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

Many Worlds and Quantum Field Theory

  1. Apr 10, 2015 #1


    Staff: Mentor

    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.

  2. jcsd
  3. Apr 10, 2015 #2


    User Avatar
    Science Advisor

    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


    User Avatar
    Science Advisor

    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


    User Avatar
    Science Advisor

    I wonder, is there any evidence that such rigorous QFT is in agreement with observations? (Perhaps vanhees71 could say something about that.)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook