the choice of measuring photons as waves or particles, but also to help track photon pairs. The double slits should filter out most unentangled photons and either block or let pass both members of an entangled pair, at least in theory. So a photon arriving at one detector should have its twin appear at the other.
[snippety snip]
His extra twist is to run the photons you choose how to measure through several km of coiled-up fibre-optic cable, thereby delaying them by microseconds. This delay means that the other beam will arrive at its detector before you make your choice. However, since the rules of quantum mechanics are indifferent to the timings of measurements, the state of the other beam should correspond to how you choose to measure the delayed beam. The effect of your choice can be seen, in principle, before you have even made it! That's the idea anyway.
This process allows you to copy quantum information from one set of atoms to another without measuring it, and thereby destroying it.
If you can't measure it in the first place (and the original gets destroyed in the process), how do you know that what you end up with is a copy ?
Every time someone mentions the soul issue I quote some scriptures on it and get modded bigtime offtopic or flamebait. It's late but here's a few from memory.
... some bible translations will use the phrase "dead body" or "corpse" to make it clear to our modern ears.
Numbers 6:6 literally states "do not touch a dead soul"
Genesis 2:7 "the man became a living soul"
Also Ge. 2:19 explains that as each animal or "living soul" would come to Adam he would name them. Ge. 1:20 the waters swarmed forth full of "living souls".
Etc, etc...
Doesn't take too much research to find out that the Hebrew word for "soul" is related to breathing... basically any animal that breathes is a "soul". A living being. Ezekiel 18:4 explains that the "soul" who sins shall die. It means person. You ARE a soul, you don't have one.
Cwm, fjord-bank glyphs vext quiz
So what is it about people, rocks, or other tangible objects that cannot be described as information? You are information much more than you are something tangible - pretty much every atom in you will migrate out of you at some point, and you're almost completely different to what you were 5 years ago. It's the information that is important. Actually, quantum teleportation is a method for replicating matter in a remote place (because the only sensible definition of replication is reproducing every facet of the originals state). The only reason nobody has used it yet to teleport a human is because it currently only works on very simple and small structures over distances too small to be useful.
The advancement of quantum teleportation is that in the past, we could only enocode and then transfer information that we could measure (I mean you could transfer the information by walking but that's not the point). You can't measure quantum information without ruining it, so until quantum teleportation we could not transfer quantum information from one place to another. Whether or not you even need to transfer the quantum information to transfer a person is an entirely different question. Would it matter if you just made a classical copy of a human? Maybe not - maybe you would get the same person, but I think everyone would be more comfortable with the process if there was absolutely no information lost, no matter how nebulous.
This almost certainly will not replace optic fibre for long distance communication, because there is very little communication that requires the transmission of quantum information. We generally want to transfer classical information.
Speaking of teleportation, one of the best SF novels about someone who could teleport is "Jumper" by Stephen Gould. It's presently out of print, but won't be much longer once the movie comes out next year. Try to read it before the movie will probably ruin it. Review here: http://www.lostbooks.org/guestreviews/2001-07-06-2 .html