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B Spooky Entanglement

  1. Jan 13, 2017 #1
    Can all types of particles be entangled? Do they have to be the same (electron/electron, etc.)
    Can more than two be entangled?
    How do you entangle in the first place?
  2. jcsd
  3. Jan 13, 2017 #2


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    Theoretically, any particle type could be entangled. They do not need to be the same type. And there can be more than 2 particle entanglement.

    How you entangle objects is a big subject of its own, and gets complicated very quickly.
  4. Jan 13, 2017 #3

    A. Neumaier

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    Yes. Even when initially unentangled, any interaction between two particles will immediately lead to entanglement.
  5. Jan 13, 2017 #4
    Yes, that's technically true even in situations where that entanglement consists of nothing more than conservation rules. But is it then fair to say that they were not entangled prior to interaction when the conservation rules still applied? Or how about forward elastic scattering of spinless particles where no particle changes its state? In fact, if they were some long term consequence of some primeval "big bang" (or many worlds history) then were they not already entangled by previous interaction -- however insignificant that entanglement may be for their state prior to interaction?

    It seems to me we are left with a choice of either (1) employ the very general idea that everything is entangled with everything else (which seems redundant for QM) or (2) reserve the concept as context-dependent for specific forms of entanglement for specific objects where the entanglement is observably significant as something more than a conservation rule but more like a superselection rule (even partial).
    Last edited: Jan 13, 2017
  6. Jan 13, 2017 #5
    From the various Professors of Physics (including Professors of Philosophy, specialising in Philosophy of Physics) I've written to about this, as well as information in different books, they've all stated everything is entangled with everything else.
  7. Jan 14, 2017 #6

    Zafa Pi

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    The end of loneliness. How so very zen.
  8. Jan 14, 2017 #7

    A. Neumaier

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    This is indeed the case, unless you prepare special initial conditions for a few degrees of freedom to which the discussion is restricted, and you ensure that, for some time, these are preserved by the interaction. Thus there is almost no freedom to choose.
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