Quantum phase transition in easy-axis antiferromagnetic Heisenberg spin-1 chain

TL;DR

This paper investigates quantum phase transitions in an easy-axis antiferromagnetic Heisenberg spin-1 chain using numerical methods, focusing on fidelity and entropy as indicators of phase changes.

Contribution

It demonstrates that fidelity effectively characterizes the phase transition, while entropy shows limited sensitivity, providing new insights into detecting quantum phase transitions.

Findings

Fidelity detects the phase transition accurately.

Entropy shows limited detection capability.

First deviation of entropy indicates phase transition.

Abstract

The fidelity and entropy in an easy-axis antiferromagnetic Heisenberg spin-1 chain are studied numerically. By using the method of density-matrix renormalization group, the effects of anisotropy on fidelity and entanglement entropy are investigated. Their relations with quantum phase transition are analyzed. It is found that the quantum phase transition from the Haldane spin liquid to N\'eel spin solid can be well characterized by the fidelity. The phase transition can be hardly detected by the entropy but it can be successfully detected by the first deviation of the entropy.