String Theory seminar - Jay Armas Seminar

Black holes in certain regimes of parameter space are described by long-wavelength effective theories. The resulting dynamics, after integrating out the short-wavelength degrees of freedom, is usually of hydrodynamic and/or elastic character while the resulting theories are relativistic generalisations of theories of fluid mechanics, soap bubbles, fluid droplets or of elasticity of biophysical membranes. I will review several different contexts in which these effective theories can be useful, either in pure gravity, string theory or in the AdS/CFT correspondence and discuss several different types of (in some cases novel) theories of hydrodynamics that have been developed from gravity. In particular, using these theories, I will highlight recent developments in the classification of horizon geometries, in the perturbative construction of non-trivial black holes solutions in pure gravity and the role of minimal surface theory. Furthermore, I will discuss the role of hydrodynamic theories with boundaries and, if time permits, I will also discuss different methods for evaluating the equilibrium partition function and the equations of motion for hydrodynamic fluctuations of branes in string theory.