A Quantum Phase Transition in Hard-Core Bosons on an Optical Lattice in Three Dimensions

In recent years, ultracold atomic gases have provided new experimental realization of the superfluid phase transition, and experiments where atoms are confined to an optical lattice -- a grid of counter-propagating lasers which generate a standing periodic potential -- allow for excellent control of interaction strength and particle density. The Bose-Hubbard Model (BHM) describes interacting bosons confined to an optical lattice. Previous work on the hard-core three-dimensional Bose-Hubbard model with periodic 'checkerboard' potential has demonstrated the existence of a superfluid-insulator phase transition and established bounds on temperature and superlattice potential within which these phase transitions may occur. However, a quantitative phase diagram for this transition was heretofore unestablished. Using a QMC simulation in tandem with finite-size scaling methods, we locate precise values for the critical transition points.