Dear Matthias, Thank you for your reply. I have one more question about DMRG. I try to calculate a gap of xxz spin model (Jz != Jxy) for different values of Jz and Jxy. I think that it will be more safe to assume that I do not know in what Sz sector search for a ground and excited states. Is it in this case better option to run simulation over all possible Sz by hand or to comment a line #'Sz_total' : Sz. which should force alps to work in the grand canonical as it was told in the first tutorial on the webpage? I tried this second approach for the ising model (Jxy = 0, Jz = 1) but what I get was just a duplicated ground state without a correct excited state. Bests, Rafał 2013/11/18 Matthias Troyer <troyer@phys.ethz.ch>
Yes, you can drop it if N does not exist
On Nov 18, 2013, at 21:33, Rafał <arymanus@gmail.com> wrote:
Dear all ALPS users,
I have following questions to the DMRG tutorials. Why there is N in a line: 'CONSERVED_QUANTUMNUMBERS' : 'N,Sz',
I understand that Sz stands for conserved quantum number but spin model on the open chain lattice does not have quantum number called N.
Is this N added to 'CONSERVED_QUANTUMNUMBERS' just in case someone may use some bosonic model?
Bests, Rafał