Hydrodynamics, Spontaneously Broken Symmetries, and Holography

Hydrodynamics has a rich history with a wide array of applications, ranging from models of stars to graphene. Motivated by results in condensed matter physics, recent years have seen an increased interest in studying hydrodynamics of theories with broken symmetries; meaning that one needs to consider new gapless (or weakly gapped) degrees of freedom in the system. Theories which exhibit broken translational invariance have been of particular interest. One avenue to study such systems is via the gauge/gravity-duality. For example, a particular class of massive gravity models may be used to effectively capture the infrared dynamics of a boundary theory with (pseudo-spontaneous) translational symmetry breaking. This talk will discuss some important hydrodynamic principles; the implementation of spontaneous translational symmetry breaking (for both the gauge/gravity and hydrodynamic set-ups); as well as present some recent results, which show a currently unresolved discrepancy between hydrodynamic predictions and the holographic result.