Superfluid-insulator transition in the disordered two-dimensional Bose-Hubbard model

Fei Lin, Erik S. Sørensen, D. M. Ceperley

Research output: Contribution to journalArticlepeer-review

Abstract

We investigate the superfluid-insulator transition in the disordered two-dimensional Bose-Hubbard model through quantum Monte Carlo simulations. The Bose-Hubbard model is studied in the presence of site disorder, and the quantum critical point between the Bose glass and superfluid is determined in the grand canonical ensemble at μ/U=0 (close to ρ=0.5), μ/U=0.375 (close to ρ=1), and μ/U=1 as well as in the canonical ensemble at ρ=0.5 and 1. Particular attention is paid to disorder averaging, and it is shown that a large number of disorder realizations are needed in order to obtain reliable results. Typically, more than 100000 disorder realizations were used. In the grand canonical ensemble, we find Ztc/U=0.112(1) with μ/U=0.375, significantly different from previous studies. When compared to the critical point in the absence of disorder (Ztc/U=0.2385), this result confirms previous findings showing that disorder enlarges the superfluid region. At the critical point, we then study the dynamic conductivity.

Original languageEnglish (US)
Article number094507
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume84
Issue number9
DOIs
StatePublished - Sep 13 2011

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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