Entanglement Entropy in an Antiferromagnetic Heisenberg Spin Chain with Boundary Impurities

TL;DR

This paper investigates how boundary impurities affect entanglement entropy in an antiferromagnetic Heisenberg spin chain, revealing that impurities can enhance entanglement and that entropy approaches a constant for large systems.

Contribution

It introduces the impact of boundary impurities and higher-spin impurities on entanglement entropy in Heisenberg chains using density-matrix renormalization-group methods.

Findings

Entanglement entropy increases with subsystem size.

Entropy approaches a constant in large systems.

Higher-spin impurities can increase entanglement entropy.

Abstract

The effects of boundary impurities on the entanglement entropy in an antiferromagnetic Heisenberg opened spin-$1/2$ chain are investigated. The method of density-matrix renormalization-group is used to obtain the bipartite entanglement. The entropy increases when the length of the subsystem increases. It will approach to a constant when system length is very large. With the same impurity interaction, qutrit impurities of spin-$1$ can increase the entanglement entropy.