Stochastic effects in models for materials with multiple scales

Models for materials which are valid on the length scales of day-to-day experience describe quantities which are derived by averaging over many degrees of freedom of a finer length scale. The deviations from this average due to thermal effects or impurities are often negligible. In some situations, however, they can trigger effects which are observable on the rough length scale. This is exemplified by the mathematical investigation of a prototypical model.