Chaotic Dynamics in Extremal Black Holes: A Challenge to the Chaos Bound
Abstract
We investigate chaotic dynamics in extremal black holes by analyzing the motion of massless particles in both Reissner-Nordstr\"{o}m and Kerr geometries. Two complementary approaches (i) taking the extremal limit of non-extremal solutions and (ii) working directly in the extremal background, yield consistent results. We find that, contrary to naive extrapolation of the Maldacena-Shenker-Stanford (MSS) chaos bound, the Lyapunov exponent remains positive even at zero temperature. For Reissner-Nordstr\"{o}m black holes, chaos diminishes but persists at extremality, while for Kerr black holes it strengthens with increasing spin. These results demonstrate that extremal black holes exhibit residual chaotic dynamics that violate the MSS bound, establishing them as qualitatively distinct dynamical phases of gravity.
Keywords
Cite
@article{arxiv.2602.04423,
title = {Chaotic Dynamics in Extremal Black Holes: A Challenge to the Chaos Bound},
author = {Surojit Dalui and Chiranjeeb Singha and Krishnakanta Bhattacharya},
journal= {arXiv preprint arXiv:2602.04423},
year = {2026}
}
Comments
24 Pages, 8 Figures, To appear in PLB