Process-chain approach and its application to bosonic lattice systems

Author(s): Dennis Hinrichs, Niklas Teichmann, Martin Holthaus
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Keywords: Bose-Hubbard model, phase diagram, Mott insulator, superfluid, triangular, hexagonal
Abstract:: We study the transition from a Mott insulator to a superfluid in the Bose-Hubbard model at zero temperature for different lattice types. Converting Kato's perturbation series into an efficient numerical algorithm capable of reaching high orders, we obtain accurate critical parameters for any filling factor g and dimensionality d. Furthermore we clarify the g- and the d-dependence of the critical value and devise a method for extracting the critical value from the correlation function.