Hello professor Troyer,<br><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; I am trying to use ALPS to study a magnetic heisenberg ladder with anti-fm interactions in the rail direction and ferromagnetic interactions in the rung direction. I believed it would be easy to simulate if I set J_rung= 1 and J_rail= -1 but I get the same MvT results whether I do it this way or make it a uniform ladder. Is changing the sign the correct way to simulate ferromagnetic interactions?<br>
<br>thanks for your help, Brian<br>