Hi, a small question about the LSZ reduction formula, as treated in Srednicki's QFT book (chapter 5).(adsbygoogle = window.adsbygoogle || []).push({});

He argues that in a QFT in a scalar theory with interactions you would like that

[tex]

<0|\phi(x)|0> = <0|\phi(0)|0> = 0

[/tex]

and

[tex]

<p|\phi(0)|0> = 1

[/tex]

For the first he argues that were this NOT the case, then the creation operators [itex] a^\dagger (\pm\infty)[/itex] would create a linear combination of a single particle state and the ground state.

For the second he argues that the second condition accounts for the fact that the creation operators create a correctly normalized one-particle state.

How does one see these two statements? Thanks in forward! :)

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# The LSZ reduction formula

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