Longitudinal polarization in Feynman photon propagator?

  • #1
For internal photon states, is it necessary to sum over the longitudinal polarization state in addition to the transverse states? And if so, does the ordinary Feynman-gauge propagator take care of this?

Thanks!
 

Answers and Replies

  • #2
Avodyne
Science Advisor
1,396
88
No. However, the longitudinal states do not couple to the conserved electromagnetic current, so it doesn't matter whether you include them or not. Thus the ##k^\mu k^\nu## term in the propagator can be multiplied by an arbitrary number (this is sometimes called "generalized Feynman gauge"), and the scattering amplitudes do not depend on that number.
 
  • Like
Likes vanhees71

Related Threads on Longitudinal polarization in Feynman photon propagator?

  • Last Post
Replies
4
Views
2K
  • Last Post
Replies
0
Views
1K
  • Last Post
Replies
11
Views
9K
  • Last Post
Replies
13
Views
1K
  • Last Post
2
Replies
35
Views
3K
Replies
0
Views
950
  • Last Post
Replies
0
Views
2K
Replies
2
Views
985
Replies
7
Views
2K
Replies
5
Views
8K
Top