title: Fluctuations in a diffusive medium with gain.
abstract: We present a stochastic model for amplifying, diffusive media such as, for instance, random lasers. Starting from a simple random-walk model, we derive a stochastic partial differential equation for the energy field which contains a multiplicative random-advection term yielding intermittency and power-law distributions of the field itself. A dimensional analysis indicates that such features are more likely to be observed for small enough samples and in lower spatial dimensions.
authors.affiliation: Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Lepri