https://arxiv.org/abs/cond-mat/0211703 Enjoy Sent from my Samsung Galaxy smartphone. -------- Original message --------From: adfws <ll070616@126.com> Date: 20/09/2018 05:51 (GMT+01:00) To: comp-phys-alps-users@lists.phys.ethz.ch Subject: [ALPS-users] Why spin 1 chain is added two spin 1/2 sites at its   both ends? Hi everyone, I'm reading DMRG tutorials in http://alps.comp-phys.org/mediawiki/index.php/ALPS_2_Tutorials:DMRG-01_DMRG. When treating spin 1 Heisenberg chain with open boundary conditions, 2 spin 1/2 sites were added to both ends of the spin 1 chain. Why? I have completely no idea about this special treatment. Can anyone give further explanations? LiuBiao ll070616@126.com ---- Comp-phys-alps-users Mailing List for the ALPS Project http://alps.comp-phys.org/ List info: https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users Archive: https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users Unsubscribe by writing a mail to comp-phys-alps-users-leave@lists.phys.ethz.ch.