I-Vcharacteristics of high-temperature superconductors with columnar defects

The vortex glass transition in the presence of columnar defects is studied by Monte Carlo simulations of a vortex loop model, suggested by the analogy to the T=0 superconductor-insulator transition for dirty bosons in (2+1) dimensions. From finite-size scaling analysis of the I-V characteristic we find two dynamical exponents describing the nonequilibrium behavior. We obtain ${\mathit{z}}_{\mathrm{\perp }}$=6±0.5 and ${\mathit{z}}_{\mathrm{\parallel }}$=4±0.5 when the current is applied perpendicular and parallel to the columnar defects, respectively.