Dear ALPS team, I have successfully performed a full diagonalization for a Hubbard chain with periodic boundary conditions using the included models in xml files. Now, I'd like to perform the same task with antiperiodic boundary conditions (a fermionic hopping with opposite sign) at chain ends, or more generally with exponetial complex phase, possibly by using again the xml input schema. Can you give me some hint ? Is it also possible to specify the hamiltonian or any other operator in a more extended form, with the site indices explicitly defined in the expression, as one would do with Mathematica, such as for instance -t#*fermion_hop(1,2) + t#*fermion_hop(3,4) + ... and so on ?

Thank you for your support Best regards

Jessica Alfonsi