Towards a theory of strange quantum metals

Electrons in a conventional metal are described by Landau's celebrated theory of Fermi liquids. In the last few decades a growing number of metals have been discovered that defy a description in terms of Fermi liquid theory. Prominently, such `strange metals'  appear as parent phases out of which phenomena such as high temperature superconductivity develop. However their theoretical understanding has mostly remained mysterious.  In this talk, I will discuss, in great generality, some properties of  `strange  metals' in an ideal clean system.  I will discuss general constraints on the emergent low energy symmetries  of any such strange metal. I will show how these model-independent considerations lead to concrete experimental predictions about a class of strange metals. Time permitting, I will discuss the utility of a focus on the emergent symmetries to reliably extract some physical properties of certain models of strange metals.