Critical properties and phase diagram of the quantum anisotropic XY spin chain in a random magnetic field: A density-matrix renormalization-group analysis

TL;DR

This study uses density-matrix renormalization group methods to analyze the phase diagram and critical properties of a quantum anisotropic XY spin chain subjected to a random magnetic field, revealing universality with the quantum Ising model.

Contribution

It provides a detailed numerical analysis of the phase diagram and critical behavior of the anisotropic XY chain in a random field, highlighting universality classes.

Findings

Identified the critical line for the order-disorder transition.

Mapped the phase diagram of the model.

Confirmed universality with the quantum Ising model.

Abstract

The spin-1/2 quantum anisotropic XY spin chain in a transverse random magnetic field parallel to the z axis is numerically studied by means of the density-matrix renormalization group. The dependence of the spontaneous magnetization and the energy gap on both the strength of the random magnetic field and the factor of anisotropy is determined. The critical line for the order-disorder phase transition is obtained and the resulting phase diagram is drawn. Our results are compatible with the fact that models with different factors of anisotropy fall within the same universality class as the quantum Ising model in a transverse random field.