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abode_x
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Homework Statement
I am trying to learn from Srednicki's QFT book. I am in chapter 2 stuck in problem 2 and 3. This is mainly because I don't know what the unitary operator does - what the details are.
Starting from:
[tex]U(\Lambda)^{-1}U(\Lambda')U(\Lambda)=U(\Lambda^{-1}\Lambda'\Lambda)[/tex]
How does one arrive at:
[tex]\delta\omega_{\mu\nu}U(\Lambda)^{-1}M^{\mu\nu}U(\Lambda)=\delta\omega_{\mu\nu}\Lambda^{\mu}_{\rho}\Lambda^{\nu}_{\sigma}M^{\mu\nu}[/tex]
Homework Equations
Given that:
[tex]\Lambda '=1+\delta\omega [/tex]
[tex]U(1+\delta\omega)=I + \frac{i}{2 \hbar}\delta\omega_{\mu\nu}M^{\mu\nu}[/tex]
The Attempt at a Solution
Working out the left hand side from the given, I end up with
[tex]I+\frac{i}{2 \hbar}\delta\omega_{\mu\nu}U(\Lambda)^{-1}M^{\mu\nu}U(\Lambda)[/tex]
As for the RHS, I don't know the details. Why do I end up with those contractions of two Lorentz transformations with the generator of the Lorentz group M?
Also, since I'm already here, I would also like to ask what is meant by,
[tex][M^{\mu\nu},M^{\rho\sigma}]=i\hbar (g^{\mu\rho}M^{\mu\nu} - (\mu \leftrightarrow \nu) ) - ( \rho \leftrightarrow \sigma ) [/tex]
specifically the notation with the double arrow. It seems like an index replacement?
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