Hi Ryo IGARASHI,
First of all I would like to thank ALPS team for your collaboration and support.
Thanks for your comments and explanations.
Please find my questions below.
Thanks,
Ruben
________________________________
From: Ryo IGARASHI <rigarash(a)hosi.phys.s.u-tokyo.ac.jp>
To: comp-phys-alps-users <comp-phys-alps-users(a)lists.phys.ethz.ch>
Sent: Tue, December 21, 2010 2:12:40 AM
Subject: Re: [ALPS-users] anisotropic Heisenberg model setup
Hi, Ruben,
On Mon, Dec 20, 2010 at 8:36 PM, Ruben Ghulghazaryan <ghulr(a)yahoo.com> wrote:
> By anisotropic model on a ladder I mean that we have two different
> interaction terms in Hamiltonian as shown in the file attached. Thus we have
> two bond types "0" and "1" in horizontal and vertical directions and we want
> to have different interaction terms in horizontal and vertical directions.
This is usual setting, I believe.
[Ruben]---> Yes.
> As far as I understand, according to "spin" model definition J0 parameter
> should be for bond type="0" and J1 for bonds type="1".
This is correct.
[Ruben]---> OK.
> If we set J=1 only then (even if J1=0) all bonds irrespective of their type
> should get 1 as bond term, don't you?
This is simply wrong. J=1 just means J0=1. As Matthias said, all the J1 term
is 0 (J1=Jz1=Jxy1=0) when only J=1 is set.
[Ruben]--->OK. Does it mean that all bond interaction terms will be the same
both in horizontal and vertical directions?
Or, does it mean we have only horizontal bonds with interaction J0=1 and
vertical bonds terms = 0 and we have two non-interacting chains instead of a
ladder?
> In the case we specify J0=1 and J1=1 again all bonds should get 1 as bond
> term and the model results should be the same
> as for setting J only. In this case both isotropic and anisotropic models
> should give similar results.
J0=1 and J1=1 give the symmetric ladder. And thus, you will get the same results
if you specify a symmetric ladder (i.e. all coupling constant is same
IN THE LATTICE DESCRIPTION) with J=1.
[Ruben]--->
I agree and this is what I expect too.
I did an experiment with the following settings which as far as I understand
both should set the same bond interaction term 1 for all bonds:
(a)
LATTICE="ladder"
MODEL="spin"
local_S = 1
J = 1
CONSERVED_QUANTUMNUMBERS="Sz"
{L = 4}
++++++++++++++++++++++++
(b)
LATTICE="ladder"
MODEL="spin"
local_S = 1
J0 = 1
J1 = 1
CONSERVED_QUANTUMNUMBERS="Sz"
{L = 4}
==========================
I run fulldiag then fulldiag_evaluate
fulldiag parm1.in.xml
fulldiag_evaluate --T_MIN 0.1 --T_MAX 10 --DELTA_T 0.1 parm1.task1.out.xml
The results of these two runs are different. I can not understand why the
results should be different.
Does (a) defines a ladder were both horizontal and vertical bond terms are equal
1?
Does (b) defines a ladder were both horizontal and vertical bond terms are equal
since J0=J1=1?
Please see the file attached for illustration.
If these two parameter files use different settings but define the same lattice
and model, then why the results of fulldiag runs are different?
Please let me now if you need more data.
Thanks!
--
Ryo IGARASHI, Ph.D.
rigarash(a)hosi.phys.s.u-tokyo.ac.jp
OpenPGP fingerprint: BAD9 71E3 28F3 8952 5640 6A53 EC79 A280 6A19 2319