Hello, I need to create my own Hamiltonian. I have a term of nearest-neighbor interaction, and I write in the model file </BONDTERM> <BONDTERM source="i" target="j"> -t*bdag(i)*b(j) </BONDTERM> Here in the field of the target should I write target="i+1" or should I write simply target="j". What is the difference between the two cases ? In the second case, the source i will go through all the sites and the target j will go through alll the sites too, I have then interaction of next-nearest-neighbor terms and so on ? Thank you for your reply. Best wishes Tianyou