[ALPS-users] "fulldiag": Can it handle magnetic field coupled to a non-conserved quantity?

Hi all,

I'm new to ALPS, but before I try to learn how to use it, I wanted to resolve an ambiguity in the documentation to figure out whether it's applicable to my problem. I want to find the magnetic susceptibility for a spin system, where the magnetic field h couples to Sz_tot as usual. However, I wish to use a Hamiltonian that does not commute with Sz_tot, hence does not leave it conserved.

In the fulldiag "documentation" file http://alps.comp-phys.org/mediawiki/index.php/Documentation:FullDiagonalizat... there is a red warning claiming that I cannot use fulldiag if Sz_tot is not conserved. However, this documentation looks like it's two years old.

The new tutorial, at http://alps.comp-phys.org/mediawiki/index.php/ALPS_2_Tutorials:ED-06_FullDia... has no such warning, but it only gives an example for calculating the susceptibility for a Heisenberg Hamiltonian, which conserves Sz_tot.

Do you know if I can use fulldiag (or anything else) if my Sz_tot is not conserved?

Thanks!

Itamar