Dear all
I test a Hubbard model with external potential (double well) using DMRG code in ALPS, but I can not get a symmetry result (density distribution) with SWEEP and MAXSTATES up to 50 and 500, respectively. It seem that I need to set more SWEEPS and STATES in calculation. But it cast to much time and is not very practical.
I found that the symmetry between spin-up and spin-down atoms is not kept in my present result, i.e. the density distributions of the two kinds of atoms are different ( I have set Sz as "CONSERVED_QUANTUMNUMBERS" and Sz_total=0 in command file).
I wonder if there are some ways for me to restrict the Sz in each site to 0 and obtain the correct result with a few SWEEPS ? or may be I should use a better series of STATES ?
Any comments are welcome. thank you.
chenahai