Vortex motion and nonlinear response in coupled noisy phase oscillator lattices under shear stress

Vortex motion in coupled phase oscillator lattices is analogous to the dislocation motion in crystals. A single vortex exhibits a glide motion by force at the boundaries. Thermal fluctuations induce the glide motion even below the critical point corresponding to the Peierls stress. The random drift motion is approximated as a random walk in a tilted potential. If the temperature is high, vortices are spontaneously generated. A nonlinear response where the frequency profile is relatively flat in the central region and changes sharply near the boundaries is observed when the vortex density becomes large and nonuniform.