Chaos and pole skipping in CFT$_2$

Abstract

Recent work has suggested an intriguing relation between quantum chaos and energy density correlations, known as pole skipping. We investigate this relationship in two dimensional conformal field theories on a finite size spatial circle by studying the thermal energy density retarded two-point function on a torus. We find that the location $\omega_* = i \lambda$ of pole skipping in the complex frequency plane is determined by the central charge and the stress energy one-point function $\langle T\rangle$ on the torus. In addition, we find a bound on $\lambda$ in $c>1$ compact, unitary CFT$_2$s identical to the chaos bound, $\lambda \leq 2\pi T$. This bound is saturated in large $c$ CFT$_2$s with a sparse light spectrum, as quantified by arXiv:1405.5137, for all temperatures above the dual Hawking-Page transition temperature.