Exact SU(2) Yang-Mills Waves from a Simple Ansatz

Abstract

We propose a simple ansatz that reduces the sourceless SU(2) Yang--Mills equations in (3+1) dimensions to nine algebraic constraints. Solving these constraints yields three closed-form families of exact wave solutions. \textbf{Family I} embeds linear electromagnetic waves into the non-Abelian theory, with vanishing commutators and dispersion \(ω= kc\). \textbf{Family II} describes genuinely nonlinear self-interacting waves that also propagate at the speed of light but exhibit a constant, gauge-invariant offset in the color-electric field, nonvanishing commutators, and a discrete topological parameter \(ξη= \pm 1\) that controls the position of energy-density nodes (\(θ=0\) or \(θ=π\)). This provides an observable signature with no analogue in Abelian electromagnetism. \textbf{Family III} is a pure gauge solution with vanishing field strengths, valid for arbitrary \(k\) and \(ω\) without any dispersion relation. These exact solutions offer new insights into how non-Abelian self-interactions fundamentally alter wave propagation and serve as benchmarks for numerical simulations, perturbative studies, and experiments on synthetic non-Abelian gauge fields.