sparsediag on lattice with different edge types - Comp-phys-alps-users

24 Mar 2015


      Hi all,
I'm trying to do exact diagonalization (with sparsediag) for a spin tube 
(see lattice description below). Everything goes fine, but energy I get 
is about twice higher (by absolute value) than expected (I can treat 
small lattices with other means). This looks suspiciously similar to 
[1], but that message was left unanswered for two years.
Am I doing anything wrong or is this a bug in sparsediag? For the 
latter, I can help with debugging. Thank you in advance!
1. 
https://lists.phys.ethz.ch/pipermail/comp-phys-alps-users/2013/002100.html
Params file:
LATTICE_LIBRARY="./my_lattice.xml"
LATTICE="ladder"
W=4
MODEL="spin";
CONSERVED_QUANTUMNUMBERS="Sz";
TRANSLAION_SYMMETRY=false;
local_S=1/2;
J1=1.0;
J2=-0.0625;
J3=-0.125;
Sz_total=0
{L=6}
Sz_total=1
{L=6}
Lattice description is as follows:
<LATTICES>
<LATTICE name="square lattice" dimension="2">
   <PARAMETER name="a" default="1"/>
   <BASIS><VECTOR>a 0</VECTOR><VECTOR>0 a</VECTOR></BASIS>
</LATTICE>
<FINITELATTICE name="rectangular half-open" dimension="2">
   <LATTICE ref="square lattice"/>
   <EXTENT dimension="1" size="L"/>
   <EXTENT dimension="2" size="W"/>
   <BOUNDARY dimension="1" type="open"/>
   <BOUNDARY dimension="2" type="periodic"/>
</FINITELATTICE>
<UNITCELL name="nnn" dimension="2">
   <VERTEX/>
   <EDGE type="1">
     <SOURCE vertex="1"/>
     <TARGET vertex="1" offset="1 0"/>
   </EDGE>
   <EDGE type="2">
     <SOURCE vertex="1"/>
     <TARGET vertex="1" offset="0 2"/>
   </EDGE>
   <EDGE type="3">
     <SOURCE vertex="1"/>
     <TARGET vertex="1" offset="0 1"/>
   </EDGE>
</UNITCELL>
<LATTICEGRAPH name="ladder">
   <FINITELATTICE ref="rectangular half-open"/>
   <UNITCELL ref="nnn"/>
</LATTICEGRAPH>
</LATTICES>
--
Regards,
Valentine Sinitsyn