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What's between particles

  1. Sep 1, 2005 #21
    No they are not wavefunctions, they are field operators. This is the whole point of this thread.

    marlon
     
  2. Sep 1, 2005 #22

    samalkhaiat

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    The field operators, or operator-valued distributions to be precise, need a wave function to act on, "they don't just play with the kids in the back garden".
    Have you heard about [in> & [out> states? Do you know any thing about the FOCK SPACE in quantum field theory? elements of this space are wave functions for the quantum fields.These subjects are well presented in the book;
    "Quantum field theory of point particles & strings" (chapter11) 1992, Addison Wesley, frontiers in physics. have a look at it if you have good mathematical background.
     
  3. Sep 2, 2005 #23
    field operators act upon fields, not wavefunctions. You are missing the difference between QFT and QM (and i am not talking about special relativity here :wink: )

    Yes i have, how do you think these are described ?

    fields arise from wavefunctions. i never said this was not he case. as a matter of fact, i have mentioned this several times when trying to outline the difference between them.

    In QFT, particles are described by field-excitations, which does not occur in QM. This Fock example (in QFT) is no exception to this.

    Besides, would you describe quarks in terms of Fock space ? I do not think you would be using gluons in that case...

    marlon
     
  4. Sep 2, 2005 #24

    samalkhaiat

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    This is for marlon; I am sorry sir, I think you need to do alot of reading & studding. Try BRAIAN HATFIELD's BOOK (THE ONE I MENTIONED BEFORE) it is avery good book.
    or the all time classic on QFT; introduction to the theory of quantized fields, by
    BOGOLIUBOV & SHIRKOV.
     
  5. Sep 3, 2005 #25
    I will do the reading, but what is "studding"

    i know this book very well and whatever you say about wavefunctions versus fields is not in there.

    This is a bit ironic, since i have been explaining this stuff many times here. Then, up comes a new dude with totally different (read : wrong) ideas on this...But anyway, i suggest you read entry nr 40 on https://www.physicsforums.com/journal.php?s=&action=view&journalid=13790&perpage=10&page=7 [Broken] in the link.

    marlon

    ps or read QFT in a Nutshell by Zee, or read Peskin, Weinberg,...
     
    Last edited by a moderator: May 2, 2017
  6. Sep 3, 2005 #26

    HallsofIvy

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    I'm willing to do the "studding"!
     
  7. Sep 3, 2005 #27

    samalkhaiat

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    This Is For Marlon & The Other Person

    sorry for the miskeying,I meant to write studying.I thought such mistake isn't as hard to comprehend as the rule of wavefunction in QFT.So you know BOG. & SHIR.'S book.Then goto page 93,you will read "...this expectation value may
    be calculated from the.....with the aid of the transformed STATE AMPLITUDES
    .."In this book wavefunction is called state amplitude,which is one of many na
    mes(the eigen state,state-vector,the probability amplitude & others),page 93
    isn't the only page in this book which mention wavefunctions, Try any of the 720 page, and you almost certainly find reference to wavefunction. You must
    know that expectation value is nothing but operator sandwiched between wav
    efunctions, If you dont know that, then learn this; IF THE PHYSICS IS QUANT
    UM PHYSICS, THEN THERE IS WAVEFUNCTION TO WORK WITH.
    As for S Wienberg's book that you mentioned, here it is in my hand right now,
    so let us open it & read something(VOL I), OK on page 170, oh how nice "Equi
    valently,this could be stated as a condition on the ''wave functions'', the coef
    ficients of these ''multi-particle base vectors'' in physically allowable state-vec
    tors."
     
  8. Sep 3, 2005 #28

    samalkhaiat

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    this is for marlon 2

    Now let us go to page 173 the second paragraph; "... the N-particle state can be obtained by acting on the VACUUM with N creation operators," . Page
    288 on FEYNMAN RULES; "...are 'in' and 'out' EIGENSTATES of the full Hamiltonian " Yet more names for wavefunction the [in> , [out> & the N-partcle state AND dont forget the VACUUM STATE.
    I SUGGEST YOU READ WIENBERG's BOOK, AND THEN AND ONLY THEN (IF YOU CAN ACCESS THE UNIVERSITY OF LONDON THESIS ARCHIVES), YOU CAN READ THIS "NEW DUDE"'s THESIS UNDER THE TITLE

    INVARIANCE, CONSERVED QUANTITIES & FIELDS .

    PHYS DEPART, BIRKBECK COLLEGE 1995.

    I REST MY CASE ABOUT THE SUBJECT

    THANKS
     
  9. Sep 4, 2005 #29
    :rofl: :rofl: :rofl: :rofl:
    i am sure you will do a great job at it


    marlon

    "Just because there is some analogy between two concepts does NOT imply they are the same"

    "copy/pasting some random extracts from a book does not qualify as proof"
     
    Last edited: Sep 4, 2005
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