I recently read an author making the following argument in QFT:(adsbygoogle = window.adsbygoogle || []).push({});

if <m|A^0(t,0)|n>=B then <m|A^mu(t,0)|n>=(B/p^0)*p^mu by Lorentz invariance. Can anybody tell me under which circumstances this holds and how it comes about? I understand that <m|A^mu(t,0)|n> had to transform as a 4-vector but why should it be the momentum 4-vector?

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# Another one on Lorentz Invariance

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