Critical conductance of the chiral 2d randomfluxmodel

The two-terminal conductance of a random flux model defined on a square lattice is investigated numerically at the band center using a transfer matrix method. Due to the chiral symmetry, there exists a critical point where the ensemble averaged mean conductance is scale independent. We also study the conductance distribution function which depends on the boundary conditions and on the number of lattice sites being even or odd. We apply one-parameter finite size scaling and derive a critical exponent ν = 0.42± 0.05 in agreement with our previous results for the divergence of the localization length.