Inhomogeneous six-wave kinetic equation in exponentially weighted $L^\infty$ spaces (2501.10565v1)

Abstract: Six-wave interactions are used for modeling various physical systems, including in optical wave turbulence 16 and in quantum wave turbulence 31. In this paper, we initiate the analysis of the Cauchy problem for the spatially inhomogeneous six-wave kinetic equation. More precisely, we obtain the existence and uniqueness of non-negative mild solutions to this equation in exponentially weighted $L^\infty_{xv}$ spaces. This is accompanied by an analysis of the long-time behavior of such solutions - we prove that the solutions scatter, that is, they converge to solutions of the transport equation in the limit as $t \to \pm \infty$. Compared with the study of four-wave kinetic equations, the main challenge we face is to address the increased complexity of the geometry of the six-wave interactions.