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Collapses, Quantum Jumps, and the Born interpretation

  1. Aug 27, 2015 #1


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    In my mind they are all the same.

    But some serious physicists (Schlosshauer, for example) claim there is no evidence for the existence of collapse.

    What about Lyman alpha emission, where an electron in a hydrogen atom “jumps” from level two to level one and emits a photon?

    Or the photoionization effect, or a Stern Gerlach experiment?

    Those all seem to me to be very obvious demonstrations of the existence of collapse.

    What am I missing?

    Or what would the no-collapse people reply?
  2. jcsd
  3. Aug 27, 2015 #2


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    The no-collapse people are perhaps many worlds people who claim that nothing actually jumped at all because all possibilities co-exist in parallel worlds together.

    IMHO this is many-words, non-sense, but it seems a lot of people find it intellectually satisfying.
  4. Aug 27, 2015 #3


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    The short answer is that all those phenomena are explained with different mechanisms in different interpretations.

    For many worlds, they are explained via entanglement and decoherence. The Stern-Gerlacch system evolves into a superposition of the electron having gone up w/ the instrument reading "electron went up" and the electron having gone down w/ the instrument reading "electron went down". The two branches don't interfere with each other thereafter because the environment acts as a massive heat/information sponge (... until we saturate the available capacity and hit heat death), creating thermodynamically uneraseable differences. Non-interfering branches look classical-ish.
  5. Aug 27, 2015 #4


    Staff: Mentor

    Actually collapse isn't part of the QM formalism - just some interpretations.

    I think MW is nonsense as well. But having studied Wallaces book mathematically its very elegant and beautiful..

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