Lagrangian of the EM field -- question

  • I
  • Thread starter -marko-
  • Start date
  • #1
9
0

Main Question or Discussion Point

The EM Lagrangian is
$$\mathcal{L} = -\frac{1}{2}[(\partial_\mu A_\nu)(\partial^\mu A^\nu) - (\partial_\mu A_\nu)(\partial^\nu A^\mu)]$$

In the QFT notes from Tong the EM Lagrangian is written in the form
$$\mathcal{L} = -\frac{1}{2}[(\partial_\mu A_\nu)(\partial^\mu A^\nu) - (\partial_\mu A^\mu)^2]$$

I don't see how did he get ##(\partial_\mu A^\mu)^2## term? Thanks :)
 

Answers and Replies

  • #2
Orodruin
Staff Emeritus
Science Advisor
Homework Helper
Insights Author
Gold Member
16,585
6,345
Integration by parts. What is relevant is not the Lagrangian density, but the action.
 
  • #3
9
0
Integration by parts. What is relevant is not the Lagrangian density, but the action.
Many thanks, it's clear now.
 

Related Threads for: Lagrangian of the EM field -- question

  • Last Post
Replies
2
Views
706
Replies
4
Views
2K
Replies
2
Views
568
Replies
15
Views
2K
  • Last Post
Replies
2
Views
2K
Replies
4
Views
1K
  • Last Post
Replies
8
Views
3K
Replies
7
Views
583
Top