Chaotic dynamics and bound violation in 4D EGB-AdS black holes with massive gravitons

Recent interest in four-dimensional Einstein–Gauss–Bonnet (EGB) gravity has highlighted its novel modifications to gravitational dynamics, especially in strong-field regimes. We study charged black holes in 4D EGB-Maxwell gravity with a negative cosmological constant, focusing on how the graviton mass and Gauss–Bonnet (GB) coupling affect horizon structure, stability, and chaos. We find that increasing the graviton mass enlarges the horizon and lowers surface gravity, whereas a stronger GB coupling contracts the horizon and also reduces surface gravity. Using Lyapunov exponents, we show that angular momentum enhances instability at fixed graviton mass. In contrast, a larger graviton mass suppresses chaos-bound violations, while a stronger GB coupling amplifies them. Our results reveal how graviton mass, GB coupling, and rotation collectively shape chaotic dynamics in the 4D EGB-AdS black hole background.