Blowup of the local energy of linear waves at the Reissner-Nordstr\"om-AdS Cauchy horizon

Abstract

We show that generic linear perturbations $\psi$ solving $\Box_g \psi + \frac{\alpha}{l^2} \psi =0$ on Reissner-Nordstr\"om-AdS black holes have infinite local energy at the Cauchy horizon. Combined with the result of arXiv:1812.06142 that such perturbations $\psi$ remain uniformly bounded and extend continuously across the Cauchy horizon, this settles the linear analog of the Strong Cosmic Censorship conjecture for Reissner-Nordstr\"om-AdS: the $C^0$-formulation is false but the $H^1$-formulation is true.