Year: 2026
Type: preprint
Abstract: We investigate nonlinear photon motion in the vicinity of a rotating black hole (BH) within Weyl conformal gravity (WCG) by employing Poincare sections, Lyapunov exponents, Fast Lyapunov Indicators (FLI), Kolmogorov-Sinai (KS) entropy, and Discrete Indicator of Chaos (DIG) maps. The joint influence of BH spin and higher order curvature corrections, governed by the parameters $ξ$ and $γ$, induces a transition from nearly integrable trajectories to markedly chaotic dynamics in the strong field domain. As $ξ$ and $γ$ increase, the invariant tori are increasingly deformed and eventually break up. Resonance islands and stochastic layers then form, producing large chaotic regions in phase space, especially near the extremal spin regime. Increasing Lyapunov exponents, faster FLI growth, and higher KS entropy provide quantitative measures of the enhanced dynamical instability, the increased sensitivity to initial conditions, and the corresponding rate of information production. DIG maps show shrinking regular regions and expanding chaotic domains around the photon sphere, indicating that conformal gravity corrections destabilize null circular orbits. Taken together, these findings clarify how relativistic frame dragging and higher order curvature terms jointly control photon chaos and point to nonlinear photon dynamics as a potential probe of departures from General Relativity in the strong-gravity regime.
Source: arXiv (Cornell University)
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7223069798