Strongly chaotic quantum systems are often difficult to study. This fact underlies some of the most challenging problems in quantum field theory, condensed matter physics, and quantum gravity. However, recent work on black holes and a new class of large N models has led to some understanding of the phenomenology of quantum chaos. It has revealed a new set of observables to calculate and measure and a new toolbox of solvable systems with which to study them. However, we believe that the lessons for black hole physics and for holographic duality have not been fully understood. In particular, how does a tranquil black hole interior (sometimes?) emerge from a complicated system, making order from chaos? We expect that further progress at the CHORD18 program will aid conceptual understanding of quantum gravity, as well as providing new examples useful for condensed matter physics and quantum field theory.

This program will have three areas of focus. 1) We will push towards new technical results on solvable models extending the Sachdev-Ye-Kitaev model. 2) We will try to extract lessons for holography. What is the bulk dual to the SYK model and its relatives? More generally, how does the Hilbert space of gravity fit into the Hilbert space of the boundary theory? What can solvable models tell us about the black hole interior and breakdown of the gravity description? 3) We will look for lessons for condensed matter systems and effective field theories, attempting to sharpen the relationship between chaos, transport, hydrodynamics, and Regge physics in quantum field theory.