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
Click For Summary

Discussion Overview

The discussion revolves around understanding equation 9.25 from Srednicki's Quantum Field Theory (QFT) book, specifically the integration by parts involved in deriving this equation from equation 9.9. Participants seek clarification on the steps taken in the integration process.

Discussion Character

  • Homework-related
  • Technical explanation

Main Points Raised

  • One participant requests help with understanding the integration by parts from equation 9.9 to 9.25.
  • Another participant provides a detailed explanation of the integration process, indicating that they move the derivative from one field to another and replace fields with functional derivatives as per the methods outlined in section 9 of the book.
  • A third participant expresses gratitude for the assistance and shares their motivation to learn QFT despite encountering challenging equations.

Areas of Agreement / Disagreement

Participants generally agree on the steps involved in the integration process, but there is no consensus on the clarity of the explanation or the ease of understanding the material.

Contextual Notes

The discussion does not address potential assumptions or limitations in the integration process or the definitions used in the equations.

Who May Find This Useful

Readers interested in quantum field theory, particularly those studying Srednicki's textbook and seeking clarification on specific equations and integration techniques.

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
Anyone?
 
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!
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
18
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
0
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 14 ·
Replies
14
Views
6K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K