QFT Peskin p.30 eqn 2.54
Homework Statement
i am perplexed with eqn 2.54 peskins introductory qft. just can't make out how to arrive at it from the previous step. i think that there are dirac delta funtions involved but simply can't make it out. can somebody help? provide some hint? thanks...
Homework Statement
Hi
I was trying to get the expression for H ,eqn 2.31 on page 21 peskins introductory QFT
Homework Equations
I get the final expression only if a^+_{-p}\ a_{-p} = a^+_{p}\ a_{p}
so pls tell me if a^+_{-p}\ a_{-p} = a^+_{p}\ a_{p}
(+ stands for dagger) thanks in advance