[ALPS-users] Lowest spectrum of the hubbard model on a plaquette

Dear alps team,

I am reproducing the spectrum on page 3 of this paper, which is the Lowest spectrum of the hubbard model on a plaquette. Eigenstates are labelled by total spin S and plaquette momentum Qx,Qy = 0, π.

author = "Ehud Altman and Assa Auerbach", title = "Plaquette Boson -- Fermion Model of Cuprates", condmat = "cond-mat/0108087",

I have written the following program

LATTICE_LIBRARY="/temp/ALPS/xml/lattices.xml" MODEL_LIBRARY="/temp/ALPS/xml/models.xml"

MODEL="fermion Hubbard" LATTICE="anisotropic square lattice"

L=2 W=2 U=1000000000

CONSERVED_QUANTUMNUMBERS="N,Sz"

{N_total=3; Sz_total=0.5; t=1.0;} {N_total=3; Sz_total=1.5; t=1.0;}

my results with fulldiag are not matching with the paper. Probably I am not mentiong the total_spin total_particle or conserved quantum number properly.

i recognize 0 holes as 4 particles, 1 holes as 3 particles and 2 holes as 2 particles in 2 by 2 pluquette.

Please take some time to correct me.

Best Regards Khalid loane