Disorder-Induced Order in Quantum XY Chains

TL;DR

This paper demonstrates how disorder can induce order in quantum XY spin chains, revealing a quantum phase transition characterized by increased magnetization orthogonal to a random external field, with implications for ultra-cold atom experiments.

Contribution

It provides numerical evidence of disorder-induced order and analyzes the quantum phase transition in 1D XY chains with random external fields.

Findings

Magnetization orthogonal to the external field increases due to disorder.

Scaling behavior of block-entropy with field amplitude shows criticality.

Potential realization of effects in ultra-cold atom experiments.

Abstract

We observe signatures of disorder-induced order in 1D XY spin chains with an external, site-dependent uni-axial random field within the XY plane. We numerically investigate signatures of a quantum phase transition at T=0, in particular an upsurge of the magnetization in the direction orthogonal to the external magnetic field, and the scaling of the block-entropy with the amplitude of this field. Also, we discuss possible realizations of this effect in ultra-cold atom experiments.