Dear Mattias,
Thank you very much for your letter. Please find my questions and comments below.
Thank you in advance, Ruben
________________________________ From: Matthias Troyer troyer@phys.ethz.ch To: comp-phys-alps-users@lists.phys.ethz.ch Sent: Sat, December 18, 2010 1:06:54 PM Subject: Re: [ALPS-users] anisotropic Heisenberg model setup
On Dec 18, 2010, at 5:02 PM, Ruben Ghulghazaryan wrote:
Hi Mattias,
Should i use Jz=1, Jxy=1 and Jz0=1, Jxy0=1, Jz1=1, Jxy1=1 setting for my experiment?
This would be isotropic and not anisotropic.
---> That's correct. This is why, we should expect that the results of simulations be absolutely the same for fulldiag program. But simulations show different results for
Jz=1, Jxy=1 and Jz0=1, Jxy0=1, Jz1=1, Jxy1=1 settings. That is confusing. I want to make sure that anisotropic program works as expected that is why I want to make this experiment and check whether anisotropic model
with the same settings for different bond types and isotropic model with the same interaction bond term give same results. My tests show that the results are not the same and this may be an indication of a problem with program or miss usage from my side.
Would you please help me to understand the problem?
Can use anisotropic Heisenberg model for QWL simulations with ALPS rc4?
No, the qwl at the moment can only do isotropic Heisenberg models at the moment.
--> Ok. Thanks.
Matthias
Thanks, Ruben
From: Matthias Troyer troyer@phys.ethz.ch To: comp-phys-alps-users@lists.phys.ethz.ch Sent: Sat, December 18, 2010 12:51:18 PM Subject: Re: [ALPS-users] anisotropic Heisenberg model setup
Indeed, J is just a short cut for J0. Thus if you only set J, then J1=0
Matthias
On Dec 18, 2010, at 4:50 PM, Ruben Ghulghazaryan wrote:
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}
++++++++++++++++++++++++
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