SuperfluidInsulator Transition in Commensurate Disordered Bosonic Systems: LargeScale Worm Algorithm Simulations
Abstract
We report results of largescale Monte Carlo simulations of superfluidinsulator transitions in disordered commensurate 2D bosonic systems. In the offdiagonal disorder case, we find that the transition is to a gapless incompressible insulator, and its dynamical critical exponent is z=1.5(2). In the diagonaldisorder case, we prove the conjecture that rare statistical fluctuations are inseparable from critical fluctuations on the largest scales and ultimately result in crossover to the generic universality class (apparently with z=2). However, even at strong disorder, the universal behavior sets in only at very large spacetime distances. This explains why previous studies of smaller clusters mimicked a direct superfluid Mottinsulator transition.
 Publication:

Physical Review Letters
 Pub Date:
 January 2004
 DOI:
 10.1103/PhysRevLett.92.015703
 arXiv:
 arXiv:condmat/0301205
 Bibcode:
 2004PhRvL..92a5703P
 Keywords:

 64.60.Cn;
 03.75.Hh;
 05.30.Jp;
 67.40.w;
 Orderdisorder transformations;
 statistical mechanics of model systems;
 Static properties of condensates;
 thermodynamical statistical and structural properties;
 Boson systems;
 Boson degeneracy and superfluidity of <sup>4</sup>He;
 Condensed Matter
 EPrint:
 6 pages, Latex, 7 figures