Obtaining field equations from an action

Click For Summary
SUMMARY

The discussion centers on deriving field equations from a given action using the Euler-Lagrange method. The action provided is S[A_\nu] = ∫[(1/4)(A_{\gamma,\mu}-A_{\mu,\gamma})(A_{\zeta,\alpha}-A_{\alpha,\zeta})η^{\gamma\zeta}η^{\mu\alpha} + (1/2)ν²A_μA_γ - βA_μJ^μ]√(-η) d⁴x. Participants emphasize the importance of recognizing the terms as F_{\mu\nu}F^{\mu\nu} and express a need for resources that clarify the application of the Euler-Lagrange method in 4-vector notation.

PREREQUISITES
  • Understanding of the Euler-Lagrange equation
  • Familiarity with 4-vector notation in physics
  • Knowledge of field theory concepts
  • Basic grasp of tensor calculus
NEXT STEPS
  • Study the derivation of field equations using the Euler-Lagrange method
  • Explore resources on 4-vector notation and its applications in field theory
  • Learn about the significance of the electromagnetic field tensor F_{\mu\nu}
  • Review advanced textbooks on classical field theory for detailed methodologies
USEFUL FOR

Students of theoretical physics, researchers in field theory, and anyone seeking to deepen their understanding of deriving field equations from actions using the Euler-Lagrange method.

hepnoob92
Messages
1
Reaction score
0

Homework Statement


Provided an action:
S[A_\nu] = \int\left(\frac{1}{4}(A_{\gamma,\mu}-A_{\mu,\gamma})(A_{\zeta,\alpha}-A_{\alpha,\zeta})\eta^{\gamma\zeta}\eta^{\mu\alpha}+\frac{1}{2}\nu^2A_\mu A_\gamma -\beta A_\mu J^\mu\right)\sqrt{-\eta}~d^4x

How would one go about finding the field equations for the same? I do understand that using the Euler-Lagrange method is how one should start out.

Does it tell us what kind of field we're looking at, at a glance?

Homework Equations


The Attempt at a Solution



I know that the terms in the parentheses are just ##F_{\mu\nu}F^{\mu\nu}##, but am unsure of how to proceed.

Additionally:
Does anyone know any good resources online or books that derive field equations and extract physics from a given action in steps, giving a good detailed process from which one can observe and learn how the Euler Lagrange method is being applied, in terms of the 4-vector notation. My struggle is essentially in decoding the physics, largely due to problems with understanding the notation.
 
Last edited:
Physics news on Phys.org
hepnoob92 said:
I do understand that using the Euler-Lagrange method is how one should start out.
Right, so what do you get when you do the EL equation for a single component ##A_\lambda## of the field?
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 18 ·
Replies
18
Views
3K
Replies
10
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
8
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K