Abstract. The parabolic Anderson model is the Cauchy problem for the heat equation with random potential. It offers a case study for the effects that a random, or irregular, environment can have on a diffusion process. The main focus in the present survey is on phenomena that are due to a highly irregular potential, which we model by a spatially independent, identically distributed random field with heavy tails. Among the effects we discuss are random fluctuations in the growth of the total mass, localisation in the weak and almost sure sense, and ageing.2010 Mathematics Subject Classification. Primary 60K37 Secondary 82C44.Keywords. Anderson Hamiltonian, parabolic problem, intermittency, localization, aging, out of equilibrium, random disorder, random medium, heavy tail, polynomial tail, Pareto distribution, Poisson point process, scaling limit.
The parabolic Anderson problemWe consider the heat equation with random potential on the integer lattice Z d and study the Cauchy problem with localised initial datum,whereis the discrete Laplacian, and the potential (ξ(z) :