Detection of quantum phase transition in spin-1 chain through multipartite high-order correlations

TL;DR

This paper introduces a Bell inequality tailored for spin-1 chains, detecting quantum phase transitions through violations caused by multipartite high-order correlations, revealing a transition to GHZ-like states.

Contribution

It presents a novel Bell inequality for spin-1 systems that detects phase transitions via multi-body correlations and high-order measurements, linking quantum criticality to Bell violations.

Findings

Sharp Bell violation near phase transition point

Ground state transforms into GHZ-like state at criticality

First characterization of phase transition via Bell inequality in spin-1 chains

Abstract

We design a Bell inequality that is violated by correlations obtained from the ground states of XXZ spin-1 chain with on site anisotropies at the region of phase transition. In order to detect such correlations in spin-1 systems we exploit the formalism of generalized Bell inequality via the use of multipartite and high order correlations. We observe sharp violation in the vicinity of quantum phase transition between the so called large D and AFM phase. Interestingly, the violation of our Bell inequality is manifested by the change of the XXZ spin-1 chain ground state to a Greenberger-Horne-Zeilinger (GHZ)-like state at the critical region. Our results provide the first characterization of quantum phase transition via the violation of Bell-type constraint by correlations in the XXZ spin-1 chain with multi-body correlations and high-order measurements.