Ground-State Fidelity and Bipartite Entanglement in the Bose-Hubbard Model

TL;DR

This paper uses quantum-information tools like ground-state fidelity and entanglement measures to analyze the quantum phase transition in the Bose-Hubbard model, providing accurate estimates of the critical point.

Contribution

It demonstrates that finite-size scaling of fidelity and entanglement measures effectively identifies quantum critical points in the Bose-Hubbard model.

Findings

Fidelity accurately pinpoints the quantum critical point.

Entanglement measures' effectiveness varies with transition mechanisms.

Finite-size scaling yields precise estimates for critical points.

Abstract

We analyze the quantum phase transition in the Bose-Hubbard model borrowing two tools from quantum-information theory, i.e. the ground-state fidelity and entanglement measures. We consider systems at unitary filling comprising up to 50 sites and show for the first time that a finite-size scaling analysis of these quantities provides excellent estimates for the quantum critical point.We conclude that fidelity is particularly suited for revealing a quantum phase transition and pinning down the critical point thereof, while the success of entanglement measures depends on the mechanisms governing the transition.