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Electon-positron question

  1. Oct 29, 2005 #1
    i read QED the other day, and was wondering, is the idea that a positron is an electron travelling backwards in time still generally accepted?? cos i know he gave the lectures a while back, and lots of things have changed since then, but it stuck me as an interesting concept.




    p.s. i may have put this in the wrong forum again. sorry if i did.:blushing:
     
  2. jcsd
  3. Oct 30, 2005 #2

    Astronuc

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  4. Oct 30, 2005 #3
    is it only in the context of Feynamn diagrams? is it because they use space and time? or can you use it in the 'real' world as well?
     
  5. Oct 30, 2005 #4

    Astronuc

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  6. Oct 30, 2005 #5

    Physics Monkey

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    Hi guys,

    The statement that particles traveling backwards in time correspond to antiparticles traveling forwards in time is a valid one. In fact, some of the greats, like Feynman, preferred the evocative language of electrons moving forward and backward in time, but mostly now days people prefer to talk about electrons and positrons all moving forward in time. The two are equivalent, however.
     
    Last edited: Oct 30, 2005
  7. Oct 30, 2005 #6

    Astronuc

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    It's definitely not a concept I use everyday as an engineer, and I have been away from academia for awhile, so I am not familiar with what is being taught in the advanced physics courses.

    Thanks, Physics Monkey!
     
  8. Oct 31, 2005 #7

    dextercioby

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    QED is not only CPT invariant, but also CT invariant. This means that scattering experiments (for example) are identical if time "flew" backwards and all electrons became positrons at the same time.

    Daniel.
     
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