DISORDER-INDUCED TEMPERATURE-FLUCTUATIONS IN NONEQUILIBRIUM SYSTEMS

We study the effects on heat diffusion related to the presence of a quenched disorder of impurities at the boundaries. A simple lattice model summarizes the main characteristics of the surface through which the heat flux input is produced. The disorder induces temperature fluctuations which are proportional to the imposed temperature gradient and depend on the distribution of impurities. The existence of a non-linearity in the boundary conditions leads to the renormalization of the Nusselt number.