Dear all,

  I use dirloop_sse to calculate the hardcore-boson Hubbard model, but with next nearest neighbor hoppings. I revised the model and lattice as below or in the attached file. However the result is not correct. I want to know where the problem is. Thank you very much.

Sincerely,

Huaiming Guo

<HAMILTONIAN name="hardcore boson">

  <PARAMETER name="mu" default="0"/>

  <PARAMETER name="t" default="1"/>

  <PARAMETER name="V" default="0"/>

  <PARAMETER name="t'" default="0"/>

  <PARAMETER name="V'" default="0"/>

  <PARAMETER name="t''" default="0"/>

  <PARAMETER name="V''" default="0"/>

  <PARAMETER name="t0" default="t"/>

  <PARAMETER name="t1" default="t'"/>

  <PARAMETER name="V0" default="V"/>

  <PARAMETER name="V1" default="V'"/>

  <BASIS ref="hardcore boson"/>

  <SITETERM site="i">

    <PARAMETER name="mu#" default="mu"/>

    -mu#*n(i)

  </SITETERM>

  <BONDTERM source="i" target="j">

    <PARAMETER name="t#" default="0"/>

    <PARAMETER name="V#" default="0"/>

    -t#*(bdag(i)*b(j)+bdag(j)*b(i)) + V#*n(i)*n(j)

  </BONDTERM>

</HAMILTONIAN>

<UNITCELL name="nnn2d" dimension="2">

  <VERTEX/>

  <EDGE type="0"><SOURCE vertex="1" offset="0 0"/><TARGET vertex="1" offset="0 1"/></EDGE>

  <EDGE type="1"><SOURCE vertex="1" offset="0 0"/><TARGET vertex="1" offset="1 0"/></EDGE>

  <EDGE type="2"><SOURCE vertex="1" offset="0 0"/><TARGET vertex="1" offset="1 1"/></EDGE>

  <EDGE type="2"><SOURCE vertex="1" offset="0 0"/><TARGET vertex="1" offset="1 -1"/></EDGE>

</UNITCELL>

<LATTICEGRAPH name = "ladder" vt_name="LadderLattice">

  <FINITELATTICE>

    <LATTICE ref="square lattice"/>

    <PARAMETER name="W" default="2"/>

    <EXTENT dimension="1" size="L"/>

    <EXTENT dimension="2" size="W"/>

    <BOUNDARY dimension="1" type="periodic"/>

    <BOUNDARY dimension="2" type="open"/>

  </FINITELATTICE>

  <UNITCELL ref="nnn2d"/>

</LATTICEGRAPH>