文摘
We consider a harmonic chain perturbed by a stochastic noise which conserves the energy and a second quantity called the volume, and destroys all the other ones. We then add to this model a second energy conserving noise depending on a parameter \(\gamma \), that annihilates the volume conservation. When \(\gamma \) is of order one, the energy diffuses according to the standard heat equation after a space-time diffusive scaling. On the other hand, when \(\gamma =0\), the energy superdiffuses according to a \(3/4\)-fractional heat equation after a subdiffusive space-time scaling. In this paper, we study the existence of a crossover between these two regimes as a function of \(\gamma \).