Comp-phys-alps-users

comp-phys-alps-users@lists.phys.ethz.ch

February 2019

1 participants
2 discussions

Question about Kondo lattice model 2
by riku.masui＠yukawa.kyoto-u.ac.jp 28 Feb '19

28 Feb '19

Dear ALPS users and developers, I solved the problem which I sent to this mailing list on February 1st by myself, but I got another problem about Kondo lattice model. I am studying one dimensional Kondo lattice model with ALPS DMRG application, and in a small system(L=4),I compared the ground state energy which I got by ALPS DMRG with the one which I got by exact diagoanlization in the case t=0,J=1 and I fixed the number of conduction electrons 4(i.e. half-filled).Then I got E0=-1.6160254... by DMRG and E0 =-3.00000...by exact diagonalization. The latter seems to be reasonable, but I don't have any idea about where DMRG is wrong. I used ALPS lattice library and "2 band open chain lattice", and the model library to which I added a quantum number "N" and a constraint in order to fix the number of conduction electrons. I have attached the model library xml file to this email. And I used the following parameter file: 'LATTICE' : "2 band open chain lattice", 'MODEL_LIBRARY' :"kondo_lattice_ model.xml", 'MODEL' : "Kondo lattice ", 'CONSERVED_QUANTUMNUMBERS' :"N", 'N_total' :4, 'local_spin' :0.5, 't' :0, 'J' :1, 'SWEEPS' : 6, 'NUMBER_EIGENVALUES' : 2, 'L' : 4, 'MAXSTATES' : 150 Any advice will help me. Best regards, Riku Masui

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Question about Kondo lattice model
by riku.masui＠yukawa.kyoto-u.ac.jp 01 Feb '19

01 Feb '19

Dear ALPS users and developers, I am a beginner of ALPS and English writing. I am studying Kondo lattice model with alps dmrg application for python. I tried to calculate correlation functions <S(i)S(j)> between local spins using 'Kondo lattice' model and '2 band open chain lattice' ,which are in alps lib and I didn't change anything. And I used the following parameter file: parms = [ { 'LATTICE' : '2 band open chain lattice', 'MODEL' : 'Kondo lattice', 'local_S' :0.5, 't' : 1, 'J' : 1, 'SWEEPS' : 4, 'NUMBER_EIGENVALUES' : 1, 'L' : 32, 'MAXSTATES' : 300, 'MEASURE_CORRELATIONS[Momentumup]' :'cdag_up:c_up', 'MEASURE_CORRELATIONS[Momentumdown]' :'cdag_down:c_down', 'MEASURE_AVERAGE[Magnetization]' : 'Sz', 'MEASURE_AVERAGE[Exchange]' : 'exchange', 'MEASURE_LOCAL[Local magnetization]' : 'Sz', 'MEASURE_CORRELATIONS[Diagonal spin correlations]' : 'Sz', 'MEASURE_CORRELATIONS[Offdiagonal spin correlations]' : 'Splus: Sminus' } ] However, dmrg doesn't run and returned the error "Cannot evaluate expression c_down(j)". This might be a foolish question, but I have no idea. So, could you give me some advice? Any advice will help me. Best regards, Riku Masui

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