Bound on Lyapunov exponent in Einstein-Maxwell-Dilaton-Axion black holes

Abstract

In this paper, we investigate the influence of the angular momentum of a charged particle on the bound for the Lyapunov exponent of the chaos in non-extreme and extreme Einstein-Maxwell-Dilaton-Axion black holes. The derivation of the exponent is relied on the effective potential of the particle. We find that when the angular momentum takes the specific values, the bound is violated at the certain distances from the event horizons. This violation always exists when the rotation parameter of the black holes is large enough and the rotation direction of the particle is opposite to that of the black holes. In the near-horizon regions, the violation of the bound is dependent on the rotation directions of the extreme black hole and particle, and independent on the value of the angular momentum of the particle in the non-extreme black hole.

Violation of bound on chaos for charged probe in Kerr-Newman-AdS black hole

“…In this work, we investigate the bound on the Lyapunov exponent for a charged particle with angular motion in a Kerr-Newman-AdS (KN-AdS) black hole. The rotating black hole was considered by [57,58], but they did not use the cosmological constant. Particularly, we consider the negative cosmological constant, so the boundary of the spacetime is AdS.…”