As I understand it, the time ordering operator works as follows (for [tex]t<0[/tex]):(adsbygoogle = window.adsbygoogle || []).push({});

[tex]T c^\dagger(t) c(0) = -c(0) c^\dagger(t)[/tex] for fermions and

[tex]T c^\dagger(t) c(0) = c(0) c^\dagger(t)[/tex] for bosons.

Now suppose instead of these creation/annihilation operators, I had a more general commutation relation, ie [tex][d,d^\dagger] = S[/tex], how does the time ordering operator behave?

Edit: After rereading that, I should be more specific. I'm trying to formulate DMFT equations in a non-orthogonal basis. So the creation/annihilation operators anti-commute to give [d_a,d_b^\dagger]_+ = S_{a,b}. The Green's function is usually defined as [tex]G(\tau) = \langle T c(\tau) c^\dagger(0) \rangle[/tex] and I need to understand exactly what the time ordering operator does, but I'm not even totally sure how its really defined, because as I understand it above, it works differently for fermions and bosons.

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# Time ordering operator

Can you offer guidance or do you also need help?

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