The Sensitivity of Black Holes to Low Energy Excitations

A general principle of statistical mechanics is that low energy excitations of a thermal state change expectation values of observables by a very small amount. However some observables in the vicinity of the horizon of a large black hole in anti-de Sitter space naively seem to violate this bound. This potential violation is related to the question of whether the black hole interior can be described in AdS/CFT. Here we point out that if the possible excitations are limited to those produced by a simple local source on the boundary, and the possible observables are limited to products of field operators in a single causal patch in the bulk, then these violations disappear.