Help with Equation 9.25 in Srednicki's QFT Book?

  • Context: Graduate 
  • Thread starter Thread starter kexue
  • Start date Start date
  • Tags Tags
    Book Qft
Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
3 replies · 3K views
kexue
Messages
195
Reaction score
2
Can anybody help me out with equation 9.25 in Srednicki's QFT book?

He says the in the eq. 9.25 an integration by parts has been carried out. I do not see how. I guess we integrate 9.9 and get then 9.25 somehow, but how? Any hints?

thank you
 
Physics news on Phys.org
Yes, starting with 9.9,
[tex]-{1\over2}\int d^4x(A\partial^\mu\varphi\partial_\mu\varphi+Bm^2\varphi^2)[/tex]
we partially integrate to move [itex]\partial^\mu[/itex] from the first [itex]\varphi[/itex] to the second, which results in
[tex]-{1\over2}\int d^4x(-A\varphi\partial^\mu\partial_\mu\varphi+Bm^2\varphi^2)[/tex]
Then we replace fields by functional derivatives in the way that's done throughout section 9.
 
Thanks so much, Avodyne! You are the Srednicki guy, who never let's us down. I rather randomly pick up the book when I'm in the mood to learn some QFT. Well, and as it is, I always quickly stumble upon some equations I don't understand. So thanks so much for the help, because I really want to learn QFT, no matter what!