Covariant derivatives commutator - field strength tensor

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SUMMARY

The discussion focuses on deriving the field strength tensor using the covariant derivatives commutator, specifically the expression [D_{\mu},D_{\nu}] = (\partial_{\mu} + A_{\mu})(\partial_{\nu} + A_{\nu}) - (\mu <-> \nu). The key conclusion is that the terms [\partial_{\mu},\partial_{\nu}] cancel out, leaving the expression as \partial_{\mu}A_{\nu} - \partial_{\nu}A_{\mu} + [A_{\mu},A_{\nu}]. The remaining terms involve the derivatives acting on the gauge fields A_{\mu} and A_{\nu}, confirming the non-commutativity of the covariant derivatives in gauge theory.

PREREQUISITES
  • Understanding of covariant derivatives in differential geometry
  • Familiarity with gauge theory and field strength tensors
  • Knowledge of the properties of Lie brackets in the context of vector fields
  • Proficiency in tensor calculus and partial derivatives
NEXT STEPS
  • Study the derivation of the field strength tensor in Yang-Mills theory
  • Explore the implications of non-commuting covariant derivatives in gauge theories
  • Learn about the role of the Lie algebra in the context of gauge fields
  • Investigate the physical significance of the field strength tensor in electromagnetism and other gauge theories
USEFUL FOR

This discussion is beneficial for theoretical physicists, graduate students in physics, and researchers focusing on gauge theories and differential geometry.

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Homework Statement


So I've been trying to derive field strength tensor. What to do with the last 2 parts ? They obviously don't cancel (or do they?)

Homework Equations

The Attempt at a Solution


[D_{\mu},D_{\nu}] = (\partial_{\mu} + A_{\mu})(\partial_{\nu} + A_{\nu}) - (\mu &lt;-&gt; \nu) = [\partial_{\mu},\partial_{\nu}] + [\partial_{\mu},A_{\nu}]+[A_{\mu},\partial_{\nu}] +[A_{\mu}, A_{\nu}] =
\partial_{\mu}A_{\nu} - \partial_{\nu} A_{\mu} + [A_{\mu},A_{\nu}] -A_{\nu} \partial_{\mu} + A_{\mu} \partial_{\nu}
 
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They are canceled by the first two terms when the derivative acts on whatever function the entire operator is acting on. What remains is just the derivative acting on the A fields.
 
Thank you
 

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