Viscosity, quark gluon plasma, and string theory

Abstract

Viscosity is a very old concept which was introduced to physics by Navier in the 19th century. However, in strongly coupled systems, the viscosity is usually difficult to compute. In this talk I will describe how gauge/gravity duality, a by-product of string theory, allows one to compute the viscosity for a class of strongly interacting fluids not too dissimilar to the quark gluon plasma. I will also describe efforts to measure the viscosity and other physical properties of the quark gluon plasma at the Relativistic Heavy Ion Collider.