Nonlinear supratransmission in fractional wave systems

Abstract

In this work, we review various nonlinear systems with fractional derivatives of the Riesz type in space. Concretely, we consider partial differential equations with fractional Laplacians, which consider potentials of the Fermi–Pasta–Ulam, sine-Gordon, Klein–Gordon and double sine-Gordon. These regimes have the important feature that some energy functional is available in the fractional scenario. For each of these cases, we propose numerical techniques to approximate their solutions, and some discrete functionals are provided in order to approximate the energy dynamics of the systems. The methodologies are energy-preserving (conservative) techniques which are employed then to investigate the presence of nonlinear supratransmission in those systems. It is well known that such process is present in continuous Fermi–Pasta–Ulam, sine-Gordon, Klein–Gordon and double sine-Gordon regimes when the derivatives are of integer order. As one of the most important outcomes of this survey, the computer simulations confirm that this process is also present when the derivatives are of fractional order.