- #1
CAF123
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As part of a physics calculation, I have the following integral $$\int d \bar x a^{\sigma} \left[-\partial_{\mu}\left(\frac{\delta x^{\nu}}{\delta a^{\sigma}}\right) (\partial_{\nu}\Phi )\frac{\partial L}{\partial (\partial_{\mu}\Phi)} + \partial_{\mu}\left(\frac{\delta x^{\mu}}{\delta a^{\sigma}}\right)L\right],$$ with Einstein summation convention understood.
Using the fact that ##x'^{\mu} = x^{\mu} + a^{\mu}\,\,\,(1)##, this reduces to
$$\int d \bar x a^{\sigma} \left[-\partial_{\mu}\delta^{\nu}_{\sigma} (\partial_{\nu} \Phi) \frac{\partial L}{\partial (\partial_{\mu}\Phi)} + \partial_{\mu} \delta^{\mu}_{\sigma}L\right]$$
In the first term in the first integral the term ##\partial_{\mu}## only acts on the bracketed term shown. When I use the result (1) this bracketed term changes to a delta, which then consequently changes the index on the following ##\partial_{\nu}## term. My question is, what does the term ##\partial_{\mu}## now act on? Before it acted only on the bracketed term, but now that that is replaced with a delta and using the fact that ##\delta^{\nu}_{\sigma}\partial_{\nu} = \partial_{\sigma}## it seems that the only possibility would be for it to act on the new ##\partial_{\sigma}\Phi## term. Is that correct?
Using the fact that ##x'^{\mu} = x^{\mu} + a^{\mu}\,\,\,(1)##, this reduces to
$$\int d \bar x a^{\sigma} \left[-\partial_{\mu}\delta^{\nu}_{\sigma} (\partial_{\nu} \Phi) \frac{\partial L}{\partial (\partial_{\mu}\Phi)} + \partial_{\mu} \delta^{\mu}_{\sigma}L\right]$$
In the first term in the first integral the term ##\partial_{\mu}## only acts on the bracketed term shown. When I use the result (1) this bracketed term changes to a delta, which then consequently changes the index on the following ##\partial_{\nu}## term. My question is, what does the term ##\partial_{\mu}## now act on? Before it acted only on the bracketed term, but now that that is replaced with a delta and using the fact that ##\delta^{\nu}_{\sigma}\partial_{\nu} = \partial_{\sigma}## it seems that the only possibility would be for it to act on the new ##\partial_{\sigma}\Phi## term. Is that correct?