I am very new of tensor network techniques and I have three very naive questions. I would like to measure the ground state entaglement entropy of an interval A that extends between the sites m and m+l of an XXZ chain and the rest fo the chain. I am interested in three cases:
1) The full chain has periodic boundary conditions
2)The full chain has open boundary conditions.
3)The full chain is infinite
How this can be done?
Thanks a lot!