Sticky Quanta

Discussion in 'Astronomy, Exobiology, & Cosmology' started by esp, Nov 30, 2001.

  1. esp Registered Senior Member

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    Has anyone heard of something called Quantum Entanglement in relation to the teleportation of light?
     
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  3. James R Just this guy, you know? Staff Member

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  5. Hevene Registered Senior Member

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    explain please....
     
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  7. Crisp Gone 4ever Registered Senior Member

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    When scientsists speak about quantum entanglement, they talk about a special relation between the quantummechanical parameters of elementary particles. Under some circumstances, you can couple two particles in a way they behave exactly the same way on a quantum level, so in that sence they're an exact quantummechanical copy of eachother.

    On the teleportation of light with quantum entanglement: when you have two photons (seperated at a distance of let's say 100 meters), and use/abuse the entanglement properties to give them the same quantumparameters, then you've created an exact copy of the first photon (being the second photon with the new quantum properties). Since determining the properties of a photon requires destroying it, you could say that you teleported one photon to the other.

    Let me add that quantum entanglement is a very new subject and still not well understood. At the moment it just seems to be a new mysterious connection between particles.

    Bye!

    Crisp
     
  8. James R Just this guy, you know? Staff Member

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    Hmm... not exactly, crisp.

    Quantum entanglement is a quantum relationship between two particles which can be maintained over a distance. For example, it is possible to produce pairs of particles whose spins are entangled in such a way that if one particle is found to have spin "up", say, the other will always be found to have spin "down". This relationship is maintained even when the particles are separated by large distances. However, which of the two particles has spin "up", say, is not determined until a quantum "measurement" is made on either of the particles. When such a measurement is made, the spins of <b>both</b> particles become fixed. This can happen faster than the time it would take light to travel from the measured particle to the other particle. So, even though the second particle cannot "know" in a classical sense whether its partner has spin up or down, it will always settle into the opposite spin.

    The idea of entanglement has been around since the foundations of quantum mechanics were laid back in the 1920s-1930s.
     
  9. Stryder Keeper of "good" ideas. Valued Senior Member

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    Crisp

    At present it's perceived that you destroy a "copy" while the original transport. But recently I've come up with an idea of something similar to an elastic band systematic.

    At first your band is in the "original position" and you decided to "transport" it, between the point it leaves and the point it arrives it stretches. Which basically means that its quanta lowers at the point it's being transported from while it increases at arrival, eventually the band exists at the destination. With no copies or destroyed copies.

    I wish there was a better way to explain it.
     
  10. amraam Registered Member

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    AIP article

    I source this from a release by the American Institute of Physics:

    SUREFIRE QUANTUM ENTANGLEMENT, the ability to interlink two quantum particles with practically 100% certainty, has been achieved by a NIST group (Quentin Turchette, 303- 497-3328), advancing hopes for ultrapowerful quantum computers. Previously, physicists obtained entangled particles as a byproduct of some random or probabilistic process, such as the production of two correlated photons that occasionally occurs when a single photon passes through a special crystal. Receiving entangled pairs in this way is fine for tests of quantum nonlocality (Update 399), but entangling a large number of quantum particles--essential for building a practical quantum computer--becomes much less likely if it is dependent on a probabilistic process. In their "deterministic entanglement" process, the NIST researchers trap a pair of beryllium ions in a magnetic field. Using a predetermined sequence of laser pulses, they entangle one ion's internal spin to its external motion, and then entangle the motion to the spin of the other atom. The group believes that it will be able to entangle multiple ions with this process. (Turchette et al., Physical Review Letters, 26 October 1998.)
     
  11. Crisp Gone 4ever Registered Senior Member

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    Hi James R,

    Yes, I agree. But in the case of photons, which have spin 0, two entangled photons would be identical to eachother

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    .

    Bye!

    Crisp
     
  12. esp Registered Senior Member

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    Crisp, James R, Stryder, Amraam,

    Thanx a lot guys,
    much help.

    Cheers, ESP
     
  13. James R Just this guy, you know? Staff Member

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    Um... crisp.

    Photons have spin 1.
     
  14. Crisp Gone 4ever Registered Senior Member

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    Hi James R,

    Ofcourse they have. How in earth did it ever get into my mind that photons have spin 0.... I guess alcohol and science don't go together after all

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    Bye!

    Crisp
     

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