Exploring the hydrodynamic limit of many-body quantum systems
Andy Lucas

The emergence of hydrodynamics in complicated microscopic many-body models has been a problem of  interest in physics for more than a century.   In this talk, I will describe two of the diverse lessons that the classical theory of hydrodynamics  can teach us about interacting  quantum systems.   Firstly, I will describe the electrical and  thermal conductivity of a fluid of  electrons in  a metal.   Hydrodynamic effects can lead to parametric violations of  textbook results such as the Wiedemann-Franz law.  I will provide possible hydrodynamic origins for some puzzling transport mysteries in solid-state physics.  Secondly, I will derive the constraints relating hydrodynamic phenomena to the spreading of quantum information and chaos.   By studying exotic quantum systems, including those holographically dual to a black hole, we find a number of  non-trivial theories where bounds relating quantum chaos and classical diffusion  are saturated.   This provides simple experimental constraints on quantum chaos, a theory whose predictions have otherwise proven difficult to measure.