The universal dielectric response and its physical significance

The dielectric response of virtually all solid dielectrics follows fractional power laws in frequency and in time and these call for a fresh appraisal of the physical significance of these laws. A brief overview of the experimental situation in a wide range of systems is given, and a number of possible interpretations which depart radically from the traditional picture of independently relaxing entities are discussed. It is suggested that a new consensus is appearing for the understanding of the underlying processes leading to the observed universality.>