LAHLH
- 405
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Hi,
I'm having a little troubling reaching this equation. I'm starting with 2.14 which is:
U(\Lambda)^{-1} M^{\mu\nu} U(\Lambda)=\Lambda^\mu{}_{\rho}\Lambda^\nu{}_{\sigma} M^{\rho\sigma}
Now letting \Lambda=1+\delta\omega and using U(1+\delta\omega)=I+\frac{i}{2\hbar} \delta\omega_{\mu\nu}M^{\mu\nu}, I get:
U(1+\delta\omega )^{-1} M^{\mu\nu} U(1+\delta\omega)=\Lambda^\mu{}_{\rho}\Lambda^\nu{}_{\sigma} M^{\rho\sigma}
=> (I-\frac{i}{2\hbar} \delta\omega_{\alpha\beta}M^{\alpha\beta}) M^{\mu\nu}( I+\frac{i}{2\hbar} \delta\omega_{\xi\chi}M^{\xi\chi})=\Lambda^\mu{}_{\rho}\Lambda^\nu{}_{\sigma} M^{\rho\sigma}
=> M^{\mu\nu}+\frac{i}{2\hbar} \delta\omega_{\xi\chi}M^{\mu\nu}M^{\xi\chi}-\frac{i}{2\hbar} \delta\omega_{\alpha\beta}M^{\alpha\beta}M^{\mu\nu}=\Lambda^\mu{}_{\rho}\Lambda^\nu{}_{\sigma} M^{\rho\sigma}
I'm not really sure where to go from here, I guess I can't simply say \Lambda^\mu{}_{\rho}\Lambda^\nu{}_{\sigma} M^{\rho\sigma}=M^{\mu\nu} and cancel this from each side?
Not sure how else I could get some that had \delta\omega in every term otherwise, so I can equate the antisymmetric parts of there coefficients as Srednicki suggests.
Thanks for any help
I'm having a little troubling reaching this equation. I'm starting with 2.14 which is:
U(\Lambda)^{-1} M^{\mu\nu} U(\Lambda)=\Lambda^\mu{}_{\rho}\Lambda^\nu{}_{\sigma} M^{\rho\sigma}
Now letting \Lambda=1+\delta\omega and using U(1+\delta\omega)=I+\frac{i}{2\hbar} \delta\omega_{\mu\nu}M^{\mu\nu}, I get:
U(1+\delta\omega )^{-1} M^{\mu\nu} U(1+\delta\omega)=\Lambda^\mu{}_{\rho}\Lambda^\nu{}_{\sigma} M^{\rho\sigma}
=> (I-\frac{i}{2\hbar} \delta\omega_{\alpha\beta}M^{\alpha\beta}) M^{\mu\nu}( I+\frac{i}{2\hbar} \delta\omega_{\xi\chi}M^{\xi\chi})=\Lambda^\mu{}_{\rho}\Lambda^\nu{}_{\sigma} M^{\rho\sigma}
=> M^{\mu\nu}+\frac{i}{2\hbar} \delta\omega_{\xi\chi}M^{\mu\nu}M^{\xi\chi}-\frac{i}{2\hbar} \delta\omega_{\alpha\beta}M^{\alpha\beta}M^{\mu\nu}=\Lambda^\mu{}_{\rho}\Lambda^\nu{}_{\sigma} M^{\rho\sigma}
I'm not really sure where to go from here, I guess I can't simply say \Lambda^\mu{}_{\rho}\Lambda^\nu{}_{\sigma} M^{\rho\sigma}=M^{\mu\nu} and cancel this from each side?
Not sure how else I could get some that had \delta\omega in every term otherwise, so I can equate the antisymmetric parts of there coefficients as Srednicki suggests.
Thanks for any help