If n is odd, I understand that the quantity is 0: We can write
the quantity as a sum of monomials in which all
creators are to the right of all annihilators (anti-Wick ordered). A
such monomial is a product of an odd number of factors. Clearly
the vacuum state annihilates a such monomial. We...
We use the antisymmetric Fock space ( "fermions"). We denote by c(h) a creator operator.
I need to evaluate the following quantity:
< \Omega , \big(c(h_1)+c(h_1)^{*}\big)\big(c(h_2)+c(h_2)^{*}\big) \ldots \big(c(h_n)+c(h_n)^*\big)\Omega>
where \Omega is the unit vector called vaccum...