Hi ALPS team,
I am trying to make simple simulations with anisotropic Heisenberg model on a ladder with ALPS2 rc2.
According to models.xml and full diagonalization web page if I specify J0 and J1 parameters then for different bond types "0" and "1" I will have J0 and J1 coefficients in Heisenberg ("spin") model. I did a simple experiment by performing fulldiag two simulations: one by using J=1 and the other J0=1,J1=1 and compared the results.
I expected that the results should be the same according to "spin" model definition: defaults for J0and J1 is J if they are not specified. But I found that the results of energy and other quantities are different. below are my two parameter files:
LATTICE="ladder" MODEL="spin" local_S = 1 J = 1 CONSERVED_QUANTUMNUMBERS="Sz" {L = 4}
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LATTICE="ladder" MODEL="spin" local_S = 1 J0 = 1 J1 = 1 CONSERVED_QUANTUMNUMBERS="Sz" {L = 4}
========================== I run fulldiag then fulldiag_evaluate
fulldiag_evaluate --T_MIN 0.1 --T_MAX 10 --DELTA_T 0.1 parm6a.task1.out.xml as given in the web page http://alps.comp-phys.org/mediawiki/index.php/ALPS_2_Tutorials:ED-06_FullDia...
Would you please help me to understand why the results are different?
Thanks, Ruben