Entanglement, fidelity, and quantum phase transition in antiferromagnetic-ferromagnetic alternating Heisenberg chain

TL;DR

This paper investigates how entanglement entropy and fidelity can characterize quantum phase transitions in an antiferromagnetic-ferromagnetic alternating Heisenberg chain, revealing that these measures effectively identify transition points.

Contribution

It demonstrates that ground-state entropy and fidelity reliably indicate quantum phase transitions in the studied spin chain model.

Findings

Quantum phase transition points are well characterized by entropy and fidelity.

Fidelity and entanglement entropy are sensitive to anisotropy effects.

Large system sizes improve the accuracy of transition detection.

Abstract

The fidelity and entanglement entropy in an antiferromagnetic-ferromagnetic alternating Heisenberg chain are investigated by using the method of density-matrix renormalization-group. The effect of anisotropy on fidelity and entanglement entropy are investigated. The relations between fidelity, entanglement entropy and quantum phase transition are analyzed. It is found that the quantum phase transition point can be well characterized by both the ground-state entropy and fidelity for large system.