Dispersive decay for the energy-critical nonlinear wave equation
Matthew Kowalski
TL;DR
We study pointwise-in-time dispersive decay for the energy-critical nonlinear wave equation in spatial dimension $d=3$ with data in the energy space $\dot{H}^1\times L^2$. Using a bootstrap framework built on frequency-localized dispersive bounds for the linear propagator $e^{\pm i t|\nabla|}$ and careful paraproduct-based nonlinear estimates, we obtain nonlinear analogues of linear dispersion: for $2<p<\infty$ the solution satisfies $\|u(t)\|_{L^p} \lesssim C(...) \;|t|^{-(1-\frac{2}{p})}$ with a data- dependent constant, and a Besov refinement yields $L^\infty$-decay under stronger Besov data. An edge theorem further strengthens decay in Besov spaces via an $\ell^1$ summation over frequencies. The results extend nonlinear dispersion theory for the energy-critical NLW by demonstrating precise, frequency-localized decay without requiring Lorentz-space spacetime bounds, and they provide a robust method for achieving pointwise decay in critical nonlinear wave models.
Abstract
We prove pointwise-in-time dispersive decay for solutions to the energy-critical nonlinear wave equation in spatial dimension $d = 3$.
