Relations between transport and chaos in holographic theories

I will describe recent work illustrating general relations between the transport properties and chaotic properties of quantum field theories with holographic duals. I will firstly show how a simple analysis of near-horizon dynamics yields exact constraints on the spectrum of collective excitations. I will then describe how this can be exploited to identify a universal feature in the spectrum, and its implications for the collective transport properties of strongly interacting field theories with gravity duals.