ROUGHENING TRANSITION IN A THERMAL SINE-GORDON SYSTEM

We relate the appearance of noise induced solitons in a sine-Gordon sy stem with the roughening exponent, defined as the scaling exponent of the length of the ensemble average of the standard deviation of the he ight of the spatiotemporal profile. We find that before the onset of t he noise-induced transition to the solitonic regime, the roughening ex ponent is zero as would correspond for a white noise signal. After the activation of solitons this exponent exhibits a crossover from approx imately 0.70 to approximately 0.50. We point out the connection of our results to models for surface growth and random deposition, particula rly, the stochastic Kardar-Parisi-Zhang model.