- #1
PhysiSmo
We have the Lagrangian of EM field: [tex]L=-\frac{1}{4}F_{\mu\nu}F^{\mu\nu}[/tex]
Variation of Lagrangian give Maxwell's equations:
[tex]\partial_{\mu} F^{\mu\nu}=0[/tex].
or
[tex](g_{\mu\nu}\partial_{\mu}\partial^{\mu}-\partial_{\mu}\partial_{\nu})A^{\mu}=0.[/tex] (equation 7.3, p.241)
Ryder, then, claims that after partial integration, and discarding of surface terms, Lagrangian may be written
[tex]L=\frac{1}{2}A^{\mu}[g_{\mu\nu}\partial_{\mu}\partial^{\mu}-\partial_{\mu}\partial_{\nu}]A^{\nu}[/tex].
I simply can't figure out this last derivation. Which quantity has to be integrated to give such result? How do we obtain this particular form? I played with various quantities and integrals, but can't prove it..thanx in advance.
Variation of Lagrangian give Maxwell's equations:
[tex]\partial_{\mu} F^{\mu\nu}=0[/tex].
or
[tex](g_{\mu\nu}\partial_{\mu}\partial^{\mu}-\partial_{\mu}\partial_{\nu})A^{\mu}=0.[/tex] (equation 7.3, p.241)
Ryder, then, claims that after partial integration, and discarding of surface terms, Lagrangian may be written
[tex]L=\frac{1}{2}A^{\mu}[g_{\mu\nu}\partial_{\mu}\partial^{\mu}-\partial_{\mu}\partial_{\nu}]A^{\nu}[/tex].
I simply can't figure out this last derivation. Which quantity has to be integrated to give such result? How do we obtain this particular form? I played with various quantities and integrals, but can't prove it..thanx in advance.