  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.
