Slashdot Mirror

← Back to Stories (view on slashdot.org)

Beginner's Guide to Quantum Entanglement

Posted by Zonk on from the in-case-you-need-to-make-your-own-universe dept.

No Fortune writes "Einstein called it 'Spooky action at a distance.' This article describes, in scientific layman's terms, how spooky action is created." From the article: "Normally the photons exit the crystal such that one is aligned in a horizontally (H) polarized light cone, the other aligned vertically (V). By adjusting the experiment, the horizontal and vertical light cones can be made to overlap. Even though the polarization of the individual photons is unknown, the nature of quantum mechanics demands they differ."

7 of 186 comments (clear)

  1. Jesus Zonk... by grasshoppa · · Score: 5, Funny

    ...what the hell is the matter with you anyway?

    Throwing that kind of physics at us on a Saturday evening when you *know* most of us are half drunk?

    Bastard.

    --
    Mod me down with all of your hatred and your journey towards the dark side will be complete!
  2. Zonk is Jesus?! by Anonymous Coward · · Score: 5, Funny

    Lord help us... but anyway, you've got be half-drunk to even start getting quantum physics. Everyone knows that... well, they do when you ask, they didn't before you asked.

  3. In what? by Transcendent · · Score: 5, Funny

    in scientific layman's terms

    Ah, oxymoron terms... the best kind.

  4. Great Article! by CynicalGuy · · Score: 5, Funny

    +1 dugg

  5. Re:"Quantum Entanglement"? by Tablizer · · Score: 5, Funny

    Is that what the geek kids are calling it these days?

    Call it whatever the hell you want; geeks still won't get any.

    --
    Table-ized A.I.
  6. Re:Weird thought by Y2 · · Score: 5, Informative
    Suppose that at the instant you stopped it, the coin was horizontal. You now know that, at that particular instant, the second coin was vertical

    Sorry, no. If the coins aren't at the same place, then this term "at that particular instant" is not well defined.

    The tantalizing notions of instant communication involve choosing which of two or more possible measurements to make on one of the photons (after they are separated) and the effects of that choice on the possible outcomes of a fixed or independently-chosen experiment on the other photon. Google "EPR Paradox" for a primer.

    --
    "But all your emitter and collector are belong to me!"
  7. Re:Someone link me to an explanation? by PaSTE · · Score: 5, Informative
    Actually, what you've hit upon is something called the "hidden variables" theory of quantum mechanics. For a while after the spookiness of entanglement was figured out, vis. the Einstein-Podolsky-Rosen paradox, many physicists thought just like you do--that there was some hidden variable within the system that we could not measure, but which determined the state of the system exactly. They figured for instance that, if a certain decay process produced two photons, one left-polarized and one right-polarized, then there was some feature of the decay which determined which othe the photons is left-polarized and which right-polarized, so that our measurement of one did not "change the state" of the other photon, if merely revealed its pre-determined polarization.

    The hidden variables theory of quantum mechanics was disproven by a physicists named John Bell. In his method, he began by assuming that these "hidden variables" existed, then, using geometric arguments and the postulates of quantum mechanics, derived a set of inequalities which showed no physical theory of local hidden variables can ever reproduce all of the predictions of quantum mechanics.

    It's not intuitive at all, but Bell's argument is sound. Entanglement and action-at-a-distance is real, and not due to the system's state being pre-determined by hidden variables.

    --
    /*No comment*/ #No comment //No comment ;No comment 'No comment REM No comment !No