Entanglement in the quantum one-dimensional integer spin S Heisenberg antiferromagnet

摘要

We use the modified spin wave theory of Takahashi to study the entanglement entropy in the quantum one-dimensional integer spin Heisenberg antiferromagnet. We calculate the entanglement entropy of this spin system that is well known to be a quantum wire, in the classical limit (N -> infinity). We obtain a decreasing the entanglement entropy with the temperature and we obtain none change in the entanglement in the point Delta = 1 at T = 0 where the system presents a quantum phase transition from a gapless phase in the spectrum Delta < 1 to a gapped phase Delta >= 1. (C) 2017 Elsevier B.V. All rights reserved.