Hi, i can't get the result stated as equation (2.33) in page 22. To be more clear, after the elimination of the divergent commutator, i still have two extra terms that i don't know how to cancel out. the total extra term is ap.a(-p)-a^+(-p).a^+p.(adsbygoogle = window.adsbygoogle || []).push({});

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# Calculation in Peskin&Schroeder QFT book

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