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Many Worlds and Quantum Field Theory

  1. Apr 10, 2015 #1

    bhobba

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    I have been meaning to ask this one for a while - but never seem to get around to it.

    In MW its sometimes said it's simply the working out of the universal wave-function via Schroedinger's Equation. Of course Schroedinger's Equation is only valid non-relativistically.

    Wallace doesn't really consider it - although he considers NRQM in Fock Space. And I have read where its trivial to relativise MW.

    Maybe I am missing something, but it doesn't seem that trivial to me.

    Thanks
    Bill
     
  2. jcsd
  3. Apr 10, 2015 #2

    Demystifier

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    Even if there is no wave function in QFT, there is a quantum state (in the Hilbert space) in QFT. And usually (except perhaps in quantum gravity described by the Wheeler-DeWitt equation), this state is time dependent and satisfies a functional Schrodinger equation, which is associated with the field Hamiltonian derived from the field action. So obviously, MWI in QFT refers to this time-dependent state.
     
  4. Apr 10, 2015 #3

    atyy

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    But rigourously speaking, does the Schroedinger picture exist for relativistic QFT?

    As far as I understand, most of the rigourous QFTs (no UV cutoff, infinite volume) are constructed using the Wightman axioms, which is more the Heisenberg picture.

    I tried looking up whether the Schroedinger picture can exist for rigourous relativistic QFT, and the work seems much more recent, eg. Urs Schreiber, AQFT from n-functorial QFT, http://arxiv.org/abs/0806.1079.
     
  5. Apr 10, 2015 #4

    Demystifier

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    I wonder, is there any evidence that such rigorous QFT is in agreement with observations? (Perhaps vanhees71 could say something about that.)
     
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