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Vaccum fluctuations?

  1. Jan 9, 2008 #1
    Vaccum fluctuations???

    How to understand vaccum fluctuations mathematically without getting into the virtual particles that is so stereotypical of POP sci articles???
    Am i right in saying that the vaccum expectation value of the square of electric field is inversely proportional to the fourth power of l.
    where l is the lenght of the cube in where you are measuring the vev????
     
  2. jcsd
  3. Jan 9, 2008 #2

    olgranpappy

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    Homework Helper

    here's a simple way to put it in terms of creation/annihilation operators (with all indices/sums suppresed).

    In QED the electric field operator is given by (suppressing a bunch of indices and constants, etc):

    [itex]E\sim (a+a^\dagger)[/itex]

    where 'a' annihilates and 'a^\dagger' creates.

    then if <whatever> indicates the vacuum expectation value of 'whatever'

    [tex]
    <E>=0
    [/tex]
    but

    [tex]
    <E^2>\ne 0
    [/tex]
     
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