# Normal ordering in an interacting field theory

1. Dec 5, 2014

### SheikYerbouti

I am using Mandl and Shaw and Lahiri to get an introduction to QFT. Something I haven't seen discussed much or at all is whether the commutators or anti-commutators vanish for the normal ordering of a product of different field operators. As a concrete example, let's say that I want to normal order $\bar \psi^- \psi^+ \phi^-$, where $\psi$ is fermionic and $\phi$ is bosonic. Does the term pick up a minus sign or not and why?

2. Dec 10, 2014

### Greg Bernhardt

Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?