Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

QM laws fundamental vs effective

  1. Apr 6, 2015 #1

    zonde

    User Avatar
    Gold Member

    I have impression that physicists consider QM laws as fundamental, meaning that there should be a way how QM mathematical form is realized in reality.

    On the other hand QM laws could be effective laws resulting from some process of evolution. In that case it should be possible to characterize QM laws by apparent purposefulness.

    Is my impression justified? - that second option is not considered.
     
  2. jcsd
  3. Apr 7, 2015 #2

    atyy

    User Avatar
    Science Advisor

    The option that QM is only an effective theory is considered by GRW and dBB. In Valentini's picture of dBB, the QM laws do result from some evolution. It may be possible to view dBB as arising from apparent purposefulness, but one would have to solve an inverse calculus of variations problem. (I was recommended to look at Enzo Tonti's work for the inverse calculus of variations problem some time ago on PF).

    http://arxiv.org/abs/quant-ph/0403034
    Dynamical Origin of Quantum Probabilities
    Antony Valentini, Hans Westman
     
    Last edited: Apr 7, 2015
  4. Apr 7, 2015 #3

    zonde

    User Avatar
    Gold Member

    I had some questions on mind and I wanted to find out if there is meaningful context in which I can ask these questions. So if you say that in context of dBB it is meaningful to ask questions about apparent purposefulness of QM laws let me ask this:
    Does it seems reasonable to say that apparent purpose of unitary evolution is to fulfill Pauli exclusion principle?
     
  5. Apr 7, 2015 #4

    bhobba

    Staff: Mentor

    Most, including me, consider them fundamental. But the fact is we simply do not know - we have interpretations where its not the case eg Primary State Diffusion.

    Thanks
    Bill
     
  6. Apr 7, 2015 #5

    bhobba

    Staff: Mentor

    Its a theorem from QM's basic axioms, nothing to do with the Pauli Exclusion Principle:
    http://arxiv.org/abs/0808.0779

    Thanks
    Bill
     
  7. Apr 7, 2015 #6

    zonde

    User Avatar
    Gold Member

    But this Primary State Diffusion interpretation still considers that quantum systems are coherent sort of "naturally", right? And in that sense they consider QM as fundamental.

    What I mean by QM not being fundamental is something like this. Quantum systems are interacting with environment constantly and so they become somewhat random. But they maintain coherence by some rather sophisticated mechanism. Sort of decoherence on it's head.
     
  8. Apr 7, 2015 #7

    bhobba

    Staff: Mentor

    I have no idea what you mean by that.

    The issue is some interpretations assume a sub-quantum world from which QM emerges as an approximation. Primary state diffusion is one example, Nelson stochastics is another, and even BM is often viewed that way.

    Of course if true there will be deviations from QM that may be able to be experimentally checked one day.

    Thanks
    Bill
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: QM laws fundamental vs effective
  1. When qm effects begin (Replies: 4)

Loading...