The Third Law of Black Hole Dynamics in Pure Lovelock Gravity

TL;DR

The paper investigates the universality of the third law of black hole dynamics within pure Lovelock gravity for charged static black holes. By perturbing mass and charge and extending Wald’s overcharging framework, it derives inequalities that bound perturbations and shows that, near extremality, these bounds converge to a strict condition $\delta M = \phi(r_+)\delta Q$, preventing any finite classical process from driving the surface gravity $\kappa$ to zero. It further proves that extremal black holes cannot be overcharged, thereby preserving horizon integrity and cosmic censorship in this higher-curvature context. The results reinforce the robustness of black hole thermodynamics across gravitational theories and motivate future exploration of quantum effects, backreaction, and rotating/extremal configurations in pure Lovelock gravity.

Abstract

The third law of black hole dynamics states that it is impossible, through any finite sequence of physical processes, to reduce the surface gravity of a black hole to zero. In this work, we examine the validity of this law for static, spherically symmetric charged black holes in the pure Lovelock theory of gravity. By studying infinitesimal variations in mass and charge, we derive a set of inequalities that constrain these variations. Our analysis shows that as the surface gravity approaches zero ($κ\to 0$), the range of admissible perturbations gradually diminishes, thereby forbidding the attainment of extremality through any finite classical process. The saturation of the inequality is interpreted as the emergence of a dynamical barrier near extremality, which prevents further evolution toward the extremal configuration.