The problem is showing(adsbygoogle = window.adsbygoogle || []).push({});

(□+m^2)<0| T(∅(x)∅(y)) |0> = -δ^4 (x-y)

I know that it is relavent to Green's function, but the problem is that it should be alternatively solved without any information of Green's function, and using equal time commutation relations.

Does Anyone know that?

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Time ordered product & Green's function

**Physics Forums | Science Articles, Homework Help, Discussion**