Hi, Ruben,
On Mon, Dec 20, 2010 at 8:36 PM, Ruben Ghulghazaryan ghulr@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.
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.
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.
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.