Electromagnetic Lagrangian, EoM, Polarisation States

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SUMMARY

The discussion centers on the application of the Euler-Lagrange equations to derive the equations of motion (EoM) for electromagnetic fields, specifically focusing on the properties of the antisymmetric tensor \( F_{\mu \nu} \). Participants clarify that for an antisymmetric tensor, all diagonal entries, including \( F_{00} \) and \( F_{ii} \), must equal zero. This conclusion is supported by equation (9) in the attached solution, which explicitly demonstrates the antisymmetry of \( F_{\mu \nu} \).

PREREQUISITES
  • Understanding of the Euler-Lagrange equations
  • Familiarity with antisymmetric tensors
  • Basic knowledge of electromagnetic field theory
  • Ability to interpret mathematical equations in physics
NEXT STEPS
  • Study the derivation of the Euler-Lagrange equations in classical mechanics
  • Learn about the properties of antisymmetric tensors in physics
  • Explore the implications of electromagnetic field equations in theoretical physics
  • Investigate the role of polarization states in electromagnetic theory
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Students of physics, particularly those studying electromagnetism, theoretical physicists, and anyone interested in the mathematical foundations of field theory.

binbagsss
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Homework Statement



Attached:

queey.png

Homework Equations



Euler-Lagrange equations to find the EoM

The Attempt at a Solution


[/B]
Solution attached:

solly.png


I follow, up to where the sum over ##\mu## reduces to sum over ##\mu=i## only, why are there no ##\mu=0## terms? I don't understand at all.

Many thanks
 

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According to equation (9), what can you say about ##F_{00}##? What does this tell you about ##F^{00}##?
 
TSny said:
According to equation (9), what can you say about ##F_{00}##? What does this tell you about ##F^{00}##?

oh for a antisymmetric tensor all diagonal entries must be zero? ##F_{ii}=0 ## as is ##F_{00} ##?
 
binbagsss said:
oh for a antisymmetric tensor all diagonal entries must be zero? ##F_{ii}=0 ## as is ##F_{00} ##?
Yes. The expression for ##F_{\mu \nu}## in (9) shows that ##F## is antisymmetric. In particular, if you let ##\mu = 0## and ##\nu = 0## in the expression for ##F_{\mu \nu}## in (9) then you see that ##F_{00} = 0##.
 

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