Hi Jun,
This is not currently implemented but depending on which code you use it can be added.
Matthias
On 25 Jun 2010, at 09:59, Jun Wen wrote:
> Hello all,
>
> I have been trying to compute the expectation value of
> cdag(1) c(2) cdag(3) c(4) where two creation and two destruction operators are involved and 1, 2 ,3 and 4 label the sites in a spinless Hubbard model. Could anyone kindly tell me how I should define this in the parameter file or in the models.xml?
> Thanks a lot!
>
> Best,
>
> Jun