Dear all,
I would like to use the ALPS dmrg routines to simulate the transversal spin-1/2 XXZ Heisenberg model, i.e., with magnetic field in X-direction.
While a magnetic field in Z-direction [Hz = B*Sz(i)] poses no problems, a magnetic field in X-direction [Hx = B*(Splus(i) + Sminus(i))] destroys convergence completely.
I am aware that Hx violates Sz-conservation, but XXZ+Hz is easily solved by the dmrg package even without assuming conserved quantum numbers, so I guess conserved quantum numbers are probably not an issue for the small systems I'm considering (32 sites). Is the bad convergence in the Hx case something which is expected or do you rather suspect an error in my configuration?
Thanks a lot! Sincerely,
Thomas