Spin glasses and holography

The connections between disordered quantum systems (specifically the Sachdev-Ye-Kitaev model), ensemble averaging, and two-dimensional dilaton gravity underlie much of the recent progress on holography and quantum gravity. While the SYK model is a spin liquid even at low temperatures, closely related disordered systems exhibit a spin glass phase, characterized by ergodicity breaking and slow dynamics. I will discuss simple spin glass models and some of their properties that are of interest from a gravitational point of view. I will propose a holographic interpretation of some crucial features that relates to the fragmentation instability of AdS2 towards a geometry with multiple throats. Based on work with Tarek Anous, Maine Christos, and Subir Sachdev.