[ALPS-users] current correlation function for fermionic hubbard model using alps

I am using alps for the calculation of charge correlation function for the fermionic hubbard model. Now I want to calculate the current correlation function. the expression for the charge correlation function is < n_i : n_j > = < c_i^+ c_i : c_j^+ c_j > the expression for the current correlation function is < j_i : j_j > = < c_i^+ c_j : c_k^+ c_l > Notice the changing indices in the current expression. If it is possible then please give the program statements doing this Best Regards Khalid Loane