Hello everybody,
I was trying to run a simulation on the one-dimensional superlattice Bose-Hubbarad with alternating tunneling rates t1 and t2, which is the bosonic analogue of the Su-Schrieffer-Heeger(SSH) model. The lattice with one unit cell is made of A and B sites. To this end, I have adaped the following unit-cell: <UNITCELL name="sublattice1d" dimension="1"> <VERTEX type="0"/> <VERTEX type="1"/> <EDGE type="0"><SOURCE vertex="1" offset="0"/><TARGET vertex="2" offset="0"/></EDGE> <EDGE type="1"><SOURCE vertex="2" offset="0"/><TARGET vertex="1" offset="1"/></EDGE> <EDGE type="0"><SOURCE vertex="1" offset="1"/><TARGET vertex="2" offset="1"/></EDGE> </UNITCELL>
This enters into the lattice graph: <LATTICEGRAPH name = "2 band sublattice open chain lattice"> <FINITELATTICE> <LATTICE ref="chain lattice"/> <EXTENT dimension="1" size ="L"/> <BOUNDARY type="open"/> </FINITELATTICE> <UNITCELL ref="sublattice1d"/> </LATTICEGRAPH>
And the Hamiltonian: <HAMILTONIAN name="boson Hubbard"> <PARAMETER name="mu" default="0"/> <PARAMETER name="hop" default="1"/> <PARAMETER name="hop'" default="1"/> <PARAMETER name="U" default="0"/> <BASIS ref="boson"/> <SITETERM site="i"> <PARAMETER name="mu#" default="mu"/> <PARAMETER name="U#" default="U"/> -mu#*n(i)+U#*n(i)*(n(i)-1)/2 </SITETERM> <BONDTERM type="0" source="i" target="j"> -hop*boson_hop(i,j) </BONDTERM> <BONDTERM type="1" source="i" target="j"> -hop'*boson_hop(i,j) </BONDTERM> </HAMILTONIAN>
However when I run a DMRG calculation.I still get the wrong results.I compare the ground state energy of it with which I calculated by matlab using ED method.All the parameters of the two calculation are the same.
I seem to misunderstand the implementation. So the question I want to ask is that are there any wrong in the definitions of my lattice or the model in XML.
Thank you for any kind of heplful remarks.
Yulian Chen