Critical properties of the Bose-Hubbard model

Author(s): Dennis Hinrichs, Axel Pelster, Martin Holthaus
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Keywords: Bose-Hubbard model, critical exponents, Mott insulator, superfluid
Abstract:: We study certain critical properties of the superfluid-to-Mott insulator quantum phase transition of the Bose-Hubbard model at zero temperature. By converting Kato’s perturbation series into an efficient numerical algorithm and by applying the method of effective action, we gain access to the phase boundary as well as the superfluid and the condensate density. These calculations allow us to determine the critical exponents in two ways. One of these is based on variational perturbation theory, while the other requires more numerical effort.