Array-enhanced friction in the periodic stick-slip motion of nonlinear oscillators

We study the nonlinear contribution to stick-slip motion in a weakly coupled discrete one-dimensional array of oscillators subject to a periodic potential. We find a dramatic increase in the friction coefficient of the array compared to that of a single uncoupled oscillator, even though the same constant force f is applied to each oscillator in the array. The sliding friction coefficient is found to diverge as eta not congruent to (kappa- kappa(c))(-1/2), where kappa(c) is the critical value of the coupling constant kappa, and shows two dynamical transitions as we increase the external force f applied to each of the oscillators.