Dear ALPS users,
I am trying to simulate two-leg ladders models of say hardcore bosons. I need that the lower and upper leg have different chemical potentials, mu0 and mu1 respectively. How can I implement that efficiently ?
My naive idea:
1. define a unit cell with two vertex (lower and upper site) plus three edges (two horizontal+one vertical):
<UNITCELL name="ladderCell" dimension="1"> <VERTEX type="0"/> <VERTEX type="1"/> <EDGE type="0"> <SOURCE vertex="0" offset="0"/> <TARGET vertex="0" offset="1"/> </EDGE> <EDGE type="1"> <SOURCE vertex="0" offset="0"/> <TARGET vertex="1" offset="0"/> </EDGE> <EDGE type="2"> <SOURCE vertex="1" offset="0"/> <TARGET vertex="1" offset="1"/> </EDGE> </UNITCELL>
2. The two-leg ladder is then a chain of such cells:
<LATTICEGRAPH name = "my open two leg ladder"> <FINITELATTICE> <LATTICE ref="chain lattice"/> <EXTENT dimension="1" size ="L"/> <BOUNDARY type="open"/> </FINITELATTICE> <UNITCELL ref="ladderCell"/> </LATTICEGRAPH>
3. Finally I modify the model hamiltonian including the two different chemical potentials defined as parameters:
<SITETERM type="0" site="i"> -mu0*n(i) </SITETERM> <SITETERM type="1" site="i"> -mu1*n(i) </SITETERM>
When I execute dmrg, the code gets stuck at "parsing task files ..." Could you please help me?
Thank you. My best regards, Giuliano