I am trying to calculate the ground state energy of the transverse Ising-Model ( -J*Sx(i)*Sx(j)-h*Sz(i) ) on a simple 1d-chain-lattice with the DMRG and DIRLOOP applications. The results seems to be calculated with a constrained basis even without the CONSERVED_QUANTUMNUMBERS="Sz" parameter (compared to the FULLDIAG where the parameter has its effect on the results). It looks more like the half of a XY-model. So my question is if there is a special problem with the DMRG and DIRLOOP applications and the Ising-Model.
Btw, wenn changing the x- and z-axis then the LOOP application gets the same results as the FULLDIAG, but DIRLOOP aborts with an 'Did not find raising and lowering operators' error.
best regards,
Armin