Critical Point of the One-Dimensional Boson Hubbard Model

Abstract

We study the one-dimensional boson Hubbard model through the exact diagonalization of the Hamiltonian for the periodic boundary condition. Using the finite-size scaling of the energy increase due to a twist imposed on the boundaries, we can successfully determine, even in small systems, the critical value of the tuning parameter (t/U)(c) = 0.283 +/- 0.005 for the commensurate density with one boson per site, a distinct improvement in accuracy compared to previous studies.