Entanglement entropy and topological properties in a long-range non-Hermitian Su-Schrieffer-Heeger model

We employ entanglement entropy to investigate the topological properties of the extended long-range non Hermitian Su-Schrieffer-Heeger (SSH) model. We show how long-range hopping, nearest-neighbor hopping, and the non-Hermitian term influence the entanglement entropy in the SSH model, which serves as a valuable tool for examining the topological features of the SSH model. Our research reveals a remarkable phenomenon: entanglement entropy exhibits singular behavior in specific regions that precisely align with the spatial locations of topological phase transitions in the extended long-range SSH model. These findings are further supported by the application of winding numbers and energy spectra, offering comprehensive evidence for the topological aspects of both Hermitian and non-Hermitian SSH models. As a result, the singularity in entanglement entropy provides a robust framework for characterizing topological phase transitions.