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Description
We study the classical chaoticity of the glasma, the far-from-equilibrium gluonic state formed in the early stages of heavy-ion collisions, using 2+1D real-time lattice simulations within the McLerran-Venugopalan model. By monitoring the evolution of small perturbations in boost-invariant color fields, we demonstrate that fluctuations grow exponentially as $\sim \exp(\lambda \sqrt{g^2\mu\tau})$, where $g^2\mu$ is proportional to the saturation scale, $Q_s$, of the system. Hence, we extract a universal leading Lyapunov exponent of $\lambda \approx 0.39 \pm 0.02$. This growth rate is remarkably robust across various initial momentum-space filters, including Gaussian, power-law, and shell kernels. In particular, the unstable mode couples to all momentum scales present in the initial perturbation. Next, the dominant unstable mode couples both longitudinal electric and magnetic field sectors, which are independent in a purely linearized approximation. Our results suggest that chaos is a collective property of non-linear Yang-Mills dynamics, independent of numerical regulators such as lattice volume and spacing. Moreover, we extend this chaotic analysis to the transport of hard probes, studying their trajectories as they propagate through the evolving non-Abelian fields using Wong's equations.