The Nobel committee wrote the prize motivation: «for the discovery of the interplay of disorder and fluctuations in physical systems from atomic to planetary scales.»
After a short introduction, I will focus on Parisi's work on so-called spin glasses.
These are quite generic models of disordered systems. His ideas have given us a language in which to describe such systems. This language is at the origin of a rigorous mathematical description. In physics, his description goes well beyond the somewhat abstract spin glasses;
if time permits, I will illustrate this with a model of mixtures of two types of particles.
