Dear all<div><br></div><div>   I test a Hubbard model with external potential (double well) using DMRG code in ALPS, </div><div>   but I can not get a symmetry result (density distribution) with SWEEP and MAXSTATES up to 50 and 500, respectively. </div>

<div>   It seem that I need to set more SWEEPS and STATES in calculation. But it cast to much time and is not very practical.</div><div>   </div><div>   I found that the symmetry between spin-up and spin-down atoms is not kept in my present result, i.e. </div>

<div>   the density distributions of the two kinds of atoms are different ( I have set Sz as &quot;CONSERVED_QUANTUMNUMBERS&quot; </div><div>   and Sz_total=0 in command file). </div><div><br></div><div>   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 ?</div>

<div>   or  may be I should use a better series of STATES ?</div><div><br></div><div>   Any comments are welcome.</div><div>   thank you.</div><div><br></div><div>chenahai</div><div><br></div><div><br></div><div><div><br>

</div>-- <br>--------------------------------------------------------------------------<br>Chen Ahai<br>Department of Physics, Zhejiang Normal University<br>Jinhua, Zhejiang Province, 321004, China<br>
e-mail: <a href="mailto:chenahaiphysics@gmail.com" target="_blank">chenahaiphysics@gmail.com</a>;<br>           <a href="mailto:chenahai@yahoo.cn" target="_blank">chenahai@yahoo.cn</a><br><br><br>
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