I have posted these messages. They have no answers. Please take some time to answer them as I am student and answers from your part are very important to me. I am waiting

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, ?.

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

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Message: 3 Date: Thu, 16 Apr 2009 11:55:03 -0700 (PDT) From: khalid hassan mkhloane@yahoo.com Subject: [ALPS-users] repharasing the lowest spectrum fermion hubbard question To: alps users alps users comp-phys-alps-users@phys.ethz.ch Message-ID: 178183.68074.qm@web59405.mail.ac4.yahoo.com Content-Type: text/plain; charset=us-ascii

Dear alps team

i want ti rephrase my question to make it more precise

I have

fermion hubbard model 2 by 2 square plaquette total number of particle = 3 total spin S= 1/2

need ground state energy

which will be plaquette momentum (Pi,0) and (0, Pi) degenerate

The program I wrote is giving plaquette momentum (0,0) and (0,Pi) as ground state, which is wrong as seen in the paper.

My statements are under. Please correct my statements. I tried very much but could not find the correct ground states. It is trivial task as written in paper.

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; Sz_total=0.5;

U=0.5;

CONSERVED_QUANTUMNUMBERS="N,Sz" N_total=3

{ t=1.0;}

Best Regards Khalid Loane

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, ?.

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