Quantum Correlations in a Few-Atom Spin-1 Bose-Hubbard Model

TL;DR

This paper investigates quantum correlations and entanglement in a small spin-1 Bose-Hubbard model, revealing how energy level crossings affect these quantum properties at finite temperatures.

Contribution

It introduces a new measure for non-classical correlations based on zero-discord states and analyzes their behavior alongside entanglement in a few-atom system.

Findings

Energy level crossings are signaled by changes in quantum correlations.

Thermal quantum correlations and entanglement are sensitive to ground state transitions.

The new measure effectively captures non-classical correlations beyond entanglement.

Abstract

We study the thermal quantum correlations and entanglement in spin-1 Bose-Hubbard model with two and three particles. While we use negativity to calculate entanglement, more general non-classical correlations are quantified using a new measure based on a necessary and sufficient condition for zero-discord state. We demonstrate that the energy level crossings in the ground state of the system are signalled by both the behavior of thermal quantum correlations and entanglement.