SYNCHRONISATION OF KINKS IN SPATIALLY EXTENDED SYSTEMS

Solitonic solutions such as kinks in 1D Ginzburg-Landau theories have the remarkable property of behaving like particles. We investigate the dynamics of kinks in the presence of external random fluctuations. Kinks emerge (disappear) through the production (annihilation) of a kink-antikink pair, they diffuse like Brownian particles and can be driven by external forces. On adding a uniform periodic driving kinks become signal carriers performing oscillations with the same frequency as the driving frequency and amplitude proportional to the driving amplitude. The average signal density carried by the kinks reaches a maximum at an optimal noise intensity giving evidence of stochastic resonance (SR). However, this SR is achieved at significantly lower noise intensities than that displayed by the order parameter emphasizing the differences between the two interpretations of the SR phenomenon. We also study the synchronisation mechanism of the birth-death events by employing the kink lifetime distributions, which enable us to extend the concept of bona fide resonance to spatially extended systems. This resonance is interpreted as a time-scale matching between the average lifetime of the kinks and a characteristic time proportional to the driving period.