Min-Chul Cha

Universal conductivity in the boson Hubbard model in a magnetic field.

The universal conductivity at the zero-temperature superconductor-insulator transition of the two-dimensional boson Hubbard model is studied for cases both with and without magnetic field by Monte Carlo simulations of the (2+1)-dimensional classical XY model with disorder represented by random bonds correlated along the imaginary time dimension. The effect of the magnetic field is characterized by the frustration f. From the scaling behavior of the stiffness, we determine the quantum dynamical exponent z, the correlation length exponent \ensuremath{\nu}, and the universal conductivity

Superfluid-insulator transitions of two-species bosons in an optical lattice

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PEAK EFFECT AND THE TRANSITION FROM ELASTIC TO PLASTIC DEPINNING

. For the disorder-free model with f=1/2, we obtain z\ensuremath{\approxeq}1, 1/\ensuremath{\nu}\ensuremath{\approxeq}1.5, and

Orientational order and depinning of the disordered electron solid.

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Topological defects, orientational order, and depinning of the electron solid in a random potential

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Superfluid-insulator transition of the Josephson-junction array model with commensurate frustration

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Two peaks in the momentum distribution of bosons in a weakly frustrated two-leg optical ladder

=0.52\ifmmode\pm\else\textpm\fi{}0.03, where

Universal conductivity of two-dimensional films at the superconductor-insulator transition

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Disorder-induced phase transitions in two-dimensional crystals.

is the quantum conductance. We also study the case with f=1/3, in which we find

Universal Conductivity at the Superconductor-Insulator Transition in Two-Dimensions

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